CVE-2025-60685
📋 TL;DR
A stack buffer overflow vulnerability in ToToLink A720R router firmware allows attackers with filesystem write access to execute arbitrary code by crafting malicious /proc/stat content. This affects users of ToToLink A720R routers running vulnerable firmware versions. Attackers could potentially gain full control of affected routers.
💻 Affected Systems
- ToToLink A720R Router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete router compromise, credential theft, network traffic interception, and lateral movement into connected networks.
Likely Case
Local privilege escalation from a low-privileged user to root access on the router, enabling persistence and configuration changes.
If Mitigated
Limited impact if filesystem write access is properly restricted and routers are not exposed to untrusted users.
🎯 Exploit Status
Exploit requires filesystem write access to craft malicious /proc/stat content. Public PoC available on GitHub.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: Yes
Instructions:
1. Check ToToLink website for firmware updates
2. Download latest firmware for A720R
3. Upload via router admin interface
4. Reboot router after update
🔧 Temporary Workarounds
Restrict filesystem access
linuxLimit filesystem write permissions to prevent malicious /proc/stat modification
chmod 644 /proc/stat
chown root:root /proc/stat
Disable unnecessary services
allReduce attack surface by disabling unused router services
🧯 If You Can't Patch
- Isolate affected routers in separate network segments
- Implement strict access controls and monitor for suspicious filesystem activity
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via admin interface or SSH: cat /proc/version | grep -i totolinkCheck Version:
cat /proc/version | grep -i totolink || cat /etc/versionVerify Fix Applied:
Verify firmware version is newer than V4.1.5cu.614_B20230630📡 Detection & Monitoring
Log Indicators:
- Unusual /proc/stat modifications
- sysconf binary crashes
- Unexpected process execution
Network Indicators:
- Unusual outbound connections from router
- DNS changes
- Port forwarding modifications
SIEM Query:
process:sysconf AND (event:crash OR event:privilege_escalation)