CVE-2017-14948

Vulnerability

A buffer overflow vulnerability exists in the fileaccess.cgi binary of D-Link DIR-880L firmware version 1.08B04 and DIR-895 L/R firmware version 1.13b03. The function content_type copies the value of the CONTENT_TYPE environment variable (derived from the HTTP request header) into a fixed 256-byte stack buffer without length checking. If the header starts with boundary= followed by more than 256 characters, a stack-based buffer overflow occurs [1].

Exploitation

An attacker can exploit this vulnerability by sending a crafted HTTP request to the router's web interface. The request must include a CONTENT_TYPE header that begins with boundary= and contains at least 257 characters. No authentication is required, and the attack is performed remotely. The overflow can be leveraged to mount a Return-Oriented Programming (ROP) attack, as described in the reference [1].

Impact

Successful exploitation allows an attacker to execute arbitrary code on the affected router. This can lead to full compromise of the device, including unauthorized access to network traffic, modification of router settings, and potential lateral movement within the network. The impact is remote code execution with the privileges of the fileaccess.cgi process [1].

Mitigation

As of the publication date (2019-10-14), no official patch or firmware update has been released by D-Link to address this vulnerability. Users are advised to check the vendor's support page for any later firmware versions that may include a fix. If no update is available, consider replacing the device or implementing network-level controls to restrict access to the router's web interface [1].