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TryHackMe Writeup: Blog

·211 words·1 min

Executive Summary
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Technical security assessment conducted under the NIST SP 800-115 framework. The host running WordPress exhibited weaknesses in authentication policies, allowing RCE via malicious upload. Privilege escalation exploited a lack of environment variable sanitization in a custom binary, resulting in full system compromise.

Attack Chain (PTES Mapping)
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1. Pre-engagement & Intelligence Gathering
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Attack surface mapping performed via Nmap.

sudo nmap -Pn -sS -sV -T4 -p- 10.64.131.151
  • MITRE Technique: T1595 - Active Scanning.

2. Vulnerability Analysis
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CMS enumeration identified valid users bjoel and kwheel. A critical vulnerability was found in the password policy.

wpscan --url [http://10.64.131.151](http://10.64.131.151) --usernames kwheel --passwords rockyou.txt
  • MITRE Technique: T1110.001 - Brute Force: Password Cracking.

3. Exploitation (Initial Access)
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Using the discovered credentials kwheel:cutiepie1, a web shell was successfully uploaded to the server.

  • MITRE Technique: T1505.003 - Server Software Component: Web Shell.

4. Post-Exploitation (Privilege Escalation)
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A custom SUID binary located at /usr/sbin/checker was identified. Exploitation involved environment variable injection, allowing arbitrary code execution as root.

export admin=1 && /usr/sbin/checker
  • MITRE Technique: T1548.001 - Abuse Elevation Control Mechanism: Setuid and Setgid.

Recommendations (NIST SP 800-115)
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  • Access Control: Implement MFA and account lockout policies for WordPress.
  • System Integrity: Remove SUID bits from binaries that rely on unsanitized environment variables (chmod -s /usr/sbin/checker).
Enrico Moreno
Author
Enrico Moreno