Advisory Details

March 1st, 2022

(0Day) Microsoft .NET Link Following Denial-of-Service Vulnerability

ZDI-22-426
ZDI-CAN-14528

CVE ID
CVSS SCORE 6.1, (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H)
AFFECTED VENDORS Microsoft
AFFECTED PRODUCTS .NET
VULNERABILITY DETAILS

This vulnerability allows local attackers to create a denial-of-service condition on affected installations of Microsoft .NET. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the .NET installer. By creating a symbolic link, an attacker can abuse the installer to overwrite a file. An attacker can leverage this vulnerability to create a denial-of-service condition on the system.

ADDITIONAL DETAILS

This vulnerability is being disclosed publicly without a patch in accordance with the ZDI 120 day deadline.

07/07/21 – ZDI reported the vulnerabilities to the vendor
07/07/21 – The vendor acknowledged the report
07/15/21 – The vendor  requested technical clarification
07/16/21 – ZDI provided additional evidence
07/21/21 – The vendor  requested technical clarification
07/23/21 – ZDI provided additional evidence
07/30/21 – The vendor confirmed the behavior reported
09/24/21 – The vendor requested an extension until 01/11/22
09/28/21 – ZDI approved on an extension until 01/11/22
01/12/22 – ZDI requested an update
02/18/22 – ZDI requested an update
02/18/22 – The vendor clarified that the issues have been fixed on 01/11/22
02/22/22 – ZDI communicated that the issues were still vulnerable on the latest version and notified the vendor of the intention to publish the cases as 0-day advisories on 02/28/22

-- Mitigation:
Given the nature of the vulnerability the only salient mitigation strategy is to restrict interaction with the application.


DISCLOSURE TIMELINE
  • 2021-07-07 - Vulnerability reported to vendor
  • 2022-03-01 - Coordinated public release of advisory
CREDIT Michael DePlante (@izobashi) of Trend Micro's Zero Day Initiative
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