Privilege escalation in Postfix

1) Privilege escalation

EUVDB-ID: #VU7062

Risk: Low

CVSSv3.1: 3.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: N/A

CWE-ID: CWE-427 - Uncontrolled Search Path Element

Exploit availability: No

Description

The vulnerability allows a local user to escalate his privileges on the system.

The vulnerability exists due to Berkeley DB versions 2 and later try to read settings from a file DB_CONFIG in the current directory. A local user can create a specially crafted  DB_CONFIG file and escalate his privileges on the system with Postfix set-gid programs (postdrop, postqueue) before they chdir to the Postfix queue directory, and with the postmap and postalias commands depending on whether the user's current directory is writable by other users.

Successful exploitation of the vulnerability may allow a local user to gain elevated privileges on the system.

Mitigation

Update to version 3.2.2, 3.1.6, 3.0.10 or 2.11.10

Vulnerable software versions

Postfix: 2.11.0 - 3.2.1

CPE2.3

• cpe:2.3:a:postfix_org:postfix:2.11.8:*:*:*:*:*:*:*
• cpe:2.3:a:postfix_org:postfix:2.11.7:*:*:*:*:*:*:*
• cpe:2.3:a:postfix_org:postfix:2.11.6:*:*:*:*:*:*:*

External links

http://www.postfix.org/announcements/postfix-3.2.2.html

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

The attacker would have to login to the system and perform certain actions in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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