Performing Privilege Escalation On Linux

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

Trigger phrases:

• "performing privilege escalation on linux"

• "Linux privilege escalation involves elevating from a low-privilege user account "

• 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

This section covers key escalation vectors for performing privilege escalation on linux.

• Ensure all prerequisites are met before proceeding
• Follow the documented workflow steps in sequence
• Record results and any anomalies encountered during this phase

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

When NOT to Use

• You don't have explicit written authorization to test
• Task is about defense/detection, not offense (use detection skills)
• You need to implement security controls (use implementing-* skills)
• Task requires compliance auditing (use auditing-* skills)
• You're investigating an incident (use incident response skills)
• Target is out of scope for your engagement
• Task is about vulnerability scanning only (use scanning tools)

Red Flags

• Performing actions without explicit written authorization from the asset owner
• Testing against production systems without a defined scope and rules of engagement
• Sharing sensitive findings or credentials in unencrypted communications
• Failing to properly scope and contain the assessment before starting

Verification

• All steps executed successfully against a test environment before production use
• Output documented with screenshots or logs demonstrating expected behavior
• Results validated against known-good baselines or reference implementations
• Documentation complete enough for another analyst to reproduce findings

Tools and Resources

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

Process

# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: str) -> dict:
    return {k: re.findall(v, text) for k, v in IOC_PATTERNS.items()}

1. Analyze the task requirements
2. Apply domain expertise
3. Verify output quality

Anti-Rationalization Table