OS Command Injection in exim (Alpine package)

1) OS Command Injection

EUVDB-ID: #VU18686

Risk: High

CVSSv3.1: 9.1 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C]

CVE-ID: CVE-2019-10149

CWE-ID: CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Exploit availability: Yes

Description

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

The vulnerability exists due to insufficient validation of email address within the deliver_message() function in /src/deliver.c. A remote unauthenticated attacker can send an email containing a specially crafted email address and execute arbitrary OS commands on the target system via execv() call with superuser privileges.

This vulnerability can be also exploited by authenticated local users to escalate privileges on the system.

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

Mitigation

Install update from vendor's website.

Vulnerable software versions

exim (Alpine package): 4.89.1-r0 - 4.91-r1

External links

http://git.alpinelinux.org/aports/commit/?id=3d8ae8e8d508872200529d643aab4684370ab1de
http://git.alpinelinux.org/aports/commit/?id=10f6d6b57c1bc6978981bb5bba137cf9e32d1a79
http://git.alpinelinux.org/aports/commit/?id=cb34e53649ad688804bbd0cf2707f90ad2533511
http://git.alpinelinux.org/aports/commit/?id=6212920763e5e59a83b6d2654a92e258ab791ea0
http://git.alpinelinux.org/aports/commit/?id=65097c9cdc4dc822b2fd204057a17312ed7a6b06

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. However, a fully functional exploit for this vulnerability is available.