CVE-2023-34303
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Ashlar-Vellum Cobalt installations by tricking users into opening malicious VC6 files. The flaw exists in improper validation of VC6 file data, leading to out-of-bounds reads that can be leveraged for code execution. Users of Ashlar-Vellum Cobalt who open untrusted VC6 files are affected.
💻 Affected Systems
- Ashlar-Vellum Cobalt
📦 What is this software?
Cobalt by Ashlar
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control of the affected system in the context of the current user, potentially leading to data theft, ransomware deployment, or lateral movement.
Likely Case
Attacker executes malicious code with the privileges of the user who opened the malicious file, potentially installing malware, stealing credentials, or accessing sensitive data.
If Mitigated
Limited impact due to proper file validation, user awareness training, and restricted user privileges preventing full system compromise.
🎯 Exploit Status
Exploitation requires user interaction but leverages common memory corruption techniques. ZDI advisory suggests weaponization is likely given the RCE nature.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in provided references
Vendor Advisory: Not provided in references
Restart Required: Yes
Instructions:
1. Contact Ashlar-Vellum for security updates. 2. Apply the latest patch for Cobalt. 3. Restart the application and any related services.
🔧 Temporary Workarounds
Block VC6 file extensions
allPrevent processing of potentially malicious VC6 files at the system or network level
User awareness training
allTrain users to avoid opening VC6 files from untrusted sources
🧯 If You Can't Patch
- Restrict user privileges to minimize impact of successful exploitation
- Implement application whitelisting to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check if Ashlar-Vellum Cobalt is installed and processes VC6 files. Review version against vendor patched releases.Check Version:
Check application 'About' dialog or installation directory for version informationVerify Fix Applied:
Confirm installation of latest vendor-provided patch and test with safe VC6 files to ensure proper parsing.📡 Detection & Monitoring
Log Indicators:
- Application crashes when processing VC6 files
- Unexpected memory access errors in application logs
- Unusual process creation from Cobalt executable
Network Indicators:
- Downloads of VC6 files from untrusted sources
- Unexpected outbound connections after file opening
SIEM Query:
Process creation where parent process is 'cobalt.exe' AND command line contains unusual parameters OR file access events for *.vc6 files followed by crash events