CVE-2024-9569: D-Link DIR-619L Buffer Overflow Vulnerability

CVE-2024-9569 is a critical buffer overflow vulnerability in D-Link DIR-619L B1 2.06 firmware affecting the formEasySetPassword function. Attackers can exploit this remotely to compromise the router. This article covers technical details, affected versions, impact assessment, and mitigation strategies.

CVE-2024-9569 Overview

CVE-2024-9569 is a buffer overflow vulnerability in the D-Link DIR-619L B1 router running firmware version 2.06. The flaw resides in the formEasySetPassword function handled by the /goform/formEasySetPassword endpoint. Attackers can trigger the overflow by manipulating the curTime argument. The issue is classified under CWE-120, classic buffer copy without checking input size. A public proof-of-concept has been disclosed, increasing exposure risk for internet-facing devices.

Critical Impact
Remote attackers with low privileges can corrupt router memory through the curTime parameter, enabling denial of service or potential arbitrary code execution on affected D-Link DIR-619L devices.

Affected Products

D-Link DIR-619L hardware revision B1
D-Link DIR-619L firmware version 2.06b1
End-of-life D-Link consumer routers using the same web management stack

Discovery Timeline

2024-10-07 - CVE-2024-9569 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-9569

Vulnerability Analysis

The vulnerability exists in the router's HTTP administration interface. The formEasySetPassword handler processes password setup requests submitted to /goform/formEasySetPassword. The handler reads the curTime query parameter without validating its length before copying it into a fixed-size stack buffer. Sending an oversized curTime value overflows the buffer and corrupts adjacent memory, including saved return addresses on MIPS-based D-Link firmware. Successful exploitation can crash the httpd process or redirect execution flow, depending on the attacker's control over the overwritten memory.

Root Cause

The root cause is missing bounds checking in the formEasySetPassword routine. The function trusts client-supplied input and performs an unbounded string copy operation on the curTime argument. This is a textbook CWE-120 buffer copy without checking size of input, common in legacy embedded web servers written in C.

Attack Vector

Exploitation requires network access to the router's management interface and low-privilege authentication. An attacker sends a crafted HTTP request to /goform/formEasySetPassword containing an oversized curTime value. Because the management interface may be reachable from the LAN by default, any authenticated user on the local network can trigger the condition. Devices with remote administration enabled expose the endpoint to the internet, expanding the attack surface. Refer to the public proof-of-concept for exploitation specifics.

// No verified exploit code is reproduced here.
// See the linked PoC repository for technical details of the crafted HTTP request
// and the oversized curTime parameter that triggers the overflow.

Detection Methods for CVE-2024-9569

Indicators of Compromise

HTTP POST or GET requests to /goform/formEasySetPassword containing an abnormally long curTime parameter value
Unexpected reboots or httpd crashes on DIR-619L devices coinciding with management-interface access
Configuration changes to the router administrator password without a corresponding authorized session
Outbound connections from the router to unknown hosts after suspicious HTTP activity

Detection Strategies

Inspect network traffic for HTTP requests to /goform/formEasySetPassword and alert on curTime parameter values exceeding a reasonable length threshold (for example, greater than 64 bytes)
Correlate router syslog messages indicating web server restarts with recent authentication events
Baseline management-interface traffic and flag requests originating outside expected administrative subnets

Monitoring Recommendations

Forward router syslogs to a central log platform and retain HTTP access logs where the device supports them
Monitor for repeated authentication attempts followed by requests to /goform/ endpoints
Track EPSS scoring for CVE-2024-9569, currently 1.314% (68th percentile), as an early exploitation signal

How to Mitigate CVE-2024-9569

Immediate Actions Required

Disable remote (WAN-side) administration on all DIR-619L devices to block internet-based exploitation
Restrict LAN access to the router management interface to a dedicated administrative VLAN or host
Rotate the router administrator password and any credentials that may have been exposed to untrusted users
Inventory affected devices and prioritize replacement, as the DIR-619L is an end-of-life product

Patch Information

At the time of publication, no vendor-supplied firmware patch is listed for the DIR-619L B1 firmware 2.06. The DIR-619L is an end-of-life product, and D-Link typically directs customers of end-of-life hardware to migrate to a supported model. Consult the D-Link official website and regional support portals for current end-of-life guidance and replacement recommendations.

Workarounds

Place the router behind an upstream firewall that blocks inbound access to the management interface
Segment the router administrative interface from user and guest networks using VLANs
Replace the DIR-619L with a currently supported router that receives security updates
Where replacement is not immediate, keep the device isolated from untrusted users and monitor for anomalous management-interface traffic

bash

# Example: block external access to the router web UI at an upstream firewall (iptables)
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -i <wan_iface> -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -i <wan_iface> -j DROP