Pentest for Element Management System

The client required a comprehensive Linux privilege escalation assessment for a critical server within its VoIP carrier-grade communication environment. The goal was to identify system weaknesses that could be exploited by insider threats or attackers with limited access privileges.

Test Methodology

• Testing Approach: White-box assessment.
• Test Category: Linux System Security Testing.
• Objective: Identified potential privilege escalation paths, misconfigurations, insecure file permissions, and outdated packages that could enable unauthorized privilege gain or persistence.
• Tools Used:
  • Manual testing (Linux command-line techniques)
  • Automated enumeration frameworks:
    • LinPEAS
    • LinEnum
    • LSE (Linux Smart Enumeration)

Test Procedure

• System & User Enumeration
  • Collected detailed system information: kernel version, distribution, installed packages, and running services.
  • Verified current user privileges, group memberships, and accessible sudo commands.
  • Checked for vulnerable binaries in the user’s PATH.
• Misconfiguration Assessment
  • Searched for SUID binaries, world-writable files, and insecure cron jobs.
  • Audited environment variables (e.g., $PATH, $LD_PRELOAD) for insecure settings.
  • Evaluated service permissions, particularly custom monitoring daemons.
• Privilege Escalation & Exploit Simulation
  • Validated exploitation paths identified through enumeration.
  • Detected local privilege escalation exploits (e.g., PwnKit – CVE-2021-4034).
  • Found insecure cron jobs owned by root and weak file permission structures.
• Persistence Testing
  • Explored persistence mechanisms such as cron job injection, SSH key planting, and startup script modification.
• Sensitive Information Discovery
  • Reviewed directories (etc, /var, /opt/ems, /home) for readable config files and credentials.
  • Identified hardcoded API tokens, SNMP community strings, and topology files exposing internal data.

• Early Detection of Privilege Escalation Risks: Discovered and mitigated exploitable escalation paths before potential attackers could leverage them.
• Enhanced Linux System Hardening: Provided actionable remediation to improve kernel, service, and user-level security controls.
• Proactive Insider Threat Mitigation: Prevented privilege misuse and unauthorized persistence mechanisms by reinforcing secure configurations.
• Strengthened Compliance & Reliability: Aligned Linux host security with telecom-grade operational standards, ensuring system stability and continuous uptime.