CVE-2021-1307
📋 TL;DR
This vulnerability allows authenticated attackers with administrator credentials to execute arbitrary code as root or cause denial of service on affected Cisco Small Business routers. It affects RV110W, RV130, RV130W, and RV215W routers through improper input validation in the web management interface. Attackers can exploit it by sending crafted HTTP requests.
💻 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 full control of the router and potential lateral movement into connected networks.
Likely Case
Device reboot causing temporary denial of service, or limited code execution if attacker has admin credentials but lacks sophisticated payloads.
If Mitigated
No impact if proper network segmentation, credential protection, and access controls prevent attackers from reaching the management interface.
🎯 Exploit Status
Exploitation requires valid administrator credentials but is technically simple once credentials are obtained. No public exploit code is known.
🛠️ 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 is available from Cisco. Consider workarounds or replacement options.
🔧 Temporary Workarounds
Disable Web Management Interface
allDisable the vulnerable web-based management interface entirely
Access router CLI via SSH/Telnet
Configure no ip http server
Configure no ip http secure-server
Restrict Management Access
allLimit management interface access to specific trusted IP addresses only
Configure ip http access-class [ACL-NAME]
Create ACL permitting only trusted management stations
🧯 If You Can't Patch
- Replace affected routers with supported models that receive security updates
- Implement network segmentation to isolate routers from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Check if device model is RV110W, RV130, RV130W, or RV215W and has web management enabledCheck Version:
show versionVerify Fix Applied:
Verify web management interface is disabled or access is restricted via ACLs📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful login
- Unusual HTTP POST requests to management interface
- Device reboot logs without scheduled maintenance
Network Indicators:
- HTTP traffic to router management port from unusual sources
- Multiple authentication attempts from single source
SIEM Query:
source="router_logs" (event="authentication success" AND src_ip NOT IN trusted_management_ips) OR event="device reboot"