Linux ln Command Exploit: How Symlink Race Conditions Lead to Root Privilege Escalation

🔴 Linux ln Command Exploit: How Symlink Race Conditions Lead to Root Privilege Escalation

Most devs think ln is just "create a link." Attackers know it as the tool behind one of the most persistent Linux privesc bugs in history: the symlink race condition (TOCTOU).

If a root-owned script writes to a predictable path (/tmp/.log, /var/run/.pid) without checking file type first, an attacker can swap that path for a symlink to /etc/passwd or a cron dir — and root writes exactly where the attacker wants.

This bug class has hit container runtimes, backup tools, and logging daemons in real CVEs.

📌 Full breakdown inside:

• Hard links vs symbolic links (security implications)
• Real-world symlink attack walkthrough
• auditd rules + log indicators for SOC detection
• Blue team defenses: FIM, symlink sweeps, behavioral correlation
• Hardening checklist to stop privilege escalation
• Complete ln command reference with security notes

Read the full guide 👉 https://www.xpert4cyber.com/2026/07/linux-ln-command-symlink-attack-hack-root.html