CVE-2021-1214
📋 TL;DR
This vulnerability allows authenticated remote 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 Small Business RV110W Router
- Cisco Small Business RV130 Router
- Cisco Small Business RV130W Router
- Cisco Small Business RV215W Router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise with root-level arbitrary code execution, allowing full control of the router and potential lateral movement into connected networks.
Likely Case
Denial of service through device reboots disrupting network connectivity for connected users and services.
If Mitigated
Limited impact if strong authentication controls prevent unauthorized access to admin credentials.
🎯 Exploit Status
Exploitation requires valid administrator credentials but involves simple HTTP request crafting once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: None available
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-rv-overflow-WUnUgv4U
Restart Required: No
Instructions:
No official patch available. Cisco has not released software updates. Consider workarounds or replacement.
🔧 Temporary Workarounds
Disable Web Management Interface
allDisable the vulnerable web-based management interface to prevent exploitation
Access router CLI via SSH/Telnet
Enter configuration mode
Disable HTTP/HTTPS management service
Restrict Management Access
allLimit web management interface access to specific trusted IP addresses only
Configure firewall rules to restrict access to router management IP
Set up VPN for management access only
🧯 If You Can't Patch
- Replace affected routers with supported models that receive security updates
- Implement network segmentation to isolate vulnerable routers from critical assets
🔍 How to Verify
Check if Vulnerable:
Check router model and firmware version against affected products list. All versions of listed models are vulnerable.Check Version:
show version (via CLI) or check web interface System Information pageVerify Fix Applied:
Verify web management interface is disabled or access is properly restricted via firewall rules.📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful login
- Unusual HTTP POST requests to management interface
- Device reboot logs without scheduled maintenance
Network Indicators:
- Unusual outbound connections from router after admin login
- HTTP traffic patterns suggesting exploit attempts
SIEM Query:
source="router_logs" AND (event="authentication_success" OR event="http_request") AND (user="admin" OR uri="/cgi-bin/*")