CVE-2021-1344
📋 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 with valid administrator credentials can exploit improper input validation in the web management interface via crafted HTTP requests. Organizations using Cisco RV016, RV042, RV042G, RV082, RV320, or RV325 routers are affected.
💻 Affected Systems
- Cisco RV016
- Cisco RV042
- Cisco RV042G
- Cisco RV082
- Cisco RV320
- Cisco RV325
📦 What is this software?
Rv016 Multi Wan Vpn Router Firmware by Cisco
View all CVEs affecting Rv016 Multi Wan Vpn Router Firmware →
Rv042 Dual Wan Vpn Router Firmware by Cisco
View all CVEs affecting Rv042 Dual Wan Vpn Router Firmware →
Rv042g Dual Gigabit Wan Vpn Router Firmware by Cisco
View all CVEs affecting Rv042g Dual Gigabit Wan Vpn Router Firmware →
Rv082 Dual Wan Vpn Router Firmware by Cisco
View all CVEs affecting Rv082 Dual Wan Vpn Router Firmware →
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise with root-level arbitrary code execution, allowing attackers to steal data, pivot to internal networks, or permanently disable the device.
Likely Case
Authenticated attackers gaining full control of affected routers, potentially leading to network disruption, data interception, or persistent backdoor installation.
If Mitigated
Limited impact if strong authentication controls prevent unauthorized access to admin credentials and network segmentation isolates the management interface.
🎯 Exploit Status
Exploitation requires valid admin credentials but is straightforward once credentials are obtained. No public exploit code is confirmed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Cisco advisory for specific fixed versions per model
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-rv-overflow-ghZP68yj
Restart Required: Yes
Instructions:
1. Access router web interface. 2. Navigate to Administration > Firmware Upgrade. 3. Download latest firmware from Cisco. 4. Upload and install firmware. 5. Reboot router after installation.
🔧 Temporary Workarounds
Disable web management interface
allDisable the vulnerable web interface and use alternative management methods
Access router CLI via SSH/Telnet
Configure via console cable
Restrict management access
allLimit web interface access to specific trusted IP addresses only
Configure firewall rules to restrict management port access
🧯 If You Can't Patch
- Implement strict access controls and network segmentation for management interfaces
- Enforce strong, unique administrator credentials and enable multi-factor authentication if available
🔍 How to Verify
Check if Vulnerable:
Check router firmware version against Cisco advisory. Access web interface > Status > Router to view current version.Check Version:
Show version via CLI or check web interface Status > Router pageVerify Fix Applied:
Verify firmware version matches or exceeds fixed versions listed in Cisco advisory after patching.📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful login
- Unusual HTTP requests to management interface
- Router reboot events without scheduled maintenance
Network Indicators:
- Unusual outbound connections from router
- HTTP traffic patterns matching exploit attempts
SIEM Query:
source="router_logs" AND (event="authentication_success" AND user="admin" FROM unusual_ip) OR (event="http_request" AND uri CONTAINS "/admin/")