Overview
A critical vulnerability has been discovered in TOTOLINK EX1200T 4.1.2cu.5232_B20210713, one of the widely used network devices. This vulnerability, classified as CVE-2025-6302, poses a significant threat as it directly affects the function setStaticDhcpConfig of the file /cgi-bin/cstecgi.cgi, leading to a stack-based buffer overflow. This flaw is especially concerning, given that it can be exploited remotely, making the potential attack surface quite large. The severity of this vulnerability and its potential to cause system compromise or data leakage necessitates immediate attention and action.
Vulnerability Summary
CVE ID: CVE-2025-6302
Severity: Critical (CVSS: 8.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Remote code execution leading to potential system compromise or data leakage
Affected Products
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Product | Affected Versions
TOTOLINK EX1200T | 4.1.2cu.5232_B20210713
How the Exploit Works
The vulnerability exists due to insufficient input validation of the ‘Comment’ argument in the setStaticDhcpConfig function in the /cgi-bin/cstecgi.cgi file. An attacker can exploit this flaw by sending a specially crafted request containing an overly long ‘Comment’ value. This can lead to a buffer overflow condition where arbitrary code can be executed in the context of the application, leading to system compromise or data leakage.
Conceptual Example Code
Here is a conceptual example of how the vulnerability might be exploited using a HTTP request:
POST /cgi-bin/cstecgi.cgi HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
function=setStaticDhcpConfig&Comment=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA...[long string of 'A's]...This HTTP request would send a specially crafted ‘Comment’ argument that could overflow the buffer and potentially allow the execution of arbitrary code.
Mitigation Guidance
To mitigate this vulnerability, users are recommended to apply the vendor patch as soon as it’s available. In the meantime, users can deploy a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) as a temporary solution. These systems can help detect and block attempts to exploit this vulnerability, thereby providing some degree of protection until a permanent fix is applied.