User Execution

What the technique is

An adversary may rely upon specific actions by a user in order to gain execution. Users may be subjected to social engineering to get them to execute malicious code by, for example, opening a malicious document file or link. These user actions will typically be observed as follow-on behavior from forms of Phishing. While User Execution frequently occurs shortly after Initial Access it may occur at other phases of an intrusion, such as when an adversary places a file in a shared directory or on a user's desktop hoping that a user will click on it. This activity may also be seen shortly after Internal Spearphishing. Adversaries may also deceive users into performing actions such as: Enabling Remote Access Tools, allowing direct control of the system to the adversary Running malicious JavaScript in their browser, allowing adversaries to Steal Web Session Cookies Downloading and executing malware for User Execution Coerceing users to copy, paste, and execute malicious code manually For example, tech support scams can be facilitated through Phishing, vishing, or various forms of user interaction. Adversaries can use a combination of these methods, such as spoofing and promoting toll-free numbers or call centers that are used to direct victims to malicious websites, to deliver and execute payloads containing malware or Remote Access Tools.

What MITRE says you would watch

• AN1314

  Cause→effect chain: (1) User-facing app (Office/PDF/archiver/browser) records an open/click or abnormal event, then (2) a downloaded file is created in a user-writable path and/or decompressed, (3) the parent user app spawns a living-off-the-land binary (e.g., powershell/cmd/mshta/rundll32/msiexec/wscript/expand/zip) or installer, and (4) immediate outbound HTTP(S)/DNS/SMB from the same lineage.

• AN1315

  Cause→effect chain: (1) User app/browser/archiver logs an open/click or abnormal exit, (2) new executable/script/archive extracted into $HOME/Downloads, /tmp, or ~/.cache, (3) parent app spawns shell/interpreter (bash/sh/python/node/curl/wget) or desktop file, and (4) new outbound connection(s) from the child lineage.

• AN1316

  Cause→effect chain: (1) unified logs show application open/click or crash for Safari/Chrome/Office/Preview/archiver, (2) file write/extraction into ~/Downloads, /private/var/folders/* or ~/Library, (3) parent app spawns osascript/bash/zsh/curl/python or opens a quarantined app with Gatekeeper prompts, (4) network egress from child.