CVE-2025-57403
📋 TL;DR
Cola Dnslog v1.3.2 has a directory traversal vulnerability in TXT record processing that allows attackers to read arbitrary files on the server. This affects anyone running the vulnerable version of Cola Dnslog. Attackers can potentially access sensitive configuration files, credentials, or other system data.
💻 Affected Systems
- Cola Dnslog
📦 What is this software?
Cola Dnslog by Abelche
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise through reading sensitive files like SSH keys, database credentials, or configuration files containing secrets, potentially leading to lateral movement or data exfiltration.
Likely Case
Exposure of sensitive application files, configuration data, or system information that could be used for further attacks or reconnaissance.
If Mitigated
Limited to reading non-sensitive files if proper file permissions and access controls are implemented.
🎯 Exploit Status
The vulnerability requires only a specially crafted DNS TXT query. Public proof-of-concept exists in the GitHub issue.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch available. Consider upgrading to a newer version if available, or implement workarounds.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement proper input validation to reject directory traversal sequences in DNS queries.
Modify source code to validate and sanitize input before os.path.join operations
Web Application Firewall Rules
allConfigure WAF to block requests containing directory traversal patterns.
Add WAF rule to block patterns like '../', '..\', absolute paths
🧯 If You Can't Patch
- Restrict file system permissions to limit what files the application can access
- Implement network segmentation to isolate the DNSlog server from sensitive systems
🔍 How to Verify
Check if Vulnerable:
Test with a DNS TXT query containing directory traversal sequences (e.g., '../etc/passwd') and check if file contents are returned.Check Version:
Check the application version in the interface or configuration filesVerify Fix Applied:
Retest with the same traversal attempts after implementing fixes; queries should return errors or sanitized responses.📡 Detection & Monitoring
Log Indicators:
- DNS queries with unusual patterns containing '../', '..\', or absolute paths
- Multiple failed file access attempts from single source
Network Indicators:
- DNS TXT queries with suspicious path-like strings
- Unusual traffic patterns to DNSlog server
SIEM Query:
source="dnslog" AND query="*../*" OR query="*..\\*"