Main Vulnerability Database Vulnerabilities #VU53082

Improper validation of integrity check value in Microsoft Exchange Server - CVE-2021-31209

Published: May 11, 2021 / Updated: June 1, 2021

Vulnerability identifier: #VU53082

CSH Severity: Medium

CVSS v4 BT: 6.3 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-31209

CWE-ID: CWE-354

Exploitation vector: Adjecent network

Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to bypass integrity checks.

The vulnerability exists within the handling of Exchange Server Help updates. A remote attacker on the local network can bypass integrity check on update downloads.

Affected software

Microsoft Exchange Server

How to mitigate CVE-2021-31209

Install updates from vendor's website.

External References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31209
https://www.zerodayinitiative.com/advisories/ZDI-21-615/

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