CVE-2021-1216
📋 TL;DR
Multiple input validation vulnerabilities in Cisco Small Business routers allow authenticated attackers to execute arbitrary code as root or cause denial of service. Attackers need valid administrator credentials to exploit these vulnerabilities. Affected devices include RV110W, RV130, RV130W, and RV215W routers.
💻 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
Denial of service through device reboot or limited code execution for persistence and credential harvesting.
If Mitigated
No impact if proper credential management and network segmentation are implemented.
🎯 Exploit Status
Exploitation requires valid admin credentials but is straightforward 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. 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
Restrict management access
allLimit web management interface access to specific trusted IP addresses only
🧯 If You Can't Patch
- Replace affected routers with supported models that receive security updates
- Implement strict network segmentation to isolate vulnerable routers from critical assets
🔍 How to Verify
Check if Vulnerable:
Check router model and firmware version via web interface or CLI. If model is RV110W, RV130, RV130W, or RV215W, it is vulnerable.Check Version:
Login to web interface and check System Summary or use CLI command 'show version'Verify Fix Applied:
No fix available to verify. Verify workarounds by confirming web interface is disabled or access is restricted.📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful login and unusual HTTP requests
- Device reboot logs without scheduled maintenance
Network Indicators:
- Unusual HTTP traffic patterns to router management interface
- Outbound connections from router to unexpected destinations
SIEM Query:
source="router_logs" AND (event="authentication_success" AND user="admin" AND src_ip NOT IN [trusted_ips]) OR event="device_reboot"