CVE-2021-31513
📋 TL;DR
CVE-2021-31513 is a buffer overflow vulnerability in OpenText Brava! Desktop's BMP file parser that allows remote code execution. Attackers can exploit this by tricking users into opening malicious BMP files or visiting malicious web pages. This affects users of OpenText Brava! Desktop version 16.6.4.55.
💻 Affected Systems
- OpenText Brava! Desktop
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control of the affected system, data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Malware installation, data exfiltration, or system disruption through crafted BMP files delivered via phishing or malicious websites.
If Mitigated
Limited impact with proper application sandboxing, user privilege restrictions, and network segmentation preventing lateral movement.
🎯 Exploit Status
Exploitation requires user interaction but is technically straightforward once a malicious file is opened.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 16.6.4.55
Vendor Advisory: https://www.opentext.com/products/brava
Restart Required: Yes
Instructions:
1. Download the latest version from OpenText's official website. 2. Run the installer to upgrade. 3. Restart the system to complete the installation.
🔧 Temporary Workarounds
Disable BMP file association
windowsRemove Brava! Desktop as the default handler for BMP files to prevent automatic exploitation
Control Panel > Default Programs > Set Default Programs > Select Brava > Choose defaults for this program > Uncheck .bmp
Application control policy
windowsBlock execution of Brava! Desktop via application whitelisting
🧯 If You Can't Patch
- Implement strict email filtering to block BMP attachments
- Deploy endpoint protection with memory protection capabilities
🔍 How to Verify
Check if Vulnerable:
Check Help > About in Brava! Desktop to see if version is 16.6.4.55Check Version:
Not applicable - check via GUI in Help > AboutVerify Fix Applied:
Verify version is higher than 16.6.4.55 in Help > About📡 Detection & Monitoring
Log Indicators:
- Process creation events for Brava! Desktop with suspicious parent processes
- Crash reports from Brava! Desktop
Network Indicators:
- Unexpected outbound connections from Brava! Desktop process
SIEM Query:
ProcessName="BravaDesktop.exe" AND (ParentImage="*powershell*" OR ParentImage="*cmd*" OR ParentImage="*rundll32*")🔗 References
- https://www.zerodayinitiative.com/advisories/ZDI-21-691/
- https://www.cvedetails.com/vulnerability-list/vendor_id-2032/product_id-96672/Opentext-Brava-Desktop.html?page=1&opec=1&order=1&trc=35&sha=37f4ed0596f8ccacca7d571f22a38c97b0f19f4c
- https://www.opentext.com/products/brava
- https://www.zerodayinitiative.com/advisories/ZDI-21-691/
