Authentication bypass in dovecot (Alpine package)

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

Install update from vendor's website.

Vulnerable software versions

dovecot (Alpine package): 1.2.5-r0 - 2.2.34-r3

External links

http://git.alpinelinux.org/aports/commit/?id=5f25591dbfbb2c21341966e5e9dd125f98bd5aaa
http://git.alpinelinux.org/aports/commit/?id=b503ca5a2b74ae32b4eb510b4b98398f6909cb29
http://git.alpinelinux.org/aports/commit/?id=5725c3c222d375b3272cdc3c99476cc274e0ddc9
http://git.alpinelinux.org/aports/commit/?id=c98b313e7d98a22a3dd4c5c2e7f5bfe2d2415977
http://git.alpinelinux.org/aports/commit/?id=fd69630170f2a692179470d8d46927697bb4806d

Q & A

Can this vulnerability be exploited remotely?

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

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.