CVE-2017-14515 in W15E
Summary
by MITRE
Heap-based Buffer Overflow on Tenda W15E devices before 15.11.0.14 allows remote attackers to cause a denial of service (temporary HTTP outage and forced logout) via unspecified vectors.
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Analysis
by VulDB Data Team • 11/17/2019
The heap-based buffer overflow vulnerability identified as CVE-2017-14515 affects Tenda W15E wireless routers and other devices running firmware versions prior to 15.11.0.14. This critical security flaw resides within the device's web interface handling mechanism, specifically in how it processes incoming HTTP requests. The vulnerability manifests when the router receives malformed input data through its HTTP server component, creating an exploitable condition in the heap memory management system. The affected devices operate under a typical embedded system architecture where the web server component manages user authentication and configuration access, making it a prime target for remote exploitation. The vulnerability has been classified under CWE-121 as a heap-based buffer overflow, which represents a well-known class of memory corruption vulnerabilities that can lead to unpredictable behavior and system instability.
The technical implementation of this vulnerability involves the improper handling of user-supplied data within the HTTP request processing pipeline of the router's web interface. When remote attackers send specially crafted HTTP requests containing oversized or malformed input parameters, the device's memory allocation routines fail to properly validate the input size before copying it into fixed-size heap buffers. This results in memory corruption that can cause the web server process to crash or behave erratically. The specific attack vectors remain unspecified in the public advisory, but typically such vulnerabilities arise from insufficient bounds checking in string manipulation functions, particularly when processing form data, URL parameters, or HTTP headers. The affected implementation likely uses standard C library functions such as strcpy, strcat, or sprintf without adequate input validation, creating opportunities for attackers to overwrite adjacent heap memory regions.
The operational impact of CVE-2017-14515 manifests as temporary denial of service conditions that disrupt normal network operations and user access to the device's administrative interface. Remote attackers can trigger the buffer overflow condition to cause the web server to crash, resulting in immediate HTTP service outages that prevent legitimate users from accessing the router configuration pages. Additionally, the vulnerability forces automatic user logouts, requiring administrators to re-authenticate before regaining access to the device. This disruption can be particularly problematic in enterprise environments where router accessibility is critical for network management and security policy enforcement. The temporary nature of the outage means that the device typically recovers automatically after the web server process terminates and restarts, but the frequency and timing of such disruptions can significantly impact network availability and user productivity. The vulnerability does not appear to enable arbitrary code execution or persistent system compromise, but the denial of service impact can be substantial in mission-critical deployments.
Mitigation strategies for CVE-2017-14515 should prioritize firmware updates from Tenda, as the vendor has released version 15.11.0.14 to address the heap overflow condition. Network administrators should implement immediate patch management procedures to upgrade all affected devices to the patched firmware versions. Additional defensive measures include implementing network segmentation to limit exposure of these devices to untrusted networks, configuring firewall rules to restrict HTTP access to the router's web interface to trusted IP addresses only, and monitoring network traffic for unusual patterns that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1210 for exploiting weaknesses in remote services, and organizations should consider implementing intrusion detection systems to monitor for potential exploitation attempts. Regular security assessments of network infrastructure should include verification of device firmware versions and patch compliance to prevent similar vulnerabilities from remaining unaddressed in the network environment.