CVE-2021-1163
📋 TL;DR
Multiple buffer overflow vulnerabilities in Cisco Small Business RV series routers allow authenticated remote 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
Full device compromise with root-level arbitrary code execution, allowing complete control of the router and potential lateral movement into connected networks.
Likely Case
Denial of service through device reboots, disrupting network connectivity for connected users and services.
If Mitigated
Limited impact if strong credential management and network segmentation are implemented, though risk remains from credential theft.
🎯 Exploit Status
Requires valid administrator credentials. Exploitation involves sending crafted HTTP requests to the web interface.
🛠️ 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 available. Cisco has not released software updates. Consider workarounds or replacement.
🔧 Temporary Workarounds
Disable web-based management interface
allDisable the vulnerable web interface and use alternative management methods like CLI or serial console
Restrict management access
allLimit web interface access to specific trusted IP addresses using firewall rules
🧯 If You Can't Patch
- Replace affected devices 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 device model and firmware version via web interface or CLI. If model is RV110W, RV130, RV130W, or RV215W, device 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
- Unusual HTTP POST requests to management interface
- Device reboot logs without scheduled maintenance
Network Indicators:
- HTTP traffic to router management interface from unexpected sources
- Multiple connection attempts to router web interface
SIEM Query:
source="router_logs" AND (event_type="authentication" AND result="success") AND src_ip NOT IN [trusted_management_ips]