Vulnerability identifier: #VU16153

Vulnerability risk: Low

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-2669

CWE-ID: CWE-400

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Dovecot
Server applications / Mail servers

Vendor: Dovecot

Description

The vulnerability allows a remote attacker to perform denial of service (DoS)M attack.

The vulnerability exists due to the username sent by the IMAP/POP3 client was sent through var_expand() to perform %variable expansion when 'dict' passdb and userdb were used for user authentication. A remote attacker can send specially crafted %variable fields, use excessive memory and cause the process to crash.

Mitigation
Update to version 2.2.29.

Vulnerable software versions

Dovecot: 2.2.0 - 2.2.28

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External links
http://dovecot.org/pipermail/dovecot-news/2017-April/000341.html

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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.