CVE-2021-28482

Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-28480, CVE-2021-28481, CVE-2021-28483.

Recent assessments:

zeroSteiner at June 03, 2021 1:07pm UTC reported:

This vulnerability is a deserialization flaw in Exchange’s MeetingPollProposeOptionsPayload.GetRequests() method. This method can be triggered with an HTTP request and when issued a specially crafted XML payload, can lead to OS command execution within the context of the w3wp.exe process which has SYSTEM level privileges.

The XML payload is a .NET serialized object which contains the ObjectDataProvider chain from YSoSerial.NET and the DataContractSerializer formatter. The payload needs to be crafted to be compatible with the way in which Exchange deserializes it.

Since many users have sufficient access to authenticate to Exchange, this could easily be used in conjunction with a phishing or password guessing attack and lead to an initial breach.

There was a blog detailing this vulnerability and a PoC written by the same author. The PoC is non-functional without being edited.

Assessed Attacker Value: 4
Assessed Attacker Value: 4Assessed Attacker Value: 3