CVE-2020-3603
📋 TL;DR
This vulnerability allows remote code execution through malicious Webex recording files (ARF/WRF format). Attackers can exploit it by tricking users into opening specially crafted files, potentially gaining control of affected Windows systems running vulnerable Webex players.
💻 Affected Systems
- Cisco Webex Network Recording Player
- Cisco Webex Player
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining the same privileges as the user who opens the malicious file, potentially leading to data theft, ransomware deployment, or lateral movement.
Likely Case
Malware installation or credential theft through spear-phishing campaigns targeting users who regularly handle Webex recordings.
If Mitigated
Limited impact if users have restricted privileges, email filtering blocks malicious attachments, and security awareness prevents opening suspicious files.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file). The vulnerability is in file parsing logic, making reliable exploitation likely.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Webex Network Recording Player 40.1.2 or later, Webex Player 40.1.0 or later
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-nbr-NOS6FQ24
Restart Required: Yes
Instructions:
1. Download latest version from Cisco Webex Downloads site. 2. Run installer with administrative privileges. 3. Restart system after installation completes.
🔧 Temporary Workarounds
Disable file association
windowsRemove ARF and WRF file associations with vulnerable Webex players
Open Control Panel > Default Programs > Set Associations, remove .arf and .wrf associations with Webex players
Application control policy
windowsBlock execution of vulnerable Webex player versions
🧯 If You Can't Patch
- Implement strict email filtering to block ARF/WRF attachments
- Train users to never open Webex recordings from untrusted sources
🔍 How to Verify
Check if Vulnerable:
Check Webex player version via Help > About menu. If version is earlier than 40.1.2 for Network Recording Player or 40.1.0 for Webex Player, system is vulnerable.Check Version:
wmic product where name like "%Webex%" get versionVerify Fix Applied:
Confirm version is 40.1.2 or later for Network Recording Player, or 40.1.0 or later for Webex Player via Help > About menu.📡 Detection & Monitoring
Log Indicators:
- Process creation events for Webex players opening ARF/WRF files
- Application crash logs from Webex players
Network Indicators:
- Email attachments with .arf or .wrf extensions
- Downloads of Webex recording files from untrusted sources
SIEM Query:
source="windows" AND (process_name="*Webex*" AND file_extension IN (".arf", ".wrf"))🔗 References
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-nbr-NOS6FQ24
- https://www.zerodayinitiative.com/advisories/ZDI-20-1361/
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-nbr-NOS6FQ24
- https://www.zerodayinitiative.com/advisories/ZDI-20-1361/
