OS Command Injection in exim (Alpine package)

1) OS Command Injection

EUVDB-ID: #VU19368

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 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Exploit availability: No

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 update from vendor's website.

Vulnerable software versions

exim (Alpine package): 4.86.2-r0 - 4.92-r1

CPE2.3

• cpe:2.3:o:alpine:exim_alpine_package:4.90.1-r1:*:*:*:*:alpine_linux:*:
• cpe:2.3:o:alpine:exim_alpine_package:4.92-r0:*:*:*:*:alpine_linux:*:
• cpe:2.3:o:alpine:exim_alpine_package:4.89.1-r0:*:*:*:*:alpine_linux:*:

External links

http://git.alpinelinux.org/aports/commit/?id=10f6d6b57c1bc6978981bb5bba137cf9e32d1a79
http://git.alpinelinux.org/aports/commit/?id=4e307ad47d11f989e230d577f19c1dab3286a9e9
http://git.alpinelinux.org/aports/commit/?id=cb34e53649ad688804bbd0cf2707f90ad2533511

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.