ATT&CK explorer

Adversaries disable a network device’s dedicated hardware encryption, which may enable them to leverage weaknesses in software encryption in order to reduce the effort involved in collecting, manipulating, and exfiltrating transmitted data. Many network devices such as routers, switches, and firewalls, perform encryption on network traffic to secure transmission across networks. Often, these devices are equipped with special, dedicated encryption hardware to greatly increase the speed of the encryption process as well as to prevent malicious tampering. When an adversary takes control of such a device, they may disable the dedicated hardware, for example, through use of Modify System Image, forcing the use of software to perform encryption on general processors. This is typically used in conjunction with attacks to weaken the strength of the cipher in software (e.g., Reduce Key Space). (Citation: Cisco Blog Legacy Device Attacks)

Adversaries may make changes to the operating system of embedded network devices to weaken defenses and provide new capabilities for themselves. On such devices, the operating systems are typically monolithic and most of the device functionality and capabilities are contained within a single file. To change the operating system, the adversary typically only needs to affect this one file, replacing or modifying it. This can either be done live in memory during system runtime for immediate effect, or in storage to implement the change on the next boot of the network device.

Adversaries may modify the operating system of a network device to introduce new capabilities or weaken existing defenses.(Citation: Killing the myth of Cisco IOS rootkits) (Citation: Killing IOS diversity myth) (Citation: Cisco IOS Shellcode) (Citation: Cisco IOS Forensics Developments) (Citation: Juniper Netscreen of the Dead) Some network devices are built with a monolithic architecture, where the entire operating system and most of the functionality of the device is contained within a single file. Adversaries may change this file in storage, to be loaded in a future boot, or in memory during runtime. To change the operating system in storage, the adversary will typically use the standard procedures available to device operators. This may involve downloading a new file via typical protocols used on network devices, such as TFTP, FTP, SCP, or a console connection. The original file may be overwritten, or a new file may be written alongside of it and the device reconfigured to boot to the compromised image. To change the operating system in memory, the adversary typically can use one of two methods. In the first, the adversary would make use of native debug commands in the original, unaltered running operating system that allow them to directly modify the relevant memory addresses containing the running operating system. This method typically requires administrative level access to the device. In the second method for changing the operating system in memory, the adversary would make use of the boot loader. The boot loader is the first piece of software that loads when the device starts that, in turn, will launch the operating system. Adversaries may use malicious code previously implanted in the boot loader, such as through the ROMMONkit method, to directly manipulate running operating system code in memory. This malicious code in the bootloader provides the capability of direct memory manipulation to the adversary, allowing them to patch the live operating system during runtime. By modifying the instructions stored in the system image file, adversaries may either weaken existing defenses or provision new capabilities that the device did not have before. Examples of existing defenses that can be impeded include encryption, via Weaken Encryption, authentication, via Network Device Authentication, and perimeter defenses, via Network Boundary Bridging. Adding new capabilities for the adversary’s purpose include Keylogging, Multi-hop Proxy, and Port Knocking. Adversaries may also compromise existing commands in the operating system to produce false output to mislead defenders. When this method is used in conjunction with Downgrade System Image, one example of a compromised system command may include changing the output of the command that shows the version of the currently running operating system. By patching the operating system, the adversary can change this command to instead display the original, higher revision number that they replaced through the system downgrade. When the operating system is patched in storage, this can be achieved in either the resident storage (typically a form of flash memory, which is non-volatile) or via TFTP Boot. When the technique is performed on the running operating system in memory and not on the stored copy, this technique will not survive across reboots. However, live memory modification of the operating system can be combined with ROMMONkit to achieve persistence.

Adversaries may install an older version of the operating system of a network device to weaken security. Older operating system versions on network devices often have weaker encryption ciphers and, in general, fewer/less updated defensive features. (Citation: Cisco Synful Knock Evolution) On embedded devices, downgrading the version typically only requires replacing the operating system file in storage. With most embedded devices, this can be achieved by downloading a copy of the desired version of the operating system file and reconfiguring the device to boot from that file on next system restart. The adversary could then restart the device to implement the change immediately or they could wait until the next time the system restarts. Downgrading the system image to an older versions may allow an adversary to evade defenses by enabling behaviors such as Weaken Encryption. Downgrading of a system image can be done on its own, or it can be used in conjunction with Patch System Image.

Adversaries may collect data related to managed devices from configuration repositories. Configuration repositories are used by management systems in order to configure, manage, and control data on remote systems. Configuration repositories may also facilitate remote access and administration of devices. Adversaries may target these repositories in order to collect large quantities of sensitive system administration data. Data from configuration repositories may be exposed by various protocols and software and can store a wide variety of data, much of which may align with adversary Discovery objectives.(Citation: US-CERT-TA18-106A)(Citation: US-CERT TA17-156A SNMP Abuse 2017)

Adversaries may target the Management Information Base (MIB) to collect and/or mine valuable information in a network managed using Simple Network Management Protocol (SNMP). The MIB is a configuration repository that stores variable information accessible via SNMP in the form of object identifiers (OID). Each OID identifies a variable that can be read or set and permits active management tasks, such as configuration changes, through remote modification of these variables. SNMP can give administrators great insight in their systems, such as, system information, description of hardware, physical location, and software packages(Citation: SANS Information Security Reading Room Securing SNMP Securing SNMP). The MIB may also contain device operational information, including running configuration, routing table, and interface details. Adversaries may use SNMP queries to collect MIB content directly from SNMP-managed devices in order to collect network information that allows the adversary to build network maps and facilitate future targeted exploitation.(Citation: US-CERT-TA18-106A)(Citation: Cisco Blog Legacy Device Attacks)

Adversaries may access network configuration files to collect sensitive data about the device and the network. The network configuration is a file containing parameters that determine the operation of the device. The device typically stores an in-memory copy of the configuration while operating, and a separate configuration on non-volatile storage to load after device reset. Adversaries can inspect the configuration files to reveal information about the target network and its layout, the network device and its software, or identifying legitimate accounts and credentials for later use. Adversaries can use common management tools and protocols, such as Simple Network Management Protocol (SNMP) and Smart Install (SMI), to access network configuration files.(Citation: US-CERT TA18-106A Network Infrastructure Devices 2018)(Citation: Cisco Blog Legacy Device Attacks) These tools may be used to query specific data from a configuration repository or configure the device to export the configuration for later analysis.

Adversaries may forge credential materials that can be used to gain access to web applications or Internet services. Web applications and services (hosted in cloud SaaS environments or on-premise servers) often use session cookies, tokens, or other materials to authenticate and authorize user access. Adversaries may generate these credential materials in order to gain access to web resources. This differs from Steal Web Session Cookie, Steal Application Access Token, and other similar behaviors in that the credentials are new and forged by the adversary, rather than stolen or intercepted from legitimate users. The generation of web credentials often requires secret values, such as passwords, Private Keys, or other cryptographic seed values.(Citation: GitHub AWS-ADFS-Credential-Generator) Adversaries may also forge tokens by taking advantage of features such as the `AssumeRole` and `GetFederationToken` APIs in AWS, which allow users to request temporary security credentials (i.e., Temporary Elevated Cloud Access), or the `zmprov gdpak` command in Zimbra, which generates a pre-authentication key that can be used to generate tokens for any user in the domain.(Citation: AWS Temporary Security Credentials)(Citation: Zimbra Preauth) Once forged, adversaries may use these web credentials to access resources (ex: Use Alternate Authentication Material), which may bypass multi-factor and other authentication protection mechanisms.(Citation: Pass The Cookie)(Citation: Unit 42 Mac Crypto Cookies January 2019)(Citation: Microsoft SolarWinds Customer Guidance)

Adversaries may forge web cookies that can be used to gain access to web applications or Internet services. Web applications and services (hosted in cloud SaaS environments or on-premise servers) often use session cookies to authenticate and authorize user access. Adversaries may generate these cookies in order to gain access to web resources. This differs from Steal Web Session Cookie and other similar behaviors in that the cookies are new and forged by the adversary, rather than stolen or intercepted from legitimate users. Most common web applications have standardized and documented cookie values that can be generated using provided tools or interfaces.(Citation: Pass The Cookie) The generation of web cookies often requires secret values, such as passwords, Private Keys, or other cryptographic seed values. Once forged, adversaries may use these web cookies to access resources (Web Session Cookie), which may bypass multi-factor and other authentication protection mechanisms.(Citation: Volexity SolarWinds)(Citation: Pass The Cookie)(Citation: Unit 42 Mac Crypto Cookies January 2019)

An adversary may forge SAML tokens with any permissions claims and lifetimes if they possess a valid SAML token-signing certificate.(Citation: Microsoft SolarWinds Steps) The default lifetime of a SAML token is one hour, but the validity period can be specified in the <code>NotOnOrAfter</code> value of the <code>conditions ...</code> element in a token. This value can be changed using the <code>AccessTokenLifetime</code> in a <code>LifetimeTokenPolicy</code>.(Citation: Microsoft SAML Token Lifetimes) Forged SAML tokens enable adversaries to authenticate across services that use SAML 2.0 as an SSO (single sign-on) mechanism.(Citation: Cyberark Golden SAML) An adversary may utilize Private Keys to compromise an organization's token-signing certificate to create forged SAML tokens. If the adversary has sufficient permissions to establish a new federation trust with their own Active Directory Federation Services (AD FS) server, they may instead generate their own trusted token-signing certificate.(Citation: Microsoft SolarWinds Customer Guidance) This differs from Steal Application Access Token and other similar behaviors in that the tokens are new and forged by the adversary, rather than stolen or intercepted from legitimate users. An adversary may gain administrative Entra ID privileges if a SAML token is forged which claims to represent a highly privileged account. This may lead to Use Alternate Authentication Material, which may bypass multi-factor and other authentication protection mechanisms.(Citation: Microsoft SolarWinds Customer Guidance)

Adversaries may upload, install, or otherwise set up capabilities that can be used during targeting. To support their operations, an adversary may need to take capabilities they developed (Develop Capabilities) or obtained (Obtain Capabilities) and stage them on infrastructure under their control. These capabilities may be staged on infrastructure that was previously purchased/rented by the adversary (Acquire Infrastructure) or was otherwise compromised by them (Compromise Infrastructure). Capabilities may also be staged on web services, such as GitHub or Pastebin, or on Platform-as-a-Service (PaaS) offerings that enable users to easily provision applications.(Citation: Volexity Ocean Lotus November 2020)(Citation: Dragos Heroku Watering Hole)(Citation: Malwarebytes Heroku Skimmers)(Citation: Netskope GCP Redirection)(Citation: Netskope Cloud Phishing) Staging of capabilities can aid the adversary in a number of initial access and post-compromise behaviors, including (but not limited to): * Staging web resources necessary to conduct Drive-by Compromise when a user browses to a site.(Citation: FireEye CFR Watering Hole 2012)(Citation: Gallagher 2015)(Citation: ATT ScanBox) * Staging web resources for a link target to be used with spearphishing.(Citation: Malwarebytes Silent Librarian October 2020)(Citation: Proofpoint TA407 September 2019) * Uploading malware or tools to a location accessible to a victim network to enable Ingress Tool Transfer.(Citation: Volexity Ocean Lotus November 2020) * Installing a previously acquired SSL/TLS certificate to use to encrypt command and control traffic (ex: Asymmetric Cryptography with Web Protocols).(Citation: DigiCert Install SSL Cert)

Adversaries may upload malware to third-party or adversary controlled infrastructure to make it accessible during targeting. Malicious software can include payloads, droppers, post-compromise tools, backdoors, and a variety of other malicious content. Adversaries may upload malware to support their operations, such as making a payload available to a victim network to enable Ingress Tool Transfer by placing it on an Internet accessible web server. Malware may be placed on infrastructure that was previously purchased/rented by the adversary (Acquire Infrastructure) or was otherwise compromised by them (Compromise Infrastructure). Malware can also be staged on web services, such as GitHub or Pastebin; hosted on the InterPlanetary File System (IPFS), where decentralized content storage makes the removal of malicious files difficult; or saved on the blockchain as smart contracts, which are resilient against takedowns that would affect traditional infrastructure.(Citation: Volexity Ocean Lotus November 2020)(Citation: Talos IPFS 2022)(Citation: Guardio Etherhiding 2023)(Citation: Bleeping Computer Binance Smart Chain 2023) Adversaries may upload backdoored files, such as software packages, application binaries, virtual machine images, or container images, to third-party software stores, package libraries, extension marketplaces, or repositories (ex: GitHub, CNET, AWS Community AMIs, Docker Hub, PyPi, NPM).(Citation: Datadog Security Labs Malicious PyPi Packages 2024) By chance encounter, victims may directly download/install these backdoored files via User Execution. Masquerading, including typo-squatting legitimate software, may increase the chance of users mistakenly executing these files.

Adversaries may upload tools to third-party or adversary controlled infrastructure to make it accessible during targeting. Tools can be open or closed source, free or commercial. Tools can be used for malicious purposes by an adversary, but (unlike malware) were not intended to be used for those purposes (ex: PsExec). Adversaries may upload tools to support their operations, such as making a tool available to a victim network to enable Ingress Tool Transfer by placing it on an Internet accessible web server. Tools may be placed on infrastructure that was previously purchased/rented by the adversary (Acquire Infrastructure) or was otherwise compromised by them (Compromise Infrastructure).(Citation: Dell TG-3390) Tools can also be staged on web services, such as an adversary controlled GitHub repo, or on Platform-as-a-Service offerings that enable users to easily provision applications.(Citation: Dragos Heroku Watering Hole)(Citation: Malwarebytes Heroku Skimmers)(Citation: Intezer App Service Phishing) Adversaries can avoid the need to upload a tool by having compromised victim machines download the tool directly from a third-party hosting location (ex: a non-adversary controlled GitHub repo), including the original hosting site of the tool.

Adversaries may install SSL/TLS certificates that can be used during targeting. SSL/TLS certificates are files that can be installed on servers to enable secure communications between systems. Digital certificates include information about the key, information about its owner's identity, and the digital signature of an entity that has verified the certificate's contents are correct. If the signature is valid, and the person examining the certificate trusts the signer, then they know they can use that key to communicate securely with its owner. Certificates can be uploaded to a server, then the server can be configured to use the certificate to enable encrypted communication with it.(Citation: DigiCert Install SSL Cert) Adversaries may install SSL/TLS certificates that can be used to further their operations, such as encrypting C2 traffic (ex: Asymmetric Cryptography with Web Protocols) or lending credibility to a credential harvesting site. Installation of digital certificates may take place for a number of server types, including web servers and email servers. Adversaries can obtain digital certificates (see Digital Certificates) or create self-signed certificates (see Digital Certificates). Digital certificates can then be installed on adversary controlled infrastructure that may have been acquired (Acquire Infrastructure) or previously compromised (Compromise Infrastructure).

Adversaries may prepare an operational environment to infect systems that visit a website over the normal course of browsing. Endpoint systems may be compromised through browsing to adversary controlled sites, as in Drive-by Compromise. In such cases, the user's web browser is typically targeted for exploitation (often not requiring any extra user interaction once landing on the site), but adversaries may also set up websites for non-exploitation behavior such as Application Access Token. Prior to Drive-by Compromise, adversaries must stage resources needed to deliver that exploit to users who browse to an adversary controlled site. Drive-by content can be staged on adversary controlled infrastructure that has been acquired (Acquire Infrastructure) or previously compromised (Compromise Infrastructure). Adversaries may upload or inject malicious web content, such as JavaScript, into websites.(Citation: FireEye CFR Watering Hole 2012)(Citation: Gallagher 2015) This may be done in a number of ways, including: * Inserting malicious scripts into web pages or other user controllable web content such as forum posts * Modifying script files served to websites from publicly writeable cloud storage buckets * Crafting malicious web advertisements and purchasing ad space on a website through legitimate ad providers (i.e., Malvertising) In addition to staging content to exploit a user's web browser, adversaries may also stage scripting content to profile the user's browser (as in Gather Victim Host Information) to ensure it is vulnerable prior to attempting exploitation.(Citation: ATT ScanBox) Websites compromised by an adversary and used to stage a drive-by may be ones visited by a specific community, such as government, a particular industry, or region, where the goal is to compromise a specific user or set of users based on a shared interest. This kind of targeted campaign is referred to a strategic web compromise or watering hole attack. Adversaries may purchase domains similar to legitimate domains (ex: homoglyphs, typosquatting, different top-level domain, etc.) during acquisition of infrastructure (Domains) to help facilitate Drive-by Compromise.

Adversaries may put in place resources that are referenced by a link that can be used during targeting. An adversary may rely upon a user clicking a malicious link in order to divulge information (including credentials) or to gain execution, as in Malicious Link. Links can be used for spearphishing, such as sending an email accompanied by social engineering text to coax the user to actively click or copy and paste a URL into a browser. Prior to a phish for information (as in Spearphishing Link) or a phish to gain initial access to a system (as in Spearphishing Link), an adversary must set up the resources for a link target for the spearphishing link. Typically, the resources for a link target will be an HTML page that may include some client-side script such as JavaScript to decide what content to serve to the user. Adversaries may clone legitimate sites to serve as the link target, this can include cloning of login pages of legitimate web services or organization login pages in an effort to harvest credentials during Spearphishing Link.(Citation: Malwarebytes Silent Librarian October 2020)(Citation: Proofpoint TA407 September 2019) Adversaries may also Upload Malware and have the link target point to malware for download/execution by the user. Adversaries may purchase domains similar to legitimate domains (ex: homoglyphs, typosquatting, different top-level domain, etc.) during acquisition of infrastructure (Domains) to help facilitate Malicious Link. Links can be written by adversaries to mask the true destination in order to deceive victims by abusing the URL schema and increasing the effectiveness of phishing.(Citation: Kaspersky-masking)(Citation: mandiant-masking) Adversaries may also use free or paid accounts on link shortening services and Platform-as-a-Service providers to host link targets while taking advantage of the widely trusted domains of those providers to avoid being blocked while redirecting victims to malicious pages.(Citation: Netskope GCP Redirection)(Citation: Netskope Cloud Phishing)(Citation: Intezer App Service Phishing)(Citation: Cofense-redirect) In addition, adversaries may serve a variety of malicious links through uniquely generated URIs/URLs (including one-time, single use links).(Citation: iOS URL Scheme)(Citation: URI)(Citation: URI Use)(Citation: URI Unique) Finally, adversaries may take advantage of the decentralized nature of the InterPlanetary File System (IPFS) to host link targets that are difficult to remove.(Citation: Talos IPFS 2022)

Adversaries may poison mechanisms that influence search engine optimization (SEO) to further lure staged capabilities towards potential victims. Search engines typically display results to users based on purchased ads as well as the site’s ranking/score/reputation calculated by their web crawlers and algorithms.(Citation: Atlas SEO)(Citation: MalwareBytes SEO) To help facilitate Drive-by Compromise, adversaries may stage content that explicitly manipulates SEO rankings in order to promote sites hosting their malicious payloads (such as Drive-by Target) within search engines. Poisoning SEO rankings may involve various tricks, such as stuffing keywords (including in the form of hidden text) into compromised sites. These keywords could be related to the interests/browsing habits of the intended victim(s) as well as more broad, seasonably popular topics (e.g. elections, trending news).(Citation: ZScaler SEO)(Citation: Atlas SEO) In addition to internet search engines (such as Google), adversaries may also aim to manipulate specific in-site searches for developer platforms (such as GitHub) to deceive users towards Supply Chain Compromise lures. In-site searches will rank search results according to their own algorithms and metrics such as popularity(Citation: Chexmarx-seo) which may be targeted and gamed by malicious actors.(Citation: Checkmarx-oss-seo) Adversaries may also purchase or plant incoming links to staged capabilities in order to boost the site’s calculated relevance and reputation.(Citation: MalwareBytes SEO)(Citation: DFIR Report Gootloader) SEO poisoning may also be combined with evasive redirects and other cloaking mechanisms (such as measuring mouse movements or serving content based on browser user agents, user language/localization settings, or HTTP headers) in order to feed SEO inputs while avoiding scrutiny from defenders.(Citation: ZScaler SEO)(Citation: Sophos Gootloader)

Adversaries may abuse a container administration service to execute commands within a container. A container administration service such as the Docker daemon, the Kubernetes API server, or the kubelet may allow remote management of containers within an environment.(Citation: Docker Daemon CLI)(Citation: Kubernetes API)(Citation: Kubernetes Kubelet) In Docker, adversaries may specify an entrypoint during container deployment that executes a script or command, or they may use a command such as <code>docker exec</code> to execute a command within a running container.(Citation: Docker Entrypoint)(Citation: Docker Exec) In Kubernetes, if an adversary has sufficient permissions, they may gain remote execution in a container in the cluster via interaction with the Kubernetes API server, the kubelet, or by running a command such as <code>kubectl exec</code>.(Citation: Kubectl Exec Get Shell)

Adversaries may deploy a container into an environment to facilitate execution or evade defenses. In some cases, adversaries may deploy a new container to execute processes associated with a particular image or deployment, such as processes that execute or download malware. In others, an adversary may deploy a new container configured without network rules, user limitations, etc. to bypass existing defenses within the environment. In Kubernetes environments, an adversary may attempt to deploy a privileged or vulnerable container into a specific node in order to Escape to Host and access other containers running on the node. (Citation: AppSecco Kubernetes Namespace Breakout 2020) Containers can be deployed by various means, such as via Docker's <code>create</code> and <code>start</code> APIs or via a web application such as the Kubernetes dashboard or Kubeflow. (Citation: Docker Containers API)(Citation: Kubernetes Dashboard)(Citation: Kubeflow Pipelines) In Kubernetes environments, containers may be deployed through workloads such as ReplicaSets or DaemonSets, which can allow containers to be deployed across multiple nodes.(Citation: Kubernetes Workload Management) Adversaries may deploy containers based on retrieved or built malicious images or from benign images that download and execute malicious payloads at runtime.(Citation: Aqua Build Images on Hosts)

Adversaries may break out of a container or virtualized environment to gain access to the underlying host. This can allow an adversary access to other containerized or virtualized resources from the host level or to the host itself. In principle, containerized / virtualized resources should provide a clear separation of application functionality and be isolated from the host environment.(Citation: Docker Overview) There are multiple ways an adversary may escape from a container to a host environment. Examples include creating a container configured to mount the host’s filesystem using the bind parameter, which allows the adversary to drop payloads and execute control utilities such as cron on the host; utilizing a privileged container to run commands or load a malicious kernel module on the underlying host; or abusing system calls such as `unshare` and `keyctl` to escalate privileges and steal secrets.(Citation: Docker Bind Mounts)(Citation: Trend Micro Privileged Container)(Citation: Intezer Doki July 20)(Citation: Container Escape)(Citation: Crowdstrike Kubernetes Container Escape)(Citation: Keyctl-unmask) Additionally, an adversary may be able to exploit a compromised container with a mounted container management socket, such as `docker.sock`, to break out of the container via a Container Administration Command.(Citation: Container Escape) Adversaries may also escape via Exploitation for Privilege Escalation, such as exploiting vulnerabilities in global symbolic links in order to access the root directory of a host machine.(Citation: Windows Server Containers Are Open) In ESXi environments, an adversary may exploit a vulnerability in order to escape from a virtual machine into the hypervisor.(Citation: Broadcom VMSA-2025-004) Gaining access to the host may provide the adversary with the opportunity to achieve follow-on objectives, such as establishing persistence, moving laterally within the environment, accessing other containers or virtual machines running on the host, or setting up a command and control channel on the host.

Adversaries may build a container image directly on a host to bypass defenses that monitor for the retrieval of malicious images from a public registry. A remote <code>build</code> request may be sent to the Docker API that includes a Dockerfile that pulls a vanilla base image, such as alpine, from a public or local registry and then builds a custom image upon it.(Citation: Docker Build Image) An adversary may take advantage of that <code>build</code> API to build a custom image on the host that includes malware downloaded from their C2 server, and then they may utilize Deploy Container using that custom image.(Citation: Aqua Build Images on Hosts)(Citation: Aqua Security Cloud Native Threat Report June 2021) If the base image is pulled from a public registry, defenses will likely not detect the image as malicious since it’s a vanilla image. If the base image already resides in a local registry, the pull may be considered even less suspicious since the image is already in the environment.

Adversaries may attempt to discover containers and other resources that are available within a containers environment. Other resources may include images, deployments, pods, nodes, and other information such as the status of a cluster. These resources can be viewed within web applications such as the Kubernetes dashboard or can be queried via the Docker and Kubernetes APIs.(Citation: Docker API)(Citation: Kubernetes API) In Docker, logs may leak information about the environment, such as the environment’s configuration, which services are available, and what cloud provider the victim may be utilizing. The discovery of these resources may inform an adversary’s next steps in the environment, such as how to perform lateral movement and which methods to utilize for execution.

Adversaries may gather information in an attempt to calculate the geographical location of a victim host. Adversaries may use the information from System Location Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions. Adversaries may attempt to infer the location of a system using various system checks, such as time zone, keyboard layout, and/or language settings.(Citation: FBI Ragnar Locker 2020)(Citation: Sophos Geolocation 2016)(Citation: Bleepingcomputer RAT malware 2020) Windows API functions such as <code>GetLocaleInfoW</code> can also be used to determine the locale of the host.(Citation: FBI Ragnar Locker 2020) In cloud environments, an instance's availability zone may also be discovered by accessing the instance metadata service from the instance.(Citation: AWS Instance Identity Documents)(Citation: Microsoft Azure Instance Metadata 2021) Adversaries may also attempt to infer the location of a victim host using IP addressing, such as via online geolocation IP-lookup services.(Citation: Securelist Trasparent Tribe 2020)(Citation: Sophos Geolocation 2016)

Adversaries may attempt to gather information about the system language of a victim in order to infer the geographical location of that host. This information may be used to shape follow-on behaviors, including whether the adversary infects the target and/or attempts specific actions. This decision may be employed by malware developers and operators to reduce their risk of attracting the attention of specific law enforcement agencies or prosecution/scrutiny from other entities.(Citation: Malware System Language Check) There are various sources of data an adversary could use to infer system language, such as system defaults and keyboard layouts. Specific checks will vary based on the target and/or adversary, but may involve behaviors such as Query Registry and calls to Native API functions.(Citation: CrowdStrike Ryuk January 2019) For example, on a Windows system adversaries may attempt to infer the language of a system by querying the registry key <code>HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\Language</code> or parsing the outputs of Windows API functions <code>GetUserDefaultUILanguage</code>, <code>GetSystemDefaultUILanguage</code>, <code>GetKeyboardLayoutList</code> and <code>GetUserDefaultLangID</code>.(Citation: Darkside Ransomware Cybereason)(Citation: Securelist JSWorm)(Citation: SecureList SynAck Doppelgänging May 2018) On a macOS or Linux system, adversaries may query <code>locale</code> to retrieve the value of the <code>$LANG</code> environment variable.

Adversaries may gather information on Group Policy settings to identify paths for privilege escalation, security measures applied within a domain, and to discover patterns in domain objects that can be manipulated or used to blend in the environment. Group Policy allows for centralized management of user and computer settings in Active Directory (AD). Group policy objects (GPOs) are containers for group policy settings made up of files stored within a predictable network path `\<DOMAIN>\SYSVOL\<DOMAIN>\Policies\`.(Citation: TechNet Group Policy Basics)(Citation: ADSecurity GPO Persistence 2016) Adversaries may use commands such as <code>gpresult</code> or various publicly available PowerShell functions, such as <code>Get-DomainGPO</code> and <code>Get-DomainGPOLocalGroup</code>, to gather information on Group Policy settings.(Citation: Microsoft gpresult)(Citation: Github PowerShell Empire) Adversaries may use this information to shape follow-on behaviors, including determining potential attack paths within the target network as well as opportunities to manipulate Group Policy settings (i.e. Domain or Tenant Policy Modification) for their benefit.

Adversaries may enumerate objects in cloud storage infrastructure. Adversaries may use this information during automated discovery to shape follow-on behaviors, including requesting all or specific objects from cloud storage. Similar to File and Directory Discovery on a local host, after identifying available storage services (i.e. Cloud Infrastructure Discovery) adversaries may access the contents/objects stored in cloud infrastructure. Cloud service providers offer APIs allowing users to enumerate objects stored within cloud storage. Examples include ListObjectsV2 in AWS (Citation: ListObjectsV2) and List Blobs in Azure(Citation: List Blobs) .

Adversaries may reflectively load code into a process in order to conceal the execution of malicious payloads. Reflective loading involves allocating then executing payloads directly within the memory of the process, vice creating a thread or process backed by a file path on disk (e.g., Shared Modules). Reflectively loaded payloads may be compiled binaries, anonymous files (only present in RAM), or just snubs of fileless executable code (ex: position-independent shellcode).(Citation: Introducing Donut)(Citation: S1 Custom Shellcode Tool)(Citation: Stuart ELF Memory)(Citation: 00sec Droppers)(Citation: Mandiant BYOL) For example, the `Assembly.Load()` method executed by PowerShell may be abused to load raw code into the running process.(Citation: Microsoft AssemblyLoad) Reflective code injection is very similar to Process Injection except that the “injection” loads code into the processes’ own memory instead of that of a separate process. Reflective loading may evade process-based detections since the execution of the arbitrary code may be masked within a legitimate or otherwise benign process. Reflectively loading payloads directly into memory may also avoid creating files or other artifacts on disk, while also enabling malware to keep these payloads encrypted (or otherwise obfuscated) until execution.(Citation: Stuart ELF Memory)(Citation: 00sec Droppers)(Citation: Intezer ACBackdoor)(Citation: S1 Old Rat New Tricks)

Adversaries may attempt to bypass multi-factor authentication (MFA) mechanisms and gain access to accounts by generating MFA requests sent to users. Adversaries in possession of credentials to Valid Accounts may be unable to complete the login process if they lack access to the 2FA or MFA mechanisms required as an additional credential and security control. To circumvent this, adversaries may abuse the automatic generation of push notifications to MFA services such as Duo Push, Microsoft Authenticator, Okta, or similar services to have the user grant access to their account. If adversaries lack credentials to victim accounts, they may also abuse automatic push notification generation when this option is configured for self-service password reset (SSPR).(Citation: Obsidian SSPR Abuse 2023) In some cases, adversaries may continuously repeat login attempts in order to bombard users with MFA push notifications, SMS messages, and phone calls, potentially resulting in the user finally accepting the authentication request in response to “MFA fatigue.”(Citation: Russian 2FA Push Annoyance - Cimpanu)(Citation: MFA Fatigue Attacks - PortSwigger)(Citation: Suspected Russian Activity Targeting Government and Business Entities Around the Globe)

Adversaries may employ various means to detect and avoid debuggers. Debuggers are typically used by defenders to trace and/or analyze the execution of potential malware payloads.(Citation: ProcessHacker Github) Debugger evasion may include changing behaviors based on the results of the checks for the presence of artifacts indicative of a debugged environment. Similar to Virtualization/Sandbox Evasion, if the adversary detects a debugger, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for debugger artifacts before dropping secondary or additional payloads. Specific checks will vary based on the target and/or adversary. On Windows, this may involve Native API function calls such as <code>IsDebuggerPresent()</code> and <code> NtQueryInformationProcess()</code>, or manually checking the <code>BeingDebugged</code> flag of the Process Environment Block (PEB). On Linux, this may involve querying `/proc/self/status` for the `TracerPID` field, which indicates whether or not the process is being traced by dynamic analysis tools.(Citation: Cado Security P2PInfect 2023)(Citation: Positive Technologies Hellhounds 2023) Other checks for debugging artifacts may also seek to enumerate hardware breakpoints, interrupt assembly opcodes, time checks, or measurements if exceptions are raised in the current process (assuming a present debugger would “swallow” or handle the potential error).(Citation: hasherezade debug)(Citation: AlKhaser Debug)(Citation: vxunderground debug) Malware may also leverage Structured Exception Handling (SEH) to detect debuggers by throwing an exception and detecting whether the process is suspended. SEH handles both hardware and software expectations, providing control over the exceptions including support for debugging. If a debugger is present, the program’s control will be transferred to the debugger, and the execution of the code will be suspended. If the debugger is not present, control will be transferred to the SEH handler, which will automatically handle the exception and allow the program’s execution to continue.(Citation: Apriorit) Adversaries may use the information learned from these debugger checks during automated discovery to shape follow-on behaviors. Debuggers can also be evaded by detaching the process or flooding debug logs with meaningless data via messages produced by looping Native API function calls such as <code>OutputDebugStringW()</code>.(Citation: wardle evilquest partii)(Citation: Checkpoint Dridex Jan 2021)

Adversaries may modify property list files (plist files) to enable other malicious activity, while also potentially evading and bypassing system defenses. macOS applications use plist files, such as the <code>info.plist</code> file, to store properties and configuration settings that inform the operating system how to handle the application at runtime. Plist files are structured metadata in key-value pairs formatted in XML based on Apple's Core Foundation DTD. Plist files can be saved in text or binary format.(Citation: fileinfo plist file description) Adversaries can modify key-value pairs in plist files to influence system behaviors, such as hiding the execution of an application (i.e. Hidden Window) or running additional commands for persistence (ex: Launch Agent/Launch Daemon or Re-opened Applications). For example, adversaries can add a malicious application path to the `~/Library/Preferences/com.apple.dock.plist` file, which controls apps that appear in the Dock. Adversaries can also modify the <code>LSUIElement</code> key in an application’s <code>info.plist</code> file to run the app in the background. Adversaries can also insert key-value pairs to insert environment variables, such as <code>LSEnvironment</code>, to enable persistence via Dynamic Linker Hijacking.(Citation: wardle chp2 persistence)(Citation: eset_osx_flashback)

Adversaries may abuse serverless computing, integration, and automation services to execute arbitrary code in cloud environments. Many cloud providers offer a variety of serverless resources, including compute engines, application integration services, and web servers. Adversaries may abuse these resources in various ways as a means of executing arbitrary commands. For example, adversaries may use serverless functions to execute malicious code, such as crypto-mining malware (i.e. Resource Hijacking).(Citation: Cado Security Denonia) Adversaries may also create functions that enable further compromise of the cloud environment. For example, an adversary may use the `IAM:PassRole` permission in AWS or the `iam.serviceAccounts.actAs` permission in Google Cloud to add Additional Cloud Roles to a serverless cloud function, which may then be able to perform actions the original user cannot.(Citation: Rhino Security Labs AWS Privilege Escalation)(Citation: Rhingo Security Labs GCP Privilege Escalation) Serverless functions can also be invoked in response to cloud events (i.e. Event Triggered Execution), potentially enabling persistent execution over time. For example, in AWS environments, an adversary may create a Lambda function that automatically adds Additional Cloud Credentials to a user and a corresponding CloudWatch events rule that invokes that function whenever a new user is created.(Citation: Backdooring an AWS account) This is also possible in many cloud-based office application suites. For example, in Microsoft 365 environments, an adversary may create a Power Automate workflow that forwards all emails a user receives or creates anonymous sharing links whenever a user is granted access to a document in SharePoint.(Citation: Varonis Power Automate Data Exfiltration)(Citation: Microsoft DART Case Report 001) In Google Workspace environments, they may instead create an Apps Script that exfiltrates a user's data when they open a file.(Citation: Cloud Hack Tricks GWS Apps Script)(Citation: OWN-CERT Google App Script 2024)

Adversaries may steal or forge certificates used for authentication to access remote systems or resources. Digital certificates are often used to sign and encrypt messages and/or files. Certificates are also used as authentication material. For example, Entra ID device certificates and Active Directory Certificate Services (AD CS) certificates bind to an identity and can be used as credentials for domain accounts.(Citation: O365 Blog Azure AD Device IDs)(Citation: Microsoft AD CS Overview) Authentication certificates can be both stolen and forged. For example, AD CS certificates can be stolen from encrypted storage (in the Registry or files)(Citation: APT29 Deep Look at Credential Roaming), misplaced certificate files (i.e. Unsecured Credentials), or directly from the Windows certificate store via various crypto APIs.(Citation: SpecterOps Certified Pre Owned)(Citation: GitHub CertStealer)(Citation: GitHub GhostPack Certificates) With appropriate enrollment rights, users and/or machines within a domain can also request and/or manually renew certificates from enterprise certificate authorities (CA). This enrollment process defines various settings and permissions associated with the certificate. Of note, the certificate’s extended key usage (EKU) values define signing, encryption, and authentication use cases, while the certificate’s subject alternative name (SAN) values define the certificate owner’s alternate names.(Citation: Medium Certified Pre Owned) Abusing certificates for authentication credentials may enable other behaviors such as Lateral Movement. Certificate-related misconfigurations may also enable opportunities for Privilege Escalation, by way of allowing users to impersonate or assume privileged accounts or permissions via the identities (SANs) associated with a certificate. These abuses may also enable Persistence via stealing or forging certificates that can be used as Valid Accounts for the duration of the certificate's validity, despite user password resets. Authentication certificates can also be stolen and forged for machine accounts. Adversaries who have access to root (or subordinate) CA certificate private keys (or mechanisms protecting/managing these keys) may also establish Persistence by forging arbitrary authentication certificates for the victim domain (known as “golden” certificates).(Citation: Medium Certified Pre Owned) Adversaries may also target certificates and related services in order to access other forms of credentials, such as Golden Ticket ticket-granting tickets (TGT) or NTLM plaintext.(Citation: Medium Certified Pre Owned)

Adversaries may purchase or otherwise acquire an existing access to a target system or network. A variety of online services and initial access broker networks are available to sell access to previously compromised systems.(Citation: Microsoft Ransomware as a Service)(Citation: CrowdStrike Access Brokers)(Citation: Krebs Access Brokers Fortune 500) In some cases, adversary groups may form partnerships to share compromised systems with each other.(Citation: CISA Karakurt 2022) Footholds to compromised systems may take a variety of forms, such as access to planted backdoors (e.g., Web Shell) or established access via External Remote Services. In some cases, access brokers will implant compromised systems with a “load” that can be used to install additional malware for paying customers.(Citation: Microsoft Ransomware as a Service) By leveraging existing access broker networks rather than developing or obtaining their own initial access capabilities, an adversary can potentially reduce the resources required to gain a foothold on a target network and focus their efforts on later stages of compromise. Adversaries may prioritize acquiring access to systems that have been determined to lack security monitoring or that have high privileges, or systems that belong to organizations in a particular sector.(Citation: Microsoft Ransomware as a Service)(Citation: CrowdStrike Access Brokers) In some cases, purchasing access to an organization in sectors such as IT contracting, software development, or telecommunications may allow an adversary to compromise additional victims via a Trusted Relationship, Multi-Factor Authentication Interception, or even Supply Chain Compromise. **Note:** while this technique is distinct from other behaviors such as Purchase Technical Data and Credentials, they may often be used in conjunction (especially where the acquired foothold requires Valid Accounts).

Adversaries may abuse cloud management services to execute commands within virtual machines. Resources such as AWS Systems Manager, Azure RunCommand, and Runbooks allow users to remotely run scripts in virtual machines by leveraging installed virtual machine agents. (Citation: AWS Systems Manager Run Command)(Citation: Microsoft Run Command) If an adversary gains administrative access to a cloud environment, they may be able to abuse cloud management services to execute commands in the environment’s virtual machines. Additionally, an adversary that compromises a service provider or delegated administrator account may similarly be able to leverage a Trusted Relationship to execute commands in connected virtual machines.(Citation: MSTIC Nobelium Oct 2021)

Adversaries may attempt to enumerate local device drivers on a victim host. Information about device drivers may highlight various insights that shape follow-on behaviors, such as the function/purpose of the host, present security tools (i.e. Security Software Discovery) or other defenses (e.g., Virtualization/Sandbox Evasion), as well as potential exploitable vulnerabilities (e.g., Exploitation for Privilege Escalation). Many OS utilities may provide information about local device drivers, such as `driverquery.exe` and the `EnumDeviceDrivers()` API function on Windows.(Citation: Microsoft Driverquery)(Citation: Microsoft EnumDeviceDrivers) Information about device drivers (as well as associated services, i.e., System Service Discovery) may also be available in the Registry.(Citation: Microsoft Registry Drivers) On Linux/macOS, device drivers (in the form of kernel modules) may be visible within `/dev` or using utilities such as `lsmod` and `modinfo`.(Citation: Linux Kernel Programming)(Citation: lsmod man)(Citation: modinfo man)

Adversaries may impair a system's ability to hibernate, reboot, or shut down in order to extend access to infected machines. When a computer enters a dormant state, some or all software and hardware may cease to operate which can disrupt malicious activity.(Citation: Sleep, shut down, hibernate) Adversaries may abuse system utilities and configuration settings to maintain access by preventing machines from entering a state, such as standby, that can terminate malicious activity.(Citation: Microsoft: Powercfg command-line options)(Citation: systemdsleep Linux) For example, `powercfg` controls all configurable power system settings on a Windows system and can be abused to prevent an infected host from locking or shutting down.(Citation: Two New Monero Malware Attacks Target Windows and Android Users) Adversaries may also extend system lock screen timeout settings.(Citation: BATLOADER: The Evasive Downloader Malware) Other relevant settings, such as disk and hibernate timeout, can be similarly abused to keep the infected machine running even if no user is active.(Citation: CoinLoader: A Sophisticated Malware Loader Campaign) Aware that some malware cannot survive system reboots, adversaries may entirely delete files used to invoke system shut down or reboot.(Citation: Condi-Botnet-binaries)

Adversaries may enumerate system and service logs to find useful data. These logs may highlight various types of valuable insights for an adversary, such as user authentication records (Account Discovery), security or vulnerable software (Software Discovery), or hosts within a compromised network (Remote System Discovery). Host binaries may be leveraged to collect system logs. Examples include using `wevtutil.exe` or PowerShell on Windows to access and/or export security event information.(Citation: WithSecure Lazarus-NoPineapple Threat Intel Report 2023)(Citation: Cadet Blizzard emerges as novel threat actor) In cloud environments, adversaries may leverage utilities such as the Azure VM Agent’s `CollectGuestLogs.exe` to collect security logs from cloud hosted infrastructure.(Citation: SIM Swapping and Abuse of the Microsoft Azure Serial Console) Adversaries may also target centralized logging infrastructure such as SIEMs. Logs may also be bulk exported and sent to adversary-controlled infrastructure for offline analysis. In addition to gaining a better understanding of the environment, adversaries may also monitor logs in real time to track incident response procedures. This may allow them to adjust their techniques in order to maintain persistence or evade defenses.(Citation: Permiso GUI-Vil 2023)

Adversaries may impersonate a trusted person or organization in order to persuade and trick a target into performing some action on their behalf. For example, adversaries may communicate with victims (via Phishing for Information, Phishing, or Internal Spearphishing) while impersonating a known sender such as an executive, colleague, or third-party vendor. Established trust can then be leveraged to accomplish an adversary’s ultimate goals, possibly against multiple victims. In many cases of business email compromise or email fraud campaigns, adversaries use impersonation to defraud victims -- deceiving them into sending money or divulging information that ultimately enables Financial Theft. Adversaries will often also use social engineering techniques such as manipulative and persuasive language in email subject lines and body text such as `payment`, `request`, or `urgent` to push the victim to act quickly before malicious activity is detected. These campaigns are often specifically targeted against people who, due to job roles and/or accesses, can carry out the adversary’s goal. Impersonation is typically preceded by reconnaissance techniques such as Gather Victim Identity Information and Gather Victim Org Information as well as acquiring infrastructure such as email domains (i.e. Domains) to substantiate their false identity.(Citation: CrowdStrike-BEC) There is the potential for multiple victims in campaigns involving impersonation. For example, an adversary may Compromise Accounts targeting one organization which can then be used to support impersonation against other entities.(Citation: VEC)

Adversaries may steal monetary resources from targets through extortion, social engineering, technical theft, or other methods aimed at their own financial gain at the expense of the availability of these resources for victims. Financial theft is the ultimate objective of several popular campaign types including extortion by ransomware,(Citation: FBI-ransomware) business email compromise (BEC) and fraud,(Citation: FBI-BEC) "pig butchering,"(Citation: wired-pig butchering) bank hacking,(Citation: DOJ-DPRK Heist) and exploiting cryptocurrency networks.(Citation: BBC-Ronin) Adversaries may Compromise Accounts to conduct unauthorized transfers of funds.(Citation: Internet crime report 2022) In the case of business email compromise or email fraud, an adversary may utilize Impersonation of a trusted entity. Once the social engineering is successful, victims can be deceived into sending money to financial accounts controlled by an adversary.(Citation: FBI-BEC) This creates the potential for multiple victims (i.e., compromised accounts as well as the ultimate monetary loss) in incidents involving financial theft.(Citation: VEC) Extortion by ransomware may occur, for example, when an adversary demands payment from a victim after Data Encrypted for Impact (Citation: NYT-Colonial) and Exfiltration of data, followed by threatening to leak sensitive data to the public unless payment is made to the adversary.(Citation: Mandiant-leaks) Adversaries may use dedicated leak sites to distribute victim data.(Citation: Crowdstrike-leaks) Due to the potentially immense business impact of financial theft, an adversary may abuse the possibility of financial theft and seeking monetary gain to divert attention from their true goals such as Data Destruction and business disruption.(Citation: AP-NotPetya)

Adversaries may gain access and continuously communicate with victims by injecting malicious content into systems through online network traffic. Rather than luring victims to malicious payloads hosted on a compromised website (i.e., Drive-by Target followed by Drive-by Compromise), adversaries may initially access victims through compromised data-transfer channels where they can manipulate traffic and/or inject their own content. These compromised online network channels may also be used to deliver additional payloads (i.e., Ingress Tool Transfer) and other data to already compromised systems.(Citation: ESET MoustachedBouncer) Adversaries may inject content to victim systems in various ways, including: * From the middle, where the adversary is in-between legitimate online client-server communications (**Note:** this is similar but distinct from Adversary-in-the-Middle, which describes AiTM activity solely within an enterprise environment) (Citation: Kaspersky Encyclopedia MiTM) * From the side, where malicious content is injected and races to the client as a fake response to requests of a legitimate online server (Citation: Kaspersky ManOnTheSide) Content injection is often the result of compromised upstream communication channels, for example at the level of an internet service provider (ISP) as is the case with "lawful interception."(Citation: Kaspersky ManOnTheSide)(Citation: ESET MoustachedBouncer)(Citation: EFF China GitHub Attack)

Adversaries may manipulate network traffic in order to hide and evade detection of their C2 infrastructure. This can be accomplished by identifying and filtering traffic from defensive tools,(Citation: TA571) masking malicious domains to obfuscate the true destination from both automated scanning tools and security researchers,(Citation: Schema-abuse)(Citation: Facad1ng)(Citation: Browser-updates) and otherwise hiding malicious artifacts to delay discovery and prolong the effectiveness of adversary infrastructure that could otherwise be identified, blocked, or taken down entirely. C2 networks may include the use of Proxy or VPNs to disguise IP addresses, which can allow adversaries to blend in with normal network traffic and bypass conditional access policies or anti-abuse protections. For example, an adversary may use a virtual private cloud to spoof their IP address to closer align with a victim's IP address ranges. This may also bypass security measures relying on geolocation of the source IP address.(Citation: sysdig)(Citation: Orange Residential Proxies) Adversaries may also attempt to filter network traffic in order to evade defensive tools in numerous ways, including blocking/redirecting common incident responder or security appliance user agents.(Citation: mod_rewrite)(Citation: SocGholish-update) Filtering traffic based on IP and geo-fencing may also avoid automated sandboxing or researcher activity (i.e., Virtualization/Sandbox Evasion).(Citation: TA571)(Citation: mod_rewrite) Hiding C2 infrastructure may also be supported by Resource Development activities such as Acquire Infrastructure and Compromise Infrastructure. For example, using widely trusted hosting services or domains such as prominent URL shortening providers or marketing services for C2 networks may enable adversaries to present benign content that later redirects victims to malicious web pages or infrastructure once specific conditions are met.(Citation: StarBlizzard)(Citation: QR-cofense)

Adversaries may attempt to modify hierarchical structures in infrastructure-as-a-service (IaaS) environments in order to evade defenses. IaaS environments often group resources into a hierarchy, enabling improved resource management and application of policies to relevant groups. Hierarchical structures differ among cloud providers. For example, in AWS environments, multiple accounts can be grouped under a single organization, while in Azure environments, multiple subscriptions can be grouped under a single management group.(Citation: AWS Organizations)(Citation: Microsoft Azure Resources) Adversaries may add, delete, or otherwise modify resource groups within an IaaS hierarchy. For example, in Azure environments, an adversary who has gained access to a Global Administrator account may create new subscriptions in which to deploy resources. They may also engage in subscription hijacking by transferring an existing pay-as-you-go subscription from a victim tenant to an adversary-controlled tenant. This will allow the adversary to use the victim’s compute resources without generating logs on the victim tenant.(Citation: Microsoft Peach Sandstorm 2023)(Citation: Microsoft Subscription Hijacking 2022) In AWS environments, adversaries with appropriate permissions in a given account may call the `LeaveOrganization` API, causing the account to be severed from the AWS Organization to which it was tied and removing any Service Control Policies, guardrails, or restrictions imposed upon it by its former Organization. Alternatively, adversaries may call the `CreateAccount` API in order to create a new account within an AWS Organization. This account will use the same payment methods registered to the payment account but may not be subject to existing detections or Service Control Policies.(Citation: AWS RE:Inforce Threat Detection 2024)

Adversaries may flood targeted email addresses with an overwhelming volume of messages. This may bury legitimate emails in a flood of spam and disrupt business operations.(Citation: sophos-bombing)(Citation: krebs-email-bombing) An adversary may accomplish email bombing by leveraging an automated bot to register a targeted address for e-mail lists that do not validate new signups, such as online newsletters. The result can be a wave of thousands of e-mails that effectively overloads the victim’s inbox.(Citation: krebs-email-bombing)(Citation: hhs-email-bombing) By sending hundreds or thousands of e-mails in quick succession, adversaries may successfully divert attention away from and bury legitimate messages including security alerts, daily business processes like help desk tickets and client correspondence, or ongoing scams.(Citation: hhs-email-bombing) This behavior can also be used as a tool of harassment.(Citation: krebs-email-bombing) This behavior may be a precursor for Spearphishing Voice. For example, an adversary may email bomb a target and then follow up with a phone call to fraudulently offer assistance. This social engineering may lead to the use of Remote Access Software to steal credentials, deploy ransomware, conduct Financial Theft(Citation: sophos-bombing), or engage in other malicious activity.(Citation: rapid7-email-bombing)

Adversaries who successfully compromise a system may attempt to maintain persistence by “closing the door” behind them – in other words, by preventing other threat actors from initially accessing or maintaining a foothold on the same system. For example, adversaries may patch a vulnerable, compromised system(Citation: Mandiant-iab-control)(Citation: CERT AT Fortinent Ransomware 2025) to prevent other threat actors from leveraging that vulnerability in the future. They may “close the door” in other ways, such as disabling vulnerable services(Citation: sophos-multiple-attackers), stripping privileges from accounts(Citation: aquasec-postgres-processes), or removing other malware already on the compromised device.(Citation: fsecure-netsky) Hindering other threat actors may allow an adversary to maintain sole access to a compromised system or network. This prevents the threat actor from needing to compete with or even being removed themselves by other threat actors. It also reduces the “noise” in the environment, lowering the possibility of being caught and evicted by defenders. Finally, in the case of Resource Hijacking, leveraging a compromised device’s full power allows the threat actor to maximize profit.(Citation: sophos-multiple-attackers)

Adversaries may gain initial access to target systems by connecting to wireless networks. They may accomplish this by exploiting open Wi-Fi networks used by target devices or by accessing secured Wi-Fi networks — requiring Valid Accounts — belonging to a target organization.(Citation: DOJ GRU Charges 2018)(Citation: Nearest Neighbor Volexity) Establishing a connection to a Wi-Fi access point requires a certain level of proximity to both discover and maintain a stable network connection. Adversaries may establish a wireless connection through various methods, such as by physically positioning themselves near a Wi-Fi network to conduct close access operations. To bypass the need for physical proximity, adversaries may attempt to remotely compromise nearby third-party systems that have both wired and wireless network connections available (i.e., dual-homed systems). These third-party compromised devices can then serve as a bridge to connect to a target’s Wi-Fi network.(Citation: Nearest Neighbor Volexity) Once an initial wireless connection is achieved, adversaries may leverage this access for follow-on activities in the victim network or further targeting of specific devices on the network. Adversaries may perform Network Sniffing or Adversary-in-the-Middle activities for Credential Access or Discovery.

Adversaries may achieve persistence by leveraging OAuth application integrations in a software-as-a-service environment. Adversaries may create a custom application, add a legitimate application into the environment, or even co-opt an existing integration to achieve malicious ends.(Citation: Push Security SaaS Persistence 2022)(Citation: SaaS Attacks GitHub Evil Twin Integrations) OAuth is an open standard that allows users to authorize applications to access their information on their behalf. In a SaaS environment such as Microsoft 365 or Google Workspace, users may integrate applications to improve their workflow and achieve tasks. Leveraging application integrations may allow adversaries to persist in an environment – for example, by granting consent to an application from a high-privileged adversary-controlled account in order to maintain access to its data, even in the event of losing access to the account.(Citation: Wiz Midnight Blizzard 2024)(Citation: Microsoft Malicious OAuth Applications 2022)(Citation: Huntress Persistence Microsoft 365 Compromise 2024) In some cases, integrations may remain valid even after the original consenting user account is disabled.(Citation: Push Security Slack Persistence 2023) Application integrations may also allow adversaries to bypass multi-factor authentication requirements through the use of Application Access Tokens. Finally, they may enable persistent Automated Exfiltration over time.(Citation: Synes Cyber Corner Malicious Azure Application 2023) Creating or adding a new application may require the adversary to create a dedicated Cloud Account for the application and assign it Additional Cloud Roles – for example, in Microsoft 365 environments, an application can only access resources via an associated service principal.(Citation: Microsoft Entra ID Service Principals)

Adversaries may fake, or spoof, a sender’s identity by modifying the value of relevant email headers in order to establish contact with victims under false pretenses.(Citation: Proofpoint TA427 April 2024) In addition to actual email content, email headers (such as the FROM header, which contains the email address of the sender) may also be modified. Email clients display these headers when emails appear in a victim's inbox, which may cause modified emails to appear as if they were from the spoofed entity. This behavior may succeed when the spoofed entity either does not enable or enforce identity authentication tools such as Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and/or Domain-based Message Authentication, Reporting and Conformance (DMARC).(Citation: Cloudflare DMARC, DKIM, and SPF)(Citation: DMARC-overview)(Citation: Proofpoint-DMARC) Even if SPF and DKIM are configured properly, spoofing may still succeed when a domain sets a weak DMARC policy such as `v=DMARC1; p=none; fo=1;`. This means that while DMARC is technically present, email servers are not instructed to take any filtering action when emails fail authentication checks.(Citation: Proofpoint TA427 April 2024)(Citation: ic3-dprk) Adversaries may abuse Microsoft 365’s Direct Send functionality to spoof internal users by using internal devices like printers to send emails without authentication.(Citation: Barnea DirectSend) Adversaries may also abuse absent or weakly configured SPF, SKIM, and/or DMARC policies to conceal social engineering attempts(Citation: ic3-dprk) such as Phishing. They may also leverage email spoofing for Impersonation of legitimate external individuals and organizations, such as journalists and academics.(Citation: ic3-dprk)

An adversary may attempt to enumerate running virtual machines (VMs) after gaining access to a host or hypervisor. For example, adversaries may enumerate a list of VMs on an ESXi hypervisor using a Hypervisor CLI such as `esxcli` or `vim-cmd` (e.g. `esxcli vm process list or vim-cmd vmsvc/getallvms`).(Citation: Crowdstrike Hypervisor Jackpotting Pt 2 2021)(Citation: TrendMicro Play) Adversaries may also directly leverage a graphical user interface, such as VMware vCenter, in order to view virtual machines on a host. Adversaries may use the information from Virtual Machine Discovery during discovery to shape follow-on behaviors. Subsequently discovered VMs may be leveraged for follow-on activities such as Service Stop or Data Encrypted for Impact.(Citation: Crowdstrike Hypervisor Jackpotting Pt 2 2021)

Adversaries may simulate keystrokes on a victim’s computer by various means to perform any type of action on behalf of the user, such as launching the command interpreter using keyboard shortcuts, typing an inline script to be executed, or interacting directly with a GUI-based application. These actions can be preprogrammed into adversary tooling or executed through physical devices such as Human Interface Devices (HIDs). For example, adversaries have used tooling that monitors the Windows message loop to detect when a user visits bank-specific URLs. If detected, the tool then simulates keystrokes to open the developer console or select the address bar, pastes malicious JavaScript from the clipboard, and executes it - enabling manipulation of content within the browser, such as replacing bank account numbers during transactions.(Citation: BleepingComputer BackSwap)(Citation: welivesecurity BackSwap) Adversaries have also used malicious USB devices to emulate keystrokes that launch PowerShell, leading to the download and execution of malware from adversary-controlled servers.(Citation: BleepingComputer USB)

Adversaries may abuse ESXi administration services to execute commands on guest machines hosted within an ESXi virtual environment. Persistent background services on ESXi-hosted VMs, such as the VMware Tools Daemon Service, allow for remote management from the ESXi server. The tools daemon service runs as `vmtoolsd.exe` on Windows guest operating systems, `vmware-tools-daemon` on macOS, and `vmtoolsd ` on Linux.(Citation: Broadcom VMware Tools Services) Adversaries may leverage a variety of tools to execute commands on ESXi-hosted VMs – for example, by using the vSphere Web Services SDK to programmatically execute commands and scripts via APIs such as `StartProgramInGuest`, `ListProcessesInGuest`, `ListFileInGuest`, and `InitiateFileTransferFromGuest`.(Citation: Google Cloud Threat Intelligence VMWare ESXi Zero-Day 2023)(Citation: Broadcom Running Guest OS Operations) This may enable follow-on behaviors on the guest VMs, such as File and Directory Discovery, Data from Local System, or OS Credential Dumping.

Adversaries may manipulate continuous integration / continuous development (CI/CD) processes by injecting malicious code into the build process. There are several mechanisms for poisoning pipelines: * In a <b>Direct Pipeline Execution</b> scenario, the threat actor directly modifies the CI configuration file (e.g., `gitlab-ci.yml` in GitLab). They may include a command to exfiltrate credentials leveraged in the build process to a remote server, or to export them as a workflow artifact.(Citation: Unit 42 Palo Alto GitHub Actions Supply Chain Attack 2025)(Citation: OWASP CICD-SEC-4) * In an <b>Indirect Pipeline Execution</b> scenario, the threat actor injects malicious code into files referenced by the CI configuration file. These may include makefiles, scripts, unit tests, and linters.(Citation: OWASP CICD-SEC-4) * In a <b>Public Pipeline Execution</b> scenario, the threat actor does not have direct access to the repository but instead creates a malicious pull request from a fork that triggers a part of the CI/CD pipeline. For example, in GitHub Actions, the `pull_request_target` trigger allows workflows running from forked repositories to access secrets. If this trigger is combined with an explicit pull request checkout and a location for a threat actor to insert malicious code (e.g., an `npm build` command), a threat actor may be able to leak pipeline credentials.(Citation: Unit 42 Palo Alto GitHub Actions Supply Chain Attack 2025)(Citation: GitHub Security Lab GitHub Actions Security 2021) Similarly, threat actors may craft pull requests with malicious inputs (such as branch names) if the build pipeline treats those inputs as trusted.(Citation: Wiz Ultralytics AI Library Hijack 2024)(Citation: Synactiv Hijacking GitHub Runners)(Citation: GitHub Security Labs GitHub Actions Security Part 2 2021) Finally, if a pipeline leverages a self-hosted runner, a threat actor may be able to execute arbitrary code on a host inside the organization’s network.(Citation: John Stawinski PyTorch Supply Chain Attack 2024) By poisoning CI/CD pipelines, threat actors may be able to gain access to credentials, laterally move to additional hosts, or input malicious components to be shipped further down the pipeline (i.e., Supply Chain Compromise).

Adversaries may employ various time-based methods to evade detection and analysis. These techniques often exploit system clocks, delays, or timing mechanisms to obscure malicious activity, blend in with benign activity, and avoid scrutiny. Adversaries can perform this behavior within virtualization/sandbox environments or natively on host systems. Adversaries may utilize programmatic `sleep` commands or native system scheduling functionality, for example Scheduled Task/Job. Benign commands or other operations may also be used to delay malware execution or ensure prior commands have had time to execute properly. Loops or otherwise needless repetitions of commands, such as `ping`, may be used to delay malware execution and potentially exceed time thresholds of automated analysis environments.(Citation: Revil Independence Day)(Citation: Netskope Nitol) Another variation, commonly referred to as API hammering, involves making various calls to Native API functions in order to delay execution (while also potentially overloading analysis environments with junk data).(Citation: Joe Sec Nymaim)(Citation: Joe Sec Trickbot)

Adversaries may intentionally exclude certain files, folders, directories, file types, or system components from encryption or tampering during a ransomware or malicious payload execution. Some file extensions that adversaries may avoid encrypting include `.dll`, `.exe`, and `.lnk`.(Citation: Palo Alto Unit 42 Medusa Group Medusa Ransomware January 2024) Adversaries may perform this behavior to avoid alerting users, to evade detection by security tools and analysts, or, in the case of ransomware, to ensure that the system remains operational enough to deliver the ransom notice. Exclusions may target files and components whose corruption would cause instability, break core services, or immediately expose the attack. By carefully avoiding these areas, adversaries maintain system responsiveness while minimizing indicators that could trigger alarms or otherwise inhibit achieving their goals.

Adversaries may enumerate local drives, disks, and/or volumes and their attributes like total or free space and volume serial number. This can be done to prepare for ransomware-related encryption, to perform Lateral Movement, or as a precursor to Direct Volume Access. On ESXi systems, adversaries may use Hypervisor CLI commands such as `esxcli` to list storage connected to the host as well as `.vmdk` files.(Citation: TrendMicro)(Citation: TrendMicro ESXI Ransomware) On Windows systems, adversaries can use `wmic logicaldisk get` to find information about local network drives. They can also use `Get-PSDrive` in PowerShell to retrieve drives and may additionally use Windows API functions such as `GetDriveType`.(Citation: Trend Micro MUSTANG PANDA PUBLOAD HIUPAN SEPTEMBER 2024)(Citation: Volexity) Linux has commands such as `parted`, `lsblk`, `fdisk`, `lshw`, and `df` that can list information about disk partitions such as size, type, file system types, and free space. The command `diskutil` on MacOS can be used to list disks while `system_profiler SPStorageDataType` can additionally show information such as a volume’s mount path, file system, and the type of drive in the system. Infrastructure as a Service (IaaS) cloud providers also have commands for storage discovery such as `describe volume` in AWS, `gcloud compute disks list` in GCP, and `az disk list` in Azure.(Citation: AWS docs describe volumes)(Citation: GCP gcloud compute disks list)(Citation: azure az disk)

Threat actors may seek information/indicators from closed or open threat intelligence sources gathered about their own campaigns, as well as those conducted by other adversaries that may align with their target industries, capabilities/objectives, or other operational concerns. These reports may include descriptions of behavior, detailed breakdowns of attacks, atomic indicators such as malware hashes or IP addresses, timelines of a group’s activity, and more. Adversaries may change their behavior when planning their future operations. Adversaries have been observed replacing atomic indicators mentioned in blog posts in under a week.(Citation: Google Cloud Threat Intelligence VMWare ESXi Zero-Day 2023) Adversaries have also been seen searching for their own domain names in threat vendor data and then taking them down, likely to avoid seizure or further investigation.(Citation: Sentinel One Contagious Interview ClickFix September 2025) This technique is distinct from Threat Intel Vendors in that it describes threat actors performing reconnaissance on their own activity, not in search of victim information.