Authentication bypass in Dovecot

1) Authentication bypass

EUVDB-ID: #VU17374

Risk: Medium

CVSSv3.1: 7.4 [CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2019-3814

CWE-ID: CWE-592 - Authentication Bypass Issues

Exploit availability: No

Description

The vulnerability allows a remote authenticated attacker to bypass authentication.

The weakness exists due to taking of the username from the user provided authentication fields (e.g. LOGIN command). A remote attacker with access to a valid trusted certificate without the ssl_cert_username_field in it can bypass password verification if the provided trusted SSL certificate is missing the username field and login as anyone else in the system

Mitigation

The vulnerability has been addressed in the versions 2.2.36.1, 2.3.4.1.

Vulnerable software versions

Dovecot: 1.1.0 - 2.3.4

External links

http://www.dovecot.org/list/dovecot/2019-February/114575.html

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

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.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.