
Summary
This detection rule identifies instances in which Windows executables attempt to write files with potentially suspicious extensions, which could indicate an evasion attempt by malware. The rule specifically focuses on executable images associated with critical Windows processes such as `csrss.exe`, `lsass.exe`, and `winlogon.exe`, among others. The targeted extensions for files being written include, but are not limited to, `.bat`, `.dll`, `.exe`, `.hta`, `.iso`, `.ps1`, `.txt`, `.vbe`, and `.vbs`. Additional filters narrow down the detection to instances that occur within specific directories that are commonly exploited by malicious actors, including user directories and temporary folders. By employing a conditional matching structure that necessitates the occurrence of either generic or special selection criteria while simultaneously excluding certain paths, the rule aims to minimize false positives and focus on suspicious activity likely indicative of a defense evasion tactic.
Categories
- Windows
- Endpoint
Data Sources
- File
Created: 2022-08-12