CVE-2021-34979
📋 TL;DR
CVE-2021-34979 is a buffer overflow vulnerability in NETGEAR R6260 routers that allows network-adjacent attackers to execute arbitrary code as root without authentication. The flaw exists in SOAP request handling where improper length validation enables remote code execution. This affects NETGEAR R6260 routers running vulnerable firmware versions.
💻 Affected Systems
- NETGEAR R6260
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router with root-level code execution, allowing attackers to intercept traffic, modify configurations, install persistent malware, and pivot to internal networks.
Likely Case
Router takeover enabling traffic interception, DNS manipulation, credential theft, and network reconnaissance from a privileged position.
If Mitigated
Limited impact if router is isolated from internal networks and regularly monitored for unauthorized configuration changes.
🎯 Exploit Status
Exploit requires network adjacency but no authentication. Public exploit code exists in security advisories and research publications.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.1.0.80_1.0.1 and later
Vendor Advisory: https://kb.netgear.com/000064261/Security-Advisory-for-Vertical-Privilege-Escalation-on-Some-Routers-PSV-2021-0152
Restart Required: Yes
Instructions:
1. Log into router admin interface. 2. Navigate to Advanced > Administration > Firmware Update. 3. Check for updates and install firmware version 1.1.0.80_1.0.1 or later. 4. Reboot router after update completes.
🔧 Temporary Workarounds
Disable SOAP service
allDisable the vulnerable SOAP service if not required for functionality
Network segmentation
allIsolate router management interface from untrusted networks
🧯 If You Can't Patch
- Replace vulnerable router with updated model or different vendor
- Implement strict network segmentation to limit router exposure
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under Advanced > Administration > Firmware UpdateCheck Version:
Not applicable - check via web interfaceVerify Fix Applied:
Verify firmware version is 1.1.0.80_1.0.1 or later in router admin interface📡 Detection & Monitoring
Log Indicators:
- Unusual SOAP requests to router management interface
- Multiple failed buffer overflow attempts in system logs
- Unexpected process execution or configuration changes
Network Indicators:
- Unusual SOAP traffic to router on management ports
- Traffic patterns suggesting router compromise
SIEM Query:
source="router_logs" AND ("SOAPAction" OR "buffer overflow" OR "privilege escalation")🔗 References
- https://kb.netgear.com/000064261/Security-Advisory-for-Vertical-Privilege-Escalation-on-Some-Routers-PSV-2021-0152?article=000064261
- https://www.zerodayinitiative.com/advisories/ZDI-21-1241/
- https://kb.netgear.com/000064261/Security-Advisory-for-Vertical-Privilege-Escalation-on-Some-Routers-PSV-2021-0152?article=000064261
- https://www.zerodayinitiative.com/advisories/ZDI-21-1241/
