analyzing-persistence-mechanisms-in-linux
Scan Linux systems for persistence mechanisms including crontab/systemd entries, LD_PRELOAD injection, shell profile modifications (.bashrc, .profile), and SSH authorized_keys backdoors, then correlate findings with auditd logs into an installation timeline. Use during incident response or threat hunting to detect or confirm how an adversary maintained access to a compromised Linux host.
How do I install this agent skill?
npx skills add https://github.com/mukul975/anthropic-cybersecurity-skills --skill analyzing-persistence-mechanisms-in-linuxIs this agent skill safe to install?
- Gen Agent Trust Hubpass
The skill is a security auditing tool designed to scan Linux systems for persistence mechanisms. It uses standard system commands to inspect configuration files and generates a technical report for threat hunting. No malicious behavior or data exfiltration was detected.
- Socketpass
No alerts
- Snykpass
Risk: LOW · No issues
What does this agent skill do?
Analyzing Persistence Mechanisms in Linux
Overview
Adversaries establish persistence on Linux systems through crontab jobs, systemd service/timer units, LD_PRELOAD library injection, shell profile modifications (.bashrc, .profile), SSH authorized_keys backdoors, and init script manipulation. This skill scans for all known persistence vectors, checks file timestamps and integrity, and correlates findings with auditd logs to build a timeline of persistence installation.
When to Use
- When investigating security incidents that require analyzing persistence mechanisms in linux
- When building detection rules or threat hunting queries for this domain
- When SOC analysts need structured procedures for this analysis type
- When validating security monitoring coverage for related attack techniques
Prerequisites
- Root or sudo access on target Linux system (or forensic image)
- auditd configured with file watch rules on persistence paths
- Python 3.8+ with standard library (os, subprocess, json)
- Optional: OSSEC/Wazuh agent for file integrity monitoring alerts
Steps
- Scan Crontab Entries — Enumerate all user crontabs, /etc/cron.d/, /etc/cron.daily/, and anacron jobs for suspicious commands
- Audit Systemd Units — Check /etc/systemd/system/ and ~/.config/systemd/user/ for non-package-managed service and timer units
- Detect LD_PRELOAD Hijacking — Check /etc/ld.so.preload and LD_PRELOAD environment variable for injected shared libraries
- Inspect Shell Profiles — Scan .bashrc, .bash_profile, .profile, /etc/profile.d/ for injected commands or reverse shells
- Check SSH Authorized Keys — Audit all authorized_keys files for unauthorized public keys with command restrictions
- Correlate Auditd Logs — Search auditd logs for file modification events on persistence paths to build an installation timeline
- Generate Persistence Report — Produce a risk-scored report of all discovered persistence mechanisms
Expected Output
- JSON report of all persistence mechanisms found with risk scores
- Timeline of persistence installation from auditd correlation
- MITRE ATT&CK technique mapping (T1053, T1543, T1574, T1546)
- Remediation commands for each detected persistence mechanism
How can the creator link this skill?
Add the canonical catalog link to the repository README so users can inspect current installs and available audits. The publishing guide covers the complete discovery path.
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