CVE-2025-2618: D-Link DAP-1620 Buffer Overflow Flaw

CVE-2025-2618 Overview

A critical heap-based buffer overflow vulnerability has been discovered in D-Link DAP-1620 firmware version 1.03. This vulnerability exists in the set_ws_action function within the /dws/api/ path handler component. The flaw allows remote attackers to exploit improper memory handling, potentially leading to arbitrary code execution on affected devices. This vulnerability is particularly concerning as it affects products that are no longer supported by the maintainer, meaning no official patches will be released.

Critical Impact

Remote attackers can exploit this heap-based buffer overflow vulnerability over the network without authentication, potentially gaining complete control of the affected D-Link DAP-1620 device. The device is end-of-life with no vendor support available.

Affected Products

• D-Link DAP-1620 Firmware version 1.03
• D-Link DAP-1620 Hardware (all revisions)

Discovery Timeline

• 2025-03-22 - CVE-2025-2618 published to NVD
• 2025-03-26 - Last updated in NVD database

Technical Details for CVE-2025-2618

Vulnerability Analysis

This vulnerability is classified under CWE-787 (Out-of-bounds Write) and CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw resides in the set_ws_action function, which is responsible for handling API requests through the /dws/api/ path handler. When processing malicious input, the function fails to properly validate buffer boundaries before writing data to heap memory, resulting in a classic heap-based buffer overflow condition.

The vulnerability can be exploited remotely over the network without requiring any authentication or user interaction. An attacker can craft malicious requests to the vulnerable endpoint, causing memory corruption that could lead to denial of service or arbitrary code execution with the privileges of the affected service.

Root Cause

The root cause of this vulnerability stems from insufficient bounds checking in the set_ws_action function. When processing incoming API requests, the function allocates a fixed-size buffer on the heap but fails to validate that user-supplied data fits within the allocated memory region. This allows attackers to overflow the buffer with excessive data, corrupting adjacent heap memory structures and potentially hijacking program execution flow.

Attack Vector

The attack can be launched remotely over the network against the device's web interface. An attacker would target the /dws/api/ endpoint with specially crafted HTTP requests designed to trigger the buffer overflow in the set_ws_action function. Since no authentication is required to reach the vulnerable code path, any attacker with network access to the device can attempt exploitation.

The vulnerability has been publicly disclosed and exploit information is available. The attack requires no privileges, no user interaction, and has low complexity, making it highly exploitable in real-world scenarios.

Detection Methods for CVE-2025-2618

Indicators of Compromise

• Unusual HTTP requests targeting the /dws/api/ endpoint with abnormally large payloads
• Device crashes, unexpected reboots, or unresponsive behavior following network activity
• Anomalous outbound network connections from the DAP-1620 device indicating potential compromise
• Modified device configurations or new administrative accounts not created by legitimate users

Detection Strategies

• Monitor network traffic for HTTP requests to D-Link DAP-1620 devices with unusually large Content-Length headers or payloads
• Implement intrusion detection rules to flag requests to /dws/api/ endpoints containing suspicious patterns
• Deploy network segmentation to isolate IoT devices and enable easier monitoring of anomalous traffic
• Review device logs for crash events or service restarts that may indicate exploitation attempts

Monitoring Recommendations

• Establish baseline network behavior for DAP-1620 devices and alert on deviations
• Configure SIEM rules to correlate multiple indicators such as large API requests followed by device reboots
• Monitor for known exploit signatures referenced in the VulDB CTI database

How to Mitigate CVE-2025-2618

Immediate Actions Required

• Immediately replace affected D-Link DAP-1620 devices with currently supported network equipment, as this device is end-of-life
• If replacement is not immediately possible, isolate the device from untrusted networks and restrict access to the management interface
• Disable remote management access and limit connectivity to the device's web interface
• Implement network-level access controls to restrict which hosts can communicate with the device

Patch Information

No official patch is available for this vulnerability. D-Link has confirmed that the DAP-1620 is no longer supported and will not receive security updates. The vendor recommends retiring affected devices and replacing them with current-generation products that receive ongoing security support. Refer to the D-Link Official Website for information on supported replacement products.

Workarounds

• Place the DAP-1620 behind a firewall that blocks external access to the /dws/api/ endpoint
• Configure access control lists (ACLs) to permit management interface access only from trusted administrator IP addresses
• Disable WAN-side management features to prevent remote exploitation from the internet
• Consider using a VPN for any required remote administration, limiting direct exposure of the device

# Example firewall rule to block external access to vulnerable endpoint
# (Adjust interface and network values for your environment)
iptables -A FORWARD -d <DAP-1620-IP> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <DAP-1620-IP> -p tcp --dport 443 -j DROP

# Allow only trusted management subnet
iptables -A FORWARD -s 192.168.1.0/24 -d <DAP-1620-IP> -p tcp --dport 80 -j ACCEPT