CVE-2021-1210
📋 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 RV110W
- Cisco RV130
- Cisco RV130W
- Cisco RV215W
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise with root-level arbitrary code execution, allowing attackers to install persistent malware, steal credentials, pivot to internal networks, or permanently disable the device.
Likely Case
Device reboot causing temporary network outage, or limited code execution to modify configurations, intercept traffic, or establish foothold for lateral movement.
If Mitigated
No impact if proper credential management and network segmentation prevent attackers from reaching the management interface with admin credentials.
🎯 Exploit Status
Exploitation requires admin credentials but involves simple HTTP request crafting. No public exploit code identified.
🛠️ 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:
Cisco has not released software updates. Consider replacing affected devices with supported models.
🔧 Temporary Workarounds
Disable web management interface
allDisable the vulnerable web-based management interface and use alternative management methods
Restrict management access
allLimit management interface access to specific trusted IP addresses using ACLs
🧯 If You Can't Patch
- Replace affected routers with supported models that receive security updates
- Implement network segmentation to isolate routers from critical assets
🔍 How to Verify
Check if Vulnerable:
Check device model via web interface or CLI: show version. If model is RV110W, RV130, RV130W, or RV215W, device is vulnerable.Check Version:
show versionVerify Fix Applied:
No fix available to verify. Verify workarounds by confirming web interface is disabled or access is restricted.📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful login and unusual HTTP requests to management interface
- Device reboot logs without authorized maintenance
Network Indicators:
- Unusual outbound connections from router to external IPs
- HTTP requests with crafted parameters to router management interface
SIEM Query:
source="router_logs" AND (event="authentication_success" AND src_ip NOT IN trusted_networks) OR (event="device_reboot" AND NOT maintenance_window)