CVE-2021-41193
📋 TL;DR
CVE-2021-41193 is a remote format string vulnerability in wire-avs, the audio visual signaling component of Wire messenger. This allows attackers to cause denial of service or potentially execute arbitrary code by sending specially crafted input. All Wire installations using wire-avs versions before 7.1.12 are affected.
💻 Affected Systems
- Wire messenger
- wire-avs component
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with full system compromise, allowing attackers to take control of affected systems.
Likely Case
Denial of service causing Wire's audio/video functionality to crash, disrupting communication services.
If Mitigated
Limited impact if proper network segmentation and access controls prevent external attackers from reaching vulnerable components.
🎯 Exploit Status
Format string vulnerabilities typically require some understanding of memory layout and exploitation techniques, but the remote nature makes this serious.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: wire-avs 7.1.12
Vendor Advisory: https://github.com/wireapp/wire-avs/security/advisories/GHSA-2j6v-xpf3-xvrv
Restart Required: Yes
Instructions:
1. Update wire-avs to version 7.1.12 or later. 2. Update Wire messenger to latest version. 3. Restart Wire services. 4. Verify the update was successful.
🔧 Temporary Workarounds
No official workarounds
allThe vendor states there are no known workarounds for this vulnerability.
🧯 If You Can't Patch
- Isolate Wire servers behind firewalls with strict access controls
- Disable audio/video functionality if not required
🔍 How to Verify
Check if Vulnerable:
Check wire-avs version: If version is less than 7.1.12, system is vulnerable.Check Version:
Check Wire application version or examine wire-avs package version in package manager.Verify Fix Applied:
Verify wire-avs version is 7.1.12 or higher after update.📡 Detection & Monitoring
Log Indicators:
- Crash logs from wire-avs process
- Unusual format string patterns in audio/video session logs
Network Indicators:
- Unusual traffic patterns to Wire audio/video ports
- Malformed protocol packets
SIEM Query:
Process:wire-avs AND (EventType:Crash OR ErrorCode:*format*)🔗 References
- https://github.com/wireapp/wire-avs/commit/40d373ede795443ae6f2f756e9fb1f4f4ae90bbe
- https://github.com/wireapp/wire-avs/security/advisories/GHSA-2j6v-xpf3-xvrv
- https://github.com/wireapp/wire-avs/commit/40d373ede795443ae6f2f756e9fb1f4f4ae90bbe
- https://github.com/wireapp/wire-avs/security/advisories/GHSA-2j6v-xpf3-xvrv
