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DET0020 Detect Shell Configuration Modification for Persistence via Event-Triggered Execution

Item Value
ID DET0020
Version 1.0
Created 21 October 2025
Last Modified 21 October 2025

Technique Detected: T1546.004 (Unix Shell Configuration Modification)

Analytics

Linux

AN0059

Detects modification of shell startup/logout scripts such as ~/.bashrc, ~/.bash_profile, or /etc/profile, followed by anomalous process execution or network connections upon interactive or remote shell login.

Log Sources
Data Component Name Channel
File Modification (DC0061) auditd:SYSCALL AUDIT_SYSCALL (open, write, rename, unlink)
Process Creation (DC0032) auditd:EXECVE execution of unexpected binaries during user shell startup
Network Traffic Content (DC0085) NSM:Flow unexpected network activity initiated shortly after shell session starts
Mutable Elements
Field Description
TimeWindow Defines how soon after shell startup process execution or network activity is considered suspicious.
TargetUser Limits detection to specific user accounts or roles such as root or service accounts.
FilePathRegex Defines what shell configuration paths are considered relevant (e.g., .bashrc, .bash_logout, etc.)

macOS

AN0060

Correlates zsh shell configuration file changes (e.g., ~/.zshrc, ~/.zlogin, /etc/zprofile) with execution of unauthorized binaries or unexpected network activity triggered on Terminal.app launch.

Log Sources
Data Component Name Channel
Process Creation (DC0032) macos:unifiedlog launch of Terminal.app or shell with non-standard environment setup
File Modification (DC0061) macos:endpointsecurity ES_EVENT_TYPE_NOTIFY_WRITE, targeting .zshrc, .zlogin, .zprofile
Mutable Elements
Field Description
FileTargetList Customizable list of shell config files considered sensitive for detection.
PayloadEntropyThreshold Used to distinguish benign from potentially obfuscated commands written to config files.
UserContext Scoping based on user login class, e.g., administrative vs standard users.