CVE-2020-26037
📋 TL;DR
This CVE describes a directory traversal vulnerability in Even Balance Punkbuster anti-cheat software that allows remote attackers to execute arbitrary code. The vulnerability affects servers running Punkbuster versions 1.902 through 1.904. Attackers can exploit this to gain unauthorized access and control over affected systems.
💻 Affected Systems
- Even Balance Punkbuster
📦 What is this software?
Punkbuster by Evenbalance
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with remote code execution, allowing attackers to install malware, steal data, or pivot to other systems.
Likely Case
Server compromise leading to game server manipulation, cheating facilitation, or denial of service attacks.
If Mitigated
Limited impact with proper network segmentation and access controls preventing exploitation attempts.
🎯 Exploit Status
Directory traversal vulnerabilities are typically straightforward to exploit. The Medium article reference suggests public exploitation details exist.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.905 or later
Vendor Advisory: http://punkbuster.com
Restart Required: Yes
Instructions:
1. Download Punkbuster version 1.905 or later from the official website. 2. Stop the Punkbuster service. 3. Install the updated version. 4. Restart the Punkbuster service. 5. Verify the version is 1.905 or higher.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to Punkbuster servers to only trusted game clients and administrative systems.
Firewall Rules
allImplement strict firewall rules limiting inbound connections to Punkbuster ports.
🧯 If You Can't Patch
- Isolate affected systems in a separate network segment with strict access controls
- Implement application-level firewalls or WAF rules to detect and block directory traversal attempts
🔍 How to Verify
Check if Vulnerable:
Check the Punkbuster version on your server. If it's between 1.902 and 1.904 inclusive, the system is vulnerable.Check Version:
On Windows: Check Punkbuster service properties or installation directory. On Linux: Check package version or run pb_sv_ver command if available.Verify Fix Applied:
Confirm the installed Punkbuster version is 1.905 or higher and test server functionality.📡 Detection & Monitoring
Log Indicators:
- Unusual file access patterns in Punkbuster logs
- Directory traversal strings in request logs
- Failed authentication attempts followed by file access attempts
Network Indicators:
- Unusual traffic patterns to Punkbuster ports
- Requests containing '../' sequences or other path traversal patterns
SIEM Query:
source="punkbuster.log" AND ("../" OR "..\\" OR "%2e%2e%2f" OR directory traversal patterns)