(Pwn2Own) Microsoft Exchange Server Missing Check of Message Integrity Vulnerability
Vulnerability Details
This vulnerability allows network-adjacent attackers to tamper with update data on affected installations of Microsoft Exchange Server. User interaction is required to exploit this vulnerability.
The specific flaw exists within the handling of Exchange Server Help updates. The issue results from a missing integrity check on update downloads. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of 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-2021-31209
Disclosure Timeline
- 2021-04-08 - Vulnerability reported to vendor
- 2021-05-26 - Coordinated public release of advisory
Credit
Steven Seeley (mr_me) of Source Incite
