CVE-2025-5912 in DIR-632
Summary
by MITRE • 06/10/2025
A vulnerability was found in D-Link DIR-632 FW103B08. It has been declared as critical. This vulnerability affects the function do_file of the component HTTP POST Request Handler. The manipulation leads to stack-based buffer overflow. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used. This vulnerability only affects products that are no longer supported by the maintainer.
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Analysis
by VulDB Data Team • 06/16/2025
The vulnerability identified as CVE-2025-5912 represents a critical stack-based buffer overflow flaw within the D-Link DIR-632 wireless router firmware version FW103B08. This security weakness resides in the HTTP POST Request Handler component, specifically within the do_file function that processes incoming web requests. The flaw stems from inadequate input validation and bounds checking mechanisms that fail to properly sanitize user-supplied data before processing it within fixed-size memory buffers. The affected device's web interface receives HTTP POST requests containing file upload parameters, which are then handled by the vulnerable do_file function. When maliciously crafted data exceeds the allocated buffer space, it overflows into adjacent memory regions, potentially allowing attackers to overwrite critical program variables, return addresses, or function pointers. This type of vulnerability falls under CWE-121 Stack-based Buffer Overflow, a well-documented weakness that has been exploited in numerous network device attacks. The remote exploitation capability means that attackers can trigger this vulnerability without requiring physical access to the device, making it particularly dangerous for network infrastructure components. The vulnerability's exploitation requires sending specially crafted HTTP POST requests to the router's web interface, which can be accomplished from any network location with access to the device's IP address and web management interface. The public disclosure of exploitation techniques further increases the risk, as malicious actors can readily develop automated tools to exploit this weakness.
The operational impact of CVE-2025-5912 extends beyond simple denial of service or data corruption, as stack-based buffer overflows can potentially enable arbitrary code execution on the affected device. Successful exploitation could allow remote attackers to gain full control over the router's operating system, enabling them to modify network configurations, install backdoors, redirect traffic, or use the device as a pivot point for attacks against other systems within the local network. This vulnerability particularly threatens network security infrastructure, as routers serve as critical gateways between internal networks and external internet access. The attack surface is further expanded by the fact that many users may not be aware that their unsupported devices are vulnerable, creating a persistent security risk that can remain undetected for extended periods. The exploitation of this vulnerability aligns with tactics described in the MITRE ATT&CK framework under the T1059.007 technique for Command and Scripting Interpreter, where attackers can execute arbitrary commands on compromised systems. Additionally, the vulnerability's impact on network infrastructure relates to T1566.001 for Phishing with Malicious Attachments and T1071.001 for Application Layer Protocol, as attackers can manipulate the router's behavior to redirect traffic or intercept communications.
Given that D-Link has discontinued support for the DIR-632 model, users face limited official remediation options for this vulnerability. The lack of firmware updates or security patches from the vendor significantly increases the risk exposure for affected users, as they cannot rely on official vendor support to address the flaw. Organizations and individuals should consider immediate mitigation strategies, including network segmentation to isolate vulnerable devices, disabling unnecessary services or web interfaces, and implementing network monitoring to detect potential exploitation attempts. The vulnerability's critical severity classification indicates that the risk of exploitation is high, particularly in environments where network devices are not properly secured or regularly updated. Users should also consider replacing unsupported devices with newer models that receive ongoing security support and firmware updates. Network administrators should implement intrusion detection systems to monitor for suspicious HTTP POST requests that might indicate exploitation attempts, and should consider implementing access controls that limit who can reach the router's web management interface. The combination of public exploit availability and end-of-life status for this device creates an urgent security concern that requires immediate attention from affected organizations. The vulnerability demonstrates the importance of maintaining up-to-date network equipment and the dangers associated with using unsupported devices in production environments.