CVE-2024-9557 Overview
CVE-2024-9557 is a buffer overflow vulnerability in the D-Link DIR-605L router running firmware version 2.13B01 BETA. The flaw resides in the formSetWanPPPoE function within /goform/formSetWanPPPoE, where the webpage argument is processed without adequate bounds checking. Remote attackers with low-privileged access can trigger the overflow across the network. The exploit has been publicly disclosed, increasing the likelihood of opportunistic attacks against exposed devices. The DIR-605L is a legacy consumer wireless router, and this model is no longer actively supported by D-Link for firmware updates.
Critical Impact
Remote attackers can corrupt memory in the router's web management interface, potentially achieving arbitrary code execution or denial of service on affected D-Link DIR-605L devices.
Affected Products
- D-Link DIR-605L (hardware)
- D-Link DIR-605L firmware version 2.13B01 BETA
- Legacy D-Link consumer router deployments exposing the web management interface
Discovery Timeline
- 2024-10-06 - CVE-2024-9557 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-9557
Vulnerability Analysis
The vulnerability is a classic stack or heap buffer overflow [CWE-120] in the router's HTTP administration interface. The formSetWanPPPoE handler processes PPPoE (Point-to-Point Protocol over Ethernet) WAN configuration submissions from the web UI. When an attacker submits a crafted request containing an oversized webpage parameter, the handler copies the input into a fixed-size buffer without validating its length. This overwrites adjacent memory regions on the device's MIPS-based firmware runtime. Successful exploitation can corrupt control data on the stack or heap, leading to code execution in the context of the router's web server process or a device crash.
Root Cause
The root cause is missing input length validation on the webpage argument before it is copied into an internal buffer inside formSetWanPPPoE. The function relies on unsafe string handling routines with no bounds enforcement. Consumer-grade router firmware frequently reuses such patterns across /goform/ handlers, and D-Link's DIR-605L is end-of-life, so a vendor patch is unlikely.
Attack Vector
An attacker sends an HTTP POST request to /goform/formSetWanPPPoE on the router's administrative web interface, supplying an oversized value in the webpage field. The request requires authenticated but low-privileged access to the web UI. If the management interface is exposed to the WAN or reachable from a compromised LAN host, the attacker can reach the endpoint remotely. Refer to the GitHub Vulnerability Documentation and VulDB CTI ID #279364 for reproduction details.
No verified proof-of-concept code from a trusted source is included here. See the external references above for technical details on the request format and offsets.
Detection Methods for CVE-2024-9557
Indicators of Compromise
- HTTP POST requests to /goform/formSetWanPPPoE containing unusually long webpage parameter values, particularly exceeding a few hundred bytes.
- Repeated crashes, reboots, or web management interface unavailability on DIR-605L devices.
- Unexpected changes to WAN or PPPoE configuration entries in router logs.
Detection Strategies
- Inspect network traffic for POST requests targeting /goform/formSetWanPPPoE and flag payloads where the webpage field exceeds expected length.
- Correlate router syslog entries showing httpd or boa web server crashes with administrative endpoint requests.
- Deploy network intrusion detection signatures that match oversized parameter values against known D-Link /goform/ endpoints.
Monitoring Recommendations
- Forward router syslog output to a central log platform and alert on repeated web server restarts.
- Monitor for administrative access to DIR-605L devices from unexpected source IP addresses, especially external ones.
- Baseline normal PPPoE configuration change frequency and alert on anomalous submissions.
How to Mitigate CVE-2024-9557
Immediate Actions Required
- Disable remote (WAN-side) administration on the DIR-605L web management interface.
- Restrict LAN access to the router's admin interface to a management VLAN or trusted hosts only.
- Replace end-of-life DIR-605L devices with a currently supported router model, since D-Link is unlikely to issue a firmware fix.
- Rotate the router administrator credentials to reduce the risk of low-privileged exploitation.
Patch Information
No vendor patch is listed in the enriched CVE data for the DIR-605L 2.13B01 BETA firmware. The DIR-605L is a legacy consumer product, and the D-Link Official Website should be checked for end-of-life notices and any successor firmware advisories. Until a fix is confirmed, treat affected devices as unpatched and prioritize replacement.
Workarounds
- Block inbound traffic to the router's HTTP/HTTPS management ports from untrusted networks at the perimeter.
- Segment the DIR-605L onto an isolated network so a compromise cannot pivot to internal assets.
- Require VPN access before permitting administrative connections to the router.
# Example: block WAN-side access to the router admin interface using an upstream firewall
iptables -A FORWARD -p tcp -d <ROUTER_LAN_IP> --dport 80 -i <WAN_IF> -j DROP
iptables -A FORWARD -p tcp -d <ROUTER_LAN_IP> --dport 443 -i <WAN_IF> -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
