Executive Summary

[{'type': 'paragraph', 'content': 'CVE-2025-70239 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_Wizard55 and is triggered via the "curTime" parameter.'}, {'type': 'paragraph', 'content': 'The overflow occurs because the input provided in the "curTime" parameter is not properly limited in size before being processed by a vulnerable call to sprintf. This improper handling allows an attacker to overwrite the stack memory.'}, {'type': 'paragraph', 'content': 'A proof-of-concept exploit involves sending an excessively long string in the "curTime" parameter via an HTTP POST request to the /goform/formSetWAN_Wizard55 endpoint, causing the buffer overflow.'}] [1]

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Impact Analysis

This vulnerability could potentially allow an attacker to execute remote code on the affected D-Link DIR-513 router or cause a denial of service condition.

Remote code execution means an attacker could gain control over the device, potentially manipulating its functions or using it as a foothold into a network.

Denial of service could disrupt the normal operation of the router, causing network outages or degraded performance.

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Compliance Impact

I don't know

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Detection Guidance

[{'type': 'paragraph', 'content': 'This vulnerability can be detected by monitoring HTTP POST requests sent to the endpoint /goform/formSetWAN_Wizard55 on the D-Link DIR-513 router firmware v1.10.'}, {'type': 'paragraph', 'content': 'Specifically, detection involves checking for unusually long or malformed values in the "curTime" parameter within these POST requests, as this parameter triggers the stack buffer overflow.'}, {'type': 'paragraph', 'content': 'A practical approach is to capture network traffic and filter for POST requests to /goform/formSetWAN_Wizard55, then inspect the "curTime" parameter length.'}, {'type': 'list_item', 'content': "Use a network packet capture tool like tcpdump or Wireshark to capture traffic on the router's interface."}, {'type': 'list_item', 'content': "Example tcpdump command to capture HTTP POST requests to the vulnerable endpoint: tcpdump -A -s 0 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)'"}, {'type': 'list_item', 'content': 'Filter captured traffic for POST requests containing "/goform/formSetWAN_Wizard55" and inspect the "curTime" parameter for abnormally long strings.'}, {'type': 'paragraph', 'content': 'Alternatively, use web application firewall (WAF) logs or intrusion detection system (IDS) signatures to detect attempts to exploit this vulnerability by looking for oversized "curTime" parameter values in POST requests.'}] [1]

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Mitigation Strategies

[{'type': 'paragraph', 'content': 'Immediate mitigation steps include restricting access to the vulnerable endpoint and filtering malicious traffic targeting the "curTime" parameter.'}, {'type': 'list_item', 'content': 'Block or limit external access to the /goform/formSetWAN_Wizard55 endpoint on the D-Link DIR-513 router.'}, {'type': 'list_item', 'content': 'Implement input validation or filtering on the router or network perimeter to reject HTTP POST requests with excessively long "curTime" parameter values.'}, {'type': 'list_item', 'content': 'Monitor network traffic for exploitation attempts and respond by blocking offending IP addresses.'}, {'type': 'paragraph', 'content': 'Ultimately, updating the router firmware to a version that patches this vulnerability is recommended once available.'}] [1]

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