CVE-2023-20091
📋 TL;DR
This vulnerability allows authenticated local attackers with remote support accounts to overwrite arbitrary files on Cisco TelePresence CE and RoomOS devices via symbolic link attacks due to improper file access controls. It affects Cisco TelePresence CE and RoomOS software. Attackers need local access and specific credentials to exploit this flaw.
💻 Affected Systems
- Cisco TelePresence CE
- Cisco RoomOS
📦 What is this software?
Roomos by Cisco
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through overwriting critical system files, potentially leading to persistent backdoors, service disruption, or credential theft.
Likely Case
Limited file manipulation by authorized users abusing their privileges to modify configuration files or logs.
If Mitigated
No impact if proper access controls and patching are implemented, restricting file write permissions.
🎯 Exploit Status
Requires authenticated local access with remote support privileges and knowledge of specific file system locations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Cisco advisory for specific patched versions
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-roomos-file-write-rHKwegKf
Restart Required: Yes
Instructions:
1. Review Cisco advisory for affected versions. 2. Download and apply the latest software update from Cisco. 3. Restart the device to apply changes. 4. Verify the update was successful.
🧯 If You Can't Patch
- Remove or restrict remote support user accounts to minimize attack surface.
- Implement strict file system permissions and monitoring for unauthorized file modifications.
🔍 How to Verify
Check if Vulnerable:
Check device software version against Cisco advisory; devices with vulnerable versions are affected.Check Version:
Check device web interface or CLI for software version information (specific command varies by device).Verify Fix Applied:
Verify software version is updated to patched version listed in Cisco advisory.📡 Detection & Monitoring
Log Indicators:
- Unusual file modification events in system logs
- Symbolic link creation in specific directories
- Remote support account activity leading to file writes
Network Indicators:
- No direct network indicators as exploit is local
SIEM Query:
Search for file modification events from remote support user accounts or symbolic link creation in system directories.