Microsoft Exchange FederationTrust Deserialization of Untrusted Data NTLM Relay Vulnerability

2023-11-1500:00:00

Piotr Bazydlo (@chudypb) of Trend Micro Zero Day Initiative

www.zerodayinitiative.com

microsoft exchange

ntlm relay

authentication

serializationtypeconverter

untrusted data

system context

7.1 High

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

23.4%

JSON

This vulnerability allows remote attackers to relay NTLM credentials on affected installations of Microsoft Exchange. Authentication is required to exploit this vulnerability. The specific flaw exists within the SerializationTypeConverter class. The issue results from the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to relay NTLM credentials in the context of SYSTEM.