CVE-2025-6487: Critical Stack-Based Buffer Overflow Vulnerability in TOTOLINK A3002R Routers
TOTOLINK A3002R routers are facing a critical security vulnerability that could allow attackers to remotely execute code on affected devices. Tracked as CVE-2025-6487, this flaw is a stack-based buffer overflow in the formRoute function. This blog post provides a detailed analysis of the vulnerability, its potential impact, and recommendations for mitigating the risk.
Vulnerability Details
- CVE ID: CVE-2025-6487
- Description: A stack-based buffer overflow vulnerability exists in the
formRoutefunction of TOTOLINK A3002R version 1.1.1-B20200824.0128. By manipulating thesubnetargument, an attacker can overwrite parts of the stack, potentially leading to arbitrary code execution. - CVSS Score: 8.8 (High)
- CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CVSS Explanation: This vulnerability is remotely exploitable (AV:N) with low attack complexity (AC:L). An attacker with low privileges (PR:L) can exploit it without user interaction (UI:N) to achieve high confidentiality (C:H), integrity (I:H), and availability (A:H) impact on the affected system.
- Exploit Requirements: An attacker needs to be authenticated to the router's web interface, even with low-level privileges.
- Affected Vendor: TOTOLINK
- Affected Product: A3002R
- Affected Version: 1.1.1-B20200824.0128
- CWE: CWE-121 - Stack-based Buffer Overflow
- CWE Explanation: Stack-based buffer overflows occur when a program writes data beyond the allocated buffer size on the stack. This can overwrite adjacent memory locations, potentially leading to program crashes or, in more severe cases, arbitrary code execution.
Timeline of Events
- 2025-06-22: Vulnerability publicly disclosed.
- 2025-06-22: CVE ID assigned (CVE-2025-6487).
Exploitability & Real-World Risk
The existence of a public proof-of-concept (PoC) exploit significantly increases the risk associated with CVE-2025-6487. Attackers can leverage this exploit to gain unauthorized access to vulnerable routers. In a real-world scenario, a successful exploit could allow an attacker to:
- Intercept network traffic
- Modify router settings (e.g., DNS, firewall)
- Install malware on connected devices
- Use the router as a botnet node
Given the widespread use of TOTOLINK routers, this vulnerability poses a significant threat to home and small business networks.
Recommendations
Users of TOTOLINK A3002R routers are strongly advised to take the following steps:
- Check for Firmware Updates: Visit the TOTOLINK website and check for available firmware updates for your router model. Apply any updates that address this vulnerability.
- Disable Remote Management: If you don't need to access your router remotely, disable remote management features. This reduces the attack surface.
- Use Strong Passwords: Ensure that you are using a strong, unique password for your router's web interface.
- Monitor Network Traffic: Keep an eye on your network traffic for any unusual activity.
Technical Insight
The vulnerability lies in the insufficient bounds checking when handling the subnet argument passed to the formRoute function. By providing a subnet string longer than the allocated buffer on the stack, an attacker can overwrite adjacent memory regions. This allows the attacker to control the program's execution flow and inject malicious code.
Credit to Researcher(s)
This vulnerability was discovered and reported by wudipjq.
References
Tags
#CVE-2025-6487 #TOTOLINK #A3002R #RouterVulnerability #StackOverflow #RemoteCodeExecution
Summary: A critical stack-based buffer overflow vulnerability (CVE-2025-6487) affects TOTOLINK A3002R routers, allowing remote attackers with low privileges to potentially execute arbitrary code. A public proof-of-concept exploit exists, increasing the risk. Users are advised to update firmware, disable remote management, and use strong passwords.
CVE ID: CVE-2025-6487
Risk Analysis: Successful exploitation of this vulnerability can lead to complete control of the affected router, allowing attackers to intercept network traffic, modify router settings, install malware, or use the router as a botnet node. This poses a significant risk to home and small business networks.
Recommendation: Update the router's firmware to the latest version. Disable remote management if not needed. Use a strong and unique password for the router's web interface. Monitor network traffic for any unusual activity.
Timeline
- 2025-06-22: Vulnerability publicly disclosed
- 2025-06-22: CVE ID assigned (CVE-2025-6487)