Advisory Details

December 22nd, 2021

D-Link DAP-2020 webproc var:page Stack-based Buffer Overflow Remote Code Execution Vulnerability

ZDI-21-979
ZDI-CAN-13271

CVE ID CVE-2021-34863
CVSS SCORE 8.8, AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AFFECTED VENDORS D-Link
AFFECTED PRODUCTS DAP-2020
VULNERABILITY DETAILS

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of D-Link DAP-2020 routers. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the handling of the var:page parameter provided to the webproc endpoint. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root.

ADDITIONAL DETAILS D-Link has issued an update to correct this vulnerability. More details can be found at:
https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10201
DISCLOSURE TIMELINE
  • 2021-03-12 - Vulnerability reported to vendor
  • 2021-12-22 - Coordinated public release of advisory
  • 2021-12-22 - Advisory Updated
CREDIT chung96vn & Quang Nguyen (aka sovietw0rm) of Vietnam National Cyber Security Center (NCSC Vietnam)
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