Vulnerability identifier: #VU19368

Vulnerability risk: High

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-13917

CWE-ID: CWE-78

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Exim
Server applications / Mail servers

Vendor: Exim

Description

The vulnerability allows a remote attacker to execute arbitrary shell commands on the target system.

The vulnerability exists due to insufficient filtering of user-supplied data under certain conditions, e.g. if your configuration uses the ${sort } expansion. A remote unauthenticated attacker can send a specially crafted email, modify $local_part or $domain items, inject and execute arbitrary OS commands on the target system with root privileges.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system however requires non-default exim configuration.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Exim: 4.85 - 4.92

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External links
http://exim.org/static/doc/security/CVE-2019-13917.txt

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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.