#VU80672 Deserialization of Untrusted Data in Microsoft Exchange Server - CVE-2023-36756

Vulnerability identifier: #VU80672

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-2023-36756

CWE-ID: CWE-502

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 execute arbitrary code on the target system.

The vulnerability exists due to insecure input validation when processing serialized data within the ApprovedApplicationCollection class. A remote user can pass specially crafted data to the application and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

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

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External links
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-36756
https://techcommunity.microsoft.com/t5/exchange-team-blog/released-august-2023-exchange-server-security-updates/ba-p/3892811
https://www.zerodayinitiative.com/advisories/ZDI-23-1419/

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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.