Privilege escalation in Microsoft Exchange Server

1) Man-in-the-middle attack

EUVDB-ID: #VU15841

Risk: Low

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2018-8581

CWE-ID: CWE-300 - Channel Accessible by Non-Endpoint ('Man-in-the-Middle')

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain elevated privileges on the target system.

The vulnerability exists due to use of a registry key exists called HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlLsa and lack of loopback check. A remote unauthenticated attacker can conduct a man-in-the-middle attack to forward an authentication request to a Microsoft Exchange Server, thereby allowing impersonation of another Exchange user and gain SYSTEM privileges.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Microsoft Exchange Server: 2010 - 2019 RTM 15.02.0221.012

External links

http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8581

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.