#VU80670 Improper Authentication in Microsoft Exchange Server - CVE-2023-36757


| Updated: 2023-09-20

Vulnerability identifier: #VU80670

Vulnerability risk: Medium

CVSSv4.0: 6.1 [CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-36757

CWE-ID: CWE-287

Exploitation vector: Local network

Exploit availability: No

Vulnerable software:
Microsoft Exchange Server
Server applications / Mail servers

Vendor: Microsoft

Description

The vulnerability allows a remote user to compromise the affected system.

The vulnerability exists due to an error in the processing authentication requests. A remote user on the local network can obtain a victim's Net-NTLMv2 hash and perform an NTLM Relay attack against another service to authenticate as the user.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Microsoft Exchange Server: 2016 Cumulative Update 1 15.01.0396.030 - 2016 CU23 Jun23SU 15.01.2507.027, 2019 Cumulative Update 1 15.02.0330.005 - 2019 RTM 15.02.0221.012


External links
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-36757
https://techcommunity.microsoft.com/t5/exchange-team-blog/released-august-2023-exchange-server-security-updates/ba-p/3892811
https://www.zerodayinitiative.com/advisories/ZDI-23-1447/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.


Latest bulletins with this vulnerability