CVE-2025-25635
📋 TL;DR
This CVE describes a buffer overflow vulnerability in TOTOlink A3002R routers, caused by improper input validation of the pppoe_dns1 parameter in the formIpv6Setup interface. It allows attackers to potentially execute arbitrary code or crash the device, affecting users of the specified router model and firmware version.
💻 Affected Systems
- TOTOlink A3002R
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to full device compromise, enabling attackers to steal data, deploy malware, or pivot to other network systems.
Likely Case
Denial-of-service by crashing the router, disrupting network connectivity for users.
If Mitigated
Limited impact if the device is isolated from untrusted networks or patched, with no data breach or persistent access.
🎯 Exploit Status
Exploitation requires sending crafted requests to the vulnerable interface; no public proof-of-concept is available, but details are documented in references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor for updated firmware beyond V1.1.1-B20200824.0128
Vendor Advisory: Not provided in input; monitor TOTOlink's official website or security advisories.
Restart Required: No
Instructions:
1. Visit TOTOlink's support page. 2. Download the latest firmware for A3002R. 3. Log into the router's admin interface. 4. Navigate to firmware update section. 5. Upload and apply the new firmware file.
🔧 Temporary Workarounds
Disable IPv6 Setup Interface
allPrevent access to the vulnerable formIpv6Setup interface by disabling IPv6 configuration if not needed.
Log into router admin, navigate to network settings, disable IPv6 or restrict access to the interface.
🧯 If You Can't Patch
- Isolate the router on a separate VLAN to limit attack surface and contain potential breaches.
- Implement network segmentation and firewall rules to block external access to the router's web management interface.
🔍 How to Verify
Check if Vulnerable:
Check the router's firmware version via the admin interface; if it matches V1.1.1-B20200824.0128, it is vulnerable.Check Version:
Log into the router's web interface and navigate to System Info or similar section to view firmware version.Verify Fix Applied:
After updating, verify the firmware version has changed to a newer release not listed as affected.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to /bin/boa with long pppoe_dns1 parameters, or system crash logs indicating buffer overflow.
Network Indicators:
- Suspicious traffic patterns targeting the router's IP on port 80 or 443 with crafted payloads.
SIEM Query:
source="router_logs" AND (uri="/bin/boa" AND method="POST" AND param="pppoe_dns1" AND length(param) > 100)