CVE-2021-1190
📋 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 attacker persistence, network monitoring, or lateral movement.
Likely Case
Denial of service through device reboots disrupting network connectivity for small businesses.
If Mitigated
Limited impact if strong credential management and network segmentation are implemented.
🎯 Exploit Status
Exploitation requires valid administrator credentials. Attack involves sending crafted HTTP requests to web interface.
🛠️ 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 and use alternative management methods.
Access router CLI via SSH/Telnet
Navigate to management settings
Disable HTTP/HTTPS management
Restrict Management Access
allLimit web management interface access to specific trusted IP addresses only.
Configure firewall rules on router
Set management ACLs to trusted IPs only
Disable remote management
🧯 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 if you have affected Cisco RV model and web management interface is enabled.Check Version:
Login to router web interface or CLI and check model/firmware versionVerify Fix Applied:
Verify web management interface is disabled or access restricted. No patch available to verify.📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful login
- Unusual HTTP requests to management interface
- Device reboot logs without normal cause
Network Indicators:
- Unusual outbound connections from router
- HTTP traffic to management interface from unexpected sources
SIEM Query:
source="router_logs" (event="authentication success" AND src_ip NOT IN trusted_ips) OR (event="device_reboot" AND NOT reason="scheduled")