Overview
The cybersecurity landscape is constantly evolving, and a new critical vulnerability, CVE-2025-5794, has emerged, threatening the security of devices using Tenda AC5 15.03.06.47. This vulnerability pertains to a buffer overflow in the function formSetPPTPUserList, found in the file /goform/setPptpUserList. The implications of this vulnerability are serious, given that it can be exploited remotely, potentially leading to system compromise or data leakage.
This blog post aims to shed light on the specifics of this vulnerability, its impact, and the steps necessary for mitigation. As buffer overflow vulnerabilities are a common attack vector, understanding the nature of this exploit is crucial for both cybersecurity professionals and users of the affected products.
Vulnerability Summary
CVE ID: CVE-2025-5794
Severity: Critical (8.8 CVSS Score)
Attack Vector: Remote
Privileges Required: None
User Interaction: None
Impact: System compromise or data leakage
Affected Products
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Product | Affected Versions
Tenda AC5 | 15.03.06.47
How the Exploit Works
The exploit works by manipulating the argument list in the formSetPPTPUserList function. This manipulation leads to a buffer overflow, which is a condition where more data is put into a buffer than it can handle. This causes the extra data to overflow into adjacent memory spaces, potentially overwriting other data or causing the system to crash. In this case, the buffer overflow could enable an attacker to execute arbitrary code, potentially leading to system compromise or data leakage.
Conceptual Example Code
Here is a conceptual example of how the vulnerability might be exploited, using a malicious HTTP request:
POST /goform/setPptpUserList HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
list=OVERFLOWING_DATA_HEREIn this example, the OVERFLOWING_DATA_HERE would be replaced by an excessively long string intended to overflow the buffer in the formSetPPTPUserList function.
The exact structure and content of the overflow data would depend on the specifics of the target system and the goals of the attack.
Recommended Mitigation
The best course of action to protect your systems from this vulnerability is to apply the vendor’s patch. If the patch is not yet available or cannot be applied immediately, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) could serve as a temporary mitigation measure. These tools can help detect and block exploit attempts, although they cannot fully eliminate the vulnerability. Regular patching and system updates should be part of your cybersecurity strategy to prevent exploitation of known vulnerabilities like CVE-2025-5794.