CVE-2021-1459
📋 TL;DR
This critical vulnerability allows unauthenticated remote attackers to execute arbitrary code as root on affected Cisco Small Business routers via crafted HTTP requests to the web management interface. It affects RV110W, RV130, RV130W, and RV215W routers with no available patches from Cisco. The vulnerability stems from improper input validation in the web interface.
💻 Affected Systems
- Cisco RV110W
- Cisco RV130
- Cisco RV130W
- Cisco RV215W
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attacker to install persistent backdoors, intercept all network traffic, pivot to internal networks, or render device inoperable.
Likely Case
Remote code execution leading to botnet enrollment, credential theft, network reconnaissance, or denial of service.
If Mitigated
Limited impact if web interface is disabled or inaccessible, though other attack vectors may still exist.
🎯 Exploit Status
Exploitation requires sending crafted HTTP requests to the web interface. Multiple public proof-of-concept exploits exist.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: None available
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-rv-rce-q3rxHnvm
Restart Required: No
Instructions:
No official patch available. Cisco recommends replacing affected devices with supported models.
🔧 Temporary Workarounds
Disable Web Management Interface
allCompletely disable the vulnerable web interface to prevent exploitation
Access router CLI via SSH/Telnet
Configure no ip http server
Configure no ip http secure-server
Restrict Web Interface Access
allLimit web interface access to trusted IP addresses only
Configure ip http access-class [ACL_NAME]
Create ACL permitting only trusted management IPs
🧯 If You Can't Patch
- Immediately replace affected routers with supported models
- Segment affected devices in isolated network zones with strict firewall rules
🔍 How to Verify
Check if Vulnerable:
Check router model and firmware version via web interface or CLI 'show version' commandCheck Version:
show versionVerify Fix Applied:
Verify web interface is disabled or access-restricted, test HTTP/HTTPS connectivity to management ports📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to management interface
- Multiple failed login attempts followed by successful access
- Unexpected configuration changes
Network Indicators:
- HTTP/HTTPS traffic to router management ports from unexpected sources
- Outbound connections from router to suspicious IPs
SIEM Query:
source_ip=router_management_ip AND (http_method=POST OR http_uri CONTAINS '/login.cgi') AND http_status=200