CVE-2023-34299
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code by tricking users into opening malicious CO files in Ashlar-Vellum Cobalt. Attackers can exploit a heap buffer overflow during CO file parsing to gain control of the affected process. Users of Ashlar-Vellum Cobalt who open untrusted CO files are at risk.
💻 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, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Local privilege escalation or malware execution in the context of the current user, potentially leading to data exfiltration or further system compromise.
If Mitigated
Limited impact with proper application sandboxing and user privilege restrictions, potentially resulting in application crash rather than code execution.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file) and knowledge of heap manipulation techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisory for specific patched version
Vendor Advisory: https://www.zerodayinitiative.com/advisories/ZDI-23-859/
Restart Required: Yes
Instructions:
1. Check current Cobalt version
2. Download latest update from Ashlar-Vellum
3. Install update following vendor instructions
4. Restart system if required
🔧 Temporary Workarounds
Disable CO file association
allRemove CO file type association with Cobalt to prevent automatic opening
Windows: assoc .co=
macOS: Remove CO file association in Finder preferences
Application sandboxing
allRun Cobalt with reduced privileges using application sandboxing
Windows: RunAs with limited user account
macOS: Use sandbox-exec or similar
🧯 If You Can't Patch
- Implement strict file validation policies to block untrusted CO files
- Use application whitelisting to prevent execution of malicious payloads
🔍 How to Verify
Check if Vulnerable:
Check if Cobalt version is unpatched and processes CO filesCheck Version:
Check Help > About in Cobalt applicationVerify Fix Applied:
Verify installation of latest Cobalt version from vendor📡 Detection & Monitoring
Log Indicators:
- Application crashes when processing CO files
- Unusual process spawning from Cobalt
Network Indicators:
- Outbound connections from Cobalt to unknown IPs
- Unexpected network traffic following CO file opening
SIEM Query:
Process:Name='Cobalt' AND (EventID=1000 OR ParentProcess contains 'exploit')