Vulnerability identifier: #VU66692

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2022-37451

CWE-ID: CWE-763

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Exim
Server applications / Mail servers

Vendor: Exim

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to an invalid free in pam_converse() function in auths/call_pam.c. A remote attacker can initiate the connection to the affected mail server and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Exim: 4.00 - 4.95

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External links
http://www.exim.org/static/doc/security/
http://github.com/ivd38/exim_invalid_free
http://github.com/Exim/exim/compare/exim-4.95...exim-4.96
http://lists.exim.org/lurker/message/20220625.141825.d6de6074.en.html
http://www.openwall.com/lists/oss-security/2022/08/06/1
http://github.com/Exim/exim/wiki/EximSecurity
http://cwe.mitre.org/data/definitions/762.html
http://github.com/Exim/exim/commit/51be321b27825c01829dffd90f11bfff256f7e42

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Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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