CVE-2025-8168 Overview
A critical buffer overflow vulnerability has been identified in the D-Link DIR-513 router firmware version 1.10. The vulnerability exists in the websAspInit function within the /goform/formSetWanPPPoE endpoint. Improper handling of the curTime argument allows an attacker to trigger a buffer overflow condition, potentially leading to arbitrary code execution or denial of service. This vulnerability can be exploited remotely over the network, making it a significant risk for exposed devices. The exploit has been publicly disclosed, increasing the urgency for affected users to take protective measures.
Critical Impact
Remote attackers can exploit this buffer overflow vulnerability to potentially execute arbitrary code or crash affected D-Link DIR-513 routers, compromising network security and device availability.
Affected Products
- D-Link DIR-513 Firmware version 1.10
- D-Link DIR-513 Hardware Revision A1
- D-Link DIR-513 Hardware Revision A2
Discovery Timeline
- 2025-07-25 - CVE-2025-8168 published to NVD
- 2025-07-31 - Last updated in NVD database
Technical Details for CVE-2025-8168
Vulnerability Analysis
This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-787 (Out-of-bounds Write). The websAspInit function in the D-Link DIR-513 firmware fails to properly validate the length of the curTime argument before copying it into a fixed-size buffer. When a crafted request with an oversized curTime value is sent to the /goform/formSetWanPPPoE endpoint, the function writes beyond the allocated buffer boundaries, corrupting adjacent memory regions.
The vulnerability is particularly concerning because it affects a network-accessible endpoint, allowing unauthenticated or low-privileged attackers to trigger the overflow condition remotely. Successful exploitation could allow an attacker to overwrite critical memory structures, potentially hijacking the execution flow to run malicious code or causing the device to crash.
It is important to note that this vulnerability affects products that are no longer supported by D-Link, meaning no official security patches will be released by the vendor.
Root Cause
The root cause of this vulnerability is insufficient input validation in the websAspInit function. The function accepts user-controlled input through the curTime parameter without properly checking its length against the destination buffer size. This classic buffer overflow condition arises from the use of unsafe memory copy operations that do not enforce boundary checks, allowing an attacker to supply an input that exceeds the expected buffer capacity.
Attack Vector
The attack can be launched remotely over the network. An attacker with low-level privileges on the network can craft a malicious HTTP request targeting the /goform/formSetWanPPPoE endpoint. By manipulating the curTime parameter to include an oversized payload, the attacker can trigger the buffer overflow condition.
The exploitation process involves:
- Identifying an exposed D-Link DIR-513 router on firmware version 1.10
- Crafting an HTTP request to the vulnerable endpoint with a maliciously oversized curTime value
- Sending the crafted request to overflow the buffer and potentially achieve code execution or denial of service
Technical details of the vulnerability are documented in the GitHub PoC Repository. Additional information is available through VulDB #317582.
Detection Methods for CVE-2025-8168
Indicators of Compromise
- Unexpected HTTP POST requests to /goform/formSetWanPPPoE with unusually long curTime parameter values
- Router crashes or unexpected reboots without administrative action
- Suspicious network traffic patterns targeting the router's web management interface
- Abnormal memory usage or process behavior on the device
Detection Strategies
- Monitor HTTP traffic to the router's web interface for requests with oversized parameters targeting the /goform/formSetWanPPPoE endpoint
- Implement network intrusion detection signatures to identify buffer overflow exploitation attempts against D-Link DIR-513 devices
- Deploy web application firewall rules to block requests with abnormally long parameter values to known vulnerable endpoints
- Conduct regular firmware version audits to identify devices running vulnerable firmware version 1.10
Monitoring Recommendations
- Enable logging on network devices to capture all traffic to and from D-Link DIR-513 routers
- Configure alerts for repeated requests to the vulnerable endpoint or requests containing suspicious payloads
- Regularly review router logs for signs of unauthorized access attempts or exploitation activity
- Implement network segmentation to isolate IoT and router devices from critical network assets
How to Mitigate CVE-2025-8168
Immediate Actions Required
- Restrict network access to the D-Link DIR-513 web management interface by implementing firewall rules to block external access
- Consider replacing the affected D-Link DIR-513 device with a currently supported router model, as this product is end-of-life
- Disable remote management features if not required for operational purposes
- Implement network-level access controls to limit which hosts can communicate with the router's management interface
Patch Information
This vulnerability affects products that are no longer supported by D-Link. No official security patch is available or expected to be released by the vendor. Users of affected devices are strongly encouraged to replace the D-Link DIR-513 with a supported router model that receives regular security updates. For vendor information, refer to the D-Link Official Site.
Workarounds
- Deploy a firewall or access control list (ACL) to block all untrusted traffic to the /goform/formSetWanPPPoE endpoint
- Place the D-Link DIR-513 behind a separate firewall that filters malicious requests before they reach the device
- Disable the web management interface entirely if remote administration is not required
- Segment the network to isolate the vulnerable router from sensitive systems and data
# Example: Block external access to router management interface using iptables
# Run on an upstream firewall protecting the D-Link DIR-513 (replace IP as needed)
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
