CVE-2021-1314
📋 TL;DR
This vulnerability allows authenticated remote attackers with administrator credentials to execute arbitrary commands with root privileges on affected Cisco Small Business routers. The vulnerability exists in the web-based management interface due to improper input validation. Attackers can exploit this by sending crafted HTTP requests to gain full control of the device.
💻 Affected Systems
- Cisco Small Business RV016
- RV042
- RV042G
- RV082
- RV320
- 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 compromise of the router allowing attackers to intercept all network traffic, install persistent backdoors, pivot to internal networks, and use the device for further attacks.
Likely Case
Attackers with stolen or default admin credentials gain full control of the router to monitor traffic, modify configurations, or use as a foothold for internal network attacks.
If Mitigated
With strong authentication and network segmentation, impact is limited to the router itself, though complete compromise still allows traffic interception.
🎯 Exploit Status
Exploitation requires valid admin credentials. Public exploit code exists for similar Cisco router vulnerabilities.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: RV016: 4.2.3.14, RV042/RV042G: 4.2.3.14, RV082: 4.2.3.14, RV320/RV325: 1.5.1.11
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-rv-command-inject-BY4c5zd
Restart Required: Yes
Instructions:
1. Log into router web interface. 2. Navigate to Administration > Firmware Upgrade. 3. Download appropriate firmware from Cisco support site. 4. Upload and install firmware. 5. Router will reboot automatically.
🔧 Temporary Workarounds
Disable web management interface
allDisable the vulnerable web interface and use alternative management methods
Navigate to Administration > Management > HTTP/HTTPS Service and disable
Restrict management access
allLimit web interface access to specific trusted IP addresses only
Navigate to Firewall > Access Rules to restrict management interface access
🧯 If You Can't Patch
- Change all default admin credentials to strong, unique passwords
- Disable remote management and only allow local network access to management interface
🔍 How to Verify
Check if Vulnerable:
Check firmware version in web interface: Status > Router > Firmware VersionCheck Version:
Check via web interface or SSH: show versionVerify Fix Applied:
Verify firmware version matches or exceeds patched versions listed in advisory📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to management interface
- Multiple failed login attempts followed by successful login
- Commands containing shell metacharacters in HTTP parameters
Network Indicators:
- HTTP requests with command injection payloads to router management port
- Unusual outbound connections from router to external IPs
SIEM Query:
source="router_logs" AND (http_method="POST" AND (uri="/login.cgi" OR uri="/apply.cgi") AND (param="*;*" OR param="*|*" OR param="*`*"))