Performing Privilege Escalation on Linux Skill

Performing Privilege Escalation on Linux

Legal Notice: This skill is for authorized security testing and educational purposes only. Unauthorized use against systems you do not own or have written permission to test is illegal and may violate computer fraud laws.

Overview

Linux privilege escalation involves elevating from a low-privilege user account to root access on a compromised system. Red teams exploit misconfigurations, vulnerable services, kernel exploits, and weak permissions to achieve root. This skill covers both manual enumeration techniques and automated tools for identifying and exploiting privilege escalation vectors.

When to Use

When conducting security assessments that involve performing privilege escalation on linux
When following incident response procedures for related security events
When performing scheduled security testing or auditing activities
When validating security controls through hands-on testing

Prerequisites

Familiarity with red teaming concepts and tools
Access to a test or lab environment for safe execution
Python 3.8+ with required dependencies installed
Appropriate authorization for any testing activities

MITRE ATT&CK Mapping

T1548.001 - Abuse Elevation Control Mechanism: Setuid and Setgid
T1548.003 - Abuse Elevation Control Mechanism: Sudo and Sudo Caching
T1068 - Exploitation for Privilege Escalation
T1574.006 - Hijack Execution Flow: Dynamic Linker Hijacking
T1053.003 - Scheduled Task/Job: Cron
T1543.002 - Create or Modify System Process: Systemd Service

Key Escalation Vectors

SUID/SGID Binaries

Find SUID binaries: find / -perm -4000 -type f 2>/dev/null
Check GTFOBins for exploitation methods
Custom SUID binaries may have vulnerabilities

Sudo Misconfigurations

sudo -l to list allowed commands
Wildcards in sudo rules allow injection
NOPASSWD entries for dangerous commands
sudo versions vulnerable to CVE-2021-3156 (Baron Samedit)

Kernel Exploits

Dirty Cow (CVE-2016-5195) for older kernels
Dirty Pipe (CVE-2022-0847) for kernel 5.8+
PwnKit (CVE-2021-4034) for pkexec
GameOver(lay) (CVE-2023-2640, CVE-2023-32629) for Ubuntu

Cron Job Abuse

World-writable cron scripts
PATH hijacking in cron jobs
Wildcard injection in cron commands

Capabilities

getcap -r / 2>/dev/null to find binaries with capabilities
cap_setuid allows UID manipulation
cap_dac_override bypasses file permissions

Writable Service Files

Systemd unit files with weak permissions
Init scripts writable by non-root users
Socket files in accessible locations

Tools and Resources

| Tool | Purpose | |------|---------| | LinPEAS | Automated privilege escalation enumeration | | LinEnum | Linux enumeration script | | linux-exploit-suggester | Kernel exploit matching | | pspy | Process monitoring without root | | GTFOBins | SUID/sudo binary exploitation reference | | PEASS-ng | Privilege escalation awesome scripts suite |

Validation Criteria

[ ] Enumeration performed using automated tools
[ ] Privilege escalation vector identified
[ ] Root access achieved through identified vector
[ ] Evidence documented (screenshots, command output)
[ ] Alternative escalation paths identified

Agent Skills: Performing Privilege Escalation on Linux

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