CVE-2025-6163 Overview
CVE-2025-6163 is a buffer overflow vulnerability in the TOTOLINK A3002RU router running firmware version 3.0.0-B20230809.1615. The flaw resides in the HTTP POST request handler for the /boafrm/formMultiAP endpoint. Attackers can exploit the submit-url argument to trigger a memory corruption condition over the network. The exploit has been publicly disclosed, increasing the likelihood of opportunistic attacks against exposed devices. The vulnerability is tracked under CWE-119, covering improper restriction of operations within the bounds of a memory buffer.
Critical Impact
Remote attackers with low-privilege access can corrupt router memory through a crafted HTTP POST request, potentially achieving code execution or device disruption.
Affected Products
- TOTOLINK A3002RU hardware device
- TOTOLINK A3002RU firmware version 3.0.0-B20230809.1615
- Deployments exposing the device web management interface to untrusted networks
Discovery Timeline
- 2025-06-17 - CVE-2025-6163 published to NVD
- 2025-06-23 - Last updated in NVD database
Technical Details for CVE-2025-6163
Vulnerability Analysis
The vulnerability exists in the HTTP POST request handler bound to the /boafrm/formMultiAP URI on the TOTOLINK A3002RU web administration interface. The handler processes the submit-url parameter without enforcing length validation on the supplied input. A sufficiently long value overflows a fixed-size buffer in the handling routine, corrupting adjacent stack or heap memory. The condition aligns with [CWE-119], improper restriction of operations within memory buffer bounds.
Attackers reach the vulnerable code path over the network after authenticating with low-privilege credentials. Successful exploitation can corrupt control flow data, enabling denial of service or arbitrary code execution on the embedded device. According to EPSS data, the probability of exploitation activity sits at 0.761%.
Root Cause
The formMultiAP handler copies the attacker-controlled submit-url value into a fixed-length buffer using an unsafe string operation. The function lacks bounds checking on the parameter length before the copy operation. TOTOLINK firmware for the A3002RU model frequently uses the boa web server with custom CGI form handlers, and similar patterns have produced overflow conditions across the vendor's product line.
Attack Vector
Exploitation requires network access to the device management interface and a valid low-privilege session. The attacker submits a crafted HTTP POST request to /boafrm/formMultiAP with an oversized submit-url field. The vulnerable handler copies the payload into a constrained buffer, overwriting adjacent memory and altering execution state.
The vulnerability mechanism is described in the GitHub PoC Repository and tracked in VulDB #312638. No verified exploit code is reproduced here; refer to the public references for technical artifacts.
Detection Methods for CVE-2025-6163
Indicators of Compromise
- HTTP POST requests to /boafrm/formMultiAP containing unusually long submit-url parameter values
- Unexpected reboots, crashes, or service restarts on TOTOLINK A3002RU devices following web interface activity
- Authentication events from unfamiliar source addresses immediately preceding malformed POST traffic
Detection Strategies
- Inspect network traffic for POST requests targeting /boafrm/formMultiAP with submit-url values exceeding expected length thresholds
- Deploy intrusion detection signatures matching oversized form field submissions to TOTOLINK boafrm handlers
- Correlate device crash logs with preceding HTTP administrative traffic to identify exploitation attempts
Monitoring Recommendations
- Log all administrative HTTP traffic to TOTOLINK devices and forward to a centralized analytics platform
- Alert on repeated authentication failures or session creation immediately before large POST payloads
- Monitor router uptime and configuration drift for signs of post-exploitation persistence
How to Mitigate CVE-2025-6163
Immediate Actions Required
- Restrict access to the TOTOLINK A3002RU web administration interface to trusted management networks only
- Disable remote (WAN-side) management on affected devices until a vendor patch is available
- Rotate administrative credentials and enforce strong passwords to limit low-privilege account abuse
- Inventory deployed TOTOLINK A3002RU units running firmware 3.0.0-B20230809.1615 and prioritize segmentation
Patch Information
At the time of NVD publication, no vendor-supplied patch is referenced in the advisory. Monitor the Totolink Security Page for firmware updates addressing the formMultiAP handler. Apply replacement firmware promptly once released and verify the fixed build no longer accepts oversized submit-url values.
Workarounds
- Place affected devices behind a network firewall that blocks inbound connections to the management port
- Use access control lists to restrict the device HTTP interface to specific administrator workstations
- Consider replacing end-of-support TOTOLINK A3002RU units with actively maintained networking equipment if no patch is forthcoming
# Example firewall rule restricting management access to a trusted subnet
iptables -A INPUT -p tcp --dport 80 -s 192.0.2.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
