CVE-2025-15255

Comprehensive Technical Analysis of CVE-2025-15255

1. Vulnerability Assessment and Severity Evaluation

CVE ID: CVE-2025-15255 CVSS Score: 9.8

The vulnerability in question affects the Tenda W6-S 1.0.0.4(510) firmware, specifically within the /bin/httpd file of the R7websSsecurityHandler component. The issue involves a stack-based buffer overflow that can be triggered by manipulating the Cookie argument. This vulnerability is severe, as indicated by its high CVSS score of 9.8. The severity is due to the potential for remote exploitation, which can lead to arbitrary code execution, system crashes, or unauthorized access to sensitive information.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Remote Exploitation: The vulnerability can be exploited remotely, meaning an attacker does not need physical access to the device.
• Network-Based Attacks: Given that the vulnerability resides in the HTTP daemon, attackers can exploit it over the network, potentially through crafted HTTP requests.

Exploitation Methods:

• Buffer Overflow: By sending a specially crafted HTTP request with a manipulated Cookie header, an attacker can cause a stack-based buffer overflow.
• Code Execution: If successful, the attacker could execute arbitrary code on the affected device, leading to full control over the system.
• Denial of Service (DoS): Even if code execution is not achieved, the attacker could cause the device to crash, resulting in a denial of service.

3. Affected Systems and Software Versions

Affected Systems:

• Tenda W6-S devices running firmware version 1.0.0.4(510).

Software Versions:

• The vulnerability specifically affects the /bin/httpd file within the R7websSsecurityHandler component of the firmware.

4. Recommended Mitigation Strategies

Immediate Actions:

• Firmware Update: Immediately update the firmware to a version that addresses this vulnerability. If an update is not available, consider disabling remote access to the device.
• Network Segmentation: Isolate the affected devices on a separate network segment to limit exposure.
• Firewall Rules: Implement strict firewall rules to block unauthorized access to the device.

Long-Term Strategies:

• Regular Patching: Ensure that all devices are regularly updated with the latest firmware and security patches.
• Intrusion Detection Systems (IDS): Deploy IDS to monitor for suspicious network activity targeting the HTTP daemon.
• Security Audits: Conduct regular security audits and vulnerability assessments to identify and mitigate potential risks.

5. Impact on Cybersecurity Landscape

Broader Implications:

• IoT Security: This vulnerability highlights the ongoing challenges in securing Internet of Things (IoT) devices, which are often deployed with minimal security features.
• Supply Chain Risks: It underscores the importance of supply chain security, as vulnerabilities in third-party components can have significant downstream effects.
• Public Disclosure: The public disclosure of the exploit increases the risk of widespread attacks, emphasizing the need for prompt mitigation.

6. Technical Details for Security Professionals

Vulnerability Details:

• Component: R7websSsecurityHandler
• File: /bin/httpd
• Trigger: Manipulation of the Cookie argument in HTTP requests.

Exploit Characteristics:

• Stack-Based Buffer Overflow: The vulnerability allows an attacker to overwrite the stack, potentially leading to code execution or system crashes.
• Remote Access: The attack can be launched remotely, making it a high-risk vulnerability.

Detection and Response:

• Log Analysis: Monitor HTTP request logs for unusual patterns or repeated attempts to manipulate the Cookie header.
• Behavioral Analysis: Use behavioral analysis tools to detect anomalous behavior that may indicate an exploitation attempt.
• Incident Response: Have an incident response plan in place to quickly address any detected exploitation attempts.

Conclusion: CVE-2025-15255 represents a critical vulnerability in Tenda W6-S devices that requires immediate attention. Organizations should prioritize updating affected devices and implementing robust security measures to mitigate the risk of exploitation. The broader cybersecurity community should continue to focus on improving the security of IoT devices and third-party components to reduce the likelihood of similar vulnerabilities in the future.