(Pwn2Own) Microsoft SharePoint ValidateTokenIssuer Improper Verification of Cryptographic Signature Authentication Bypass Vulnerability
June 16th, 2023
Vulnerability Details
This vulnerability allows remote attackers to bypass authentication on affected installations of Microsoft SharePoint. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the ValidateTokenIssuer method. The issue results from the lack of proper verification of a cryptographic signature. An attacker can leverage this vulnerability to bypass authentication on the system.
Additional Details
Microsoft has issued an update to correct this vulnerability. More details can be found at:
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-29357
Disclosure Timeline
- 2023-03-30 - Vulnerability reported to vendor
- 2023-06-16 - Coordinated public release of advisory
- 2024-10-25 - Advisory Updated
Credit
Nguyễn Tiến Giang (@testanull) of STAR Labs SG Pte. Ltd.
