Stack Buffer Overflow in D-Link DIR-513 WAN Wizard Module

Executive Summary

CVE-2025-70243 is a stack buffer overflow vulnerability found in the D-Link DIR-513 router, specifically in firmware version v1.10. The vulnerability exists in the component handling the endpoint goform/formSetWAN_Wizard534, where the curTime parameter is improperly processed.

The overflow occurs due to unsafe usage of the sprintf function in the code path goform/formSetWAN_Wizard534.curTime=>v3=>sprintf, allowing an attacker to send an excessively long curTime value via a POST request to /goform/formSetWAN_Wizard534.

This can lead to memory corruption on the stack, potentially enabling arbitrary code execution or denial of service.

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Detection Guidance

[{'type': 'paragraph', 'content': 'This vulnerability can be detected by monitoring for POST requests to the endpoint /goform/formSetWAN_Wizard534 that contain an unusually long curTime parameter.'}, {'type': 'paragraph', 'content': 'A practical detection method is to capture network traffic and filter for such POST requests with oversized curTime values, which may indicate an attempt to exploit the stack buffer overflow.'}, {'type': 'list_item', 'content': 'Use a network packet capture tool like tcpdump or Wireshark to monitor traffic to the router.'}, {'type': 'list_item', 'content': "Example tcpdump command to capture relevant HTTP POST requests: tcpdump -i <interface> -A 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep 'POST /goform/formSetWAN_Wizard534'"}, {'type': 'list_item', 'content': 'Alternatively, use curl or similar tools to test the endpoint by sending a POST request with a very long curTime parameter to check if the device responds abnormally.'}] [1]

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Impact Analysis

This vulnerability can impact you by allowing an attacker to cause memory corruption on the device running the vulnerable firmware.

• Arbitrary code execution: An attacker could execute malicious code on the router.
• Denial of service: The router could crash or become unresponsive due to the overflow.

Such impacts could compromise the security and availability of your network device.

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Compliance Impact

I don't know

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Mitigation Strategies

[{'type': 'paragraph', 'content': "Immediate mitigation steps include restricting access to the vulnerable endpoint and avoiding exposure of the router's management interface to untrusted networks."}, {'type': 'paragraph', 'content': 'Since the vulnerability arises from unsafe handling of the curTime parameter in firmware version v1.10, updating the router firmware to a patched version (if available) is the most effective mitigation.'}, {'type': 'paragraph', 'content': 'If a firmware update is not available, consider disabling remote management or placing the device behind a firewall to limit access.'}, {'type': 'paragraph', 'content': 'Monitoring for suspicious POST requests to /goform/formSetWAN_Wizard534 and blocking them can also help reduce risk.'}] [1]

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