CVE-2021-1206
📋 TL;DR
This vulnerability allows authenticated attackers to execute arbitrary code as root or cause denial of service on affected Cisco Small Business routers. Attackers need valid administrator credentials to exploit these input validation flaws in the web management interface. Organizations using Cisco RV110W, RV130, RV130W, or RV215W routers are affected.
💻 Affected Systems
- Cisco RV110W
- Cisco RV130
- Cisco RV130W
- Cisco RV215W
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise with root-level code execution, allowing attacker persistence, data theft, and use as pivot point in network.
Likely Case
Device reboot causing temporary service disruption, or limited code execution if attacker has admin access but limited network position.
If Mitigated
No impact if proper credential management and network segmentation prevent attacker access to admin interface.
🎯 Exploit Status
Exploitation requires authenticated access but is straightforward once credentials are obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: None - devices are end-of-life
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-rv-overflow-WUnUgv4U
Restart Required: No
Instructions:
No official patch available. Cisco recommends replacing affected devices with supported models.
🔧 Temporary Workarounds
Disable web management interface
allDisable the vulnerable web interface and use alternative management methods
Access router CLI via SSH/Telnet and disable web interface through configuration
Restrict management access
allLimit web interface access to specific trusted IP addresses only
Configure firewall rules to restrict access to router management IP/ports
🧯 If You Can't Patch
- Replace affected routers with supported models immediately
- Implement strict network segmentation to isolate routers from critical assets
🔍 How to Verify
Check if Vulnerable:
Check router model and firmware version via web interface or CLI 'show version' commandCheck Version:
show versionVerify Fix Applied:
Verify router has been replaced with supported model or web interface is disabled📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful login and unusual HTTP requests
- Device reboot logs without scheduled maintenance
Network Indicators:
- Unusual outbound connections from router
- HTTP requests with malformed parameters to management interface
SIEM Query:
source="router_logs" (event="authentication_success" AND user="admin") FOLLOWED BY event="http_request" WITHIN 5m