CVE-2021-1293
📋 TL;DR
This critical vulnerability allows unauthenticated remote attackers to execute arbitrary code as root on affected Cisco Small Business VPN routers. Attackers can exploit it by sending specially crafted HTTP requests to the web management interface. Organizations using Cisco RV160, RV160W, RV260, RV260P, or RV260W VPN routers are affected.
💻 Affected Systems
- Cisco Small Business RV160 VPN Router
- Cisco Small Business RV160W VPN Router
- Cisco Small Business RV260 VPN Router
- Cisco Small Business RV260P VPN Router
- Cisco Small Business RV260W VPN Router
📦 What is this software?
Rv160w Wireless Ac Vpn Router Firmware by Cisco
View all CVEs affecting Rv160w Wireless Ac Vpn Router Firmware →
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of affected routers allowing attackers to establish persistent access, intercept network traffic, pivot to internal networks, and potentially disable network connectivity.
Likely Case
Attackers gain root access to routers, enabling them to reconfigure devices, steal credentials, monitor network traffic, and use routers as footholds for further attacks.
If Mitigated
With proper network segmentation and access controls, impact is limited to the router itself rather than allowing lateral movement to internal systems.
🎯 Exploit Status
Exploitation requires no authentication and has been publicly demonstrated. The vulnerability is in HTTP request handling, making exploitation straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.0.01.02 or later
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-rv160-260-rce-XZeFkNHf
Restart Required: Yes
Instructions:
1. Log into router web interface. 2. Navigate to Administration > Firmware Upgrade. 3. Download firmware version 1.0.01.02 or later from Cisco website. 4. Upload and install the firmware. 5. Reboot the router after installation completes.
🔧 Temporary Workarounds
Restrict Management Interface Access
allLimit access to the web management interface to trusted IP addresses only
Configure firewall rules to restrict access to router management IP/port (typically TCP 443/80) to authorized management networks only
Disable Remote Management
allDisable web management interface from WAN/external interfaces
In router web interface: Administration > Management > Remote Management > Disable
🧯 If You Can't Patch
- Immediately restrict web management interface access to trusted internal IP addresses only
- Implement network monitoring for suspicious HTTP requests to router management interfaces
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface: System Summary > Firmware Version. If version is earlier than 1.0.01.02, device is vulnerable.Check Version:
Check via web interface or SSH: show version (if SSH enabled)Verify Fix Applied:
After patching, verify firmware version shows 1.0.01.02 or later in System Summary > Firmware Version.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to management interface
- Multiple failed login attempts followed by successful access
- Configuration changes from unexpected sources
Network Indicators:
- HTTP requests with unusual headers or parameters to router management ports
- Outbound connections from router to suspicious external IPs
SIEM Query:
source_ip="router_management_ip" AND (http_method="POST" OR http_method="GET") AND (http_uri contains "/admin/" OR http_uri contains "/cgi-bin/") AND http_user_agent="unusual_value"