Vulnerability identifier: #VU43025

Vulnerability risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2011-4318

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Dovecot
Server applications / Mail servers

Vendor: Dovecot

Description

The vulnerability allows a remote non-authenticated attacker to read and manipulate data.

Dovecot 2.0.x before 2.0.16, when ssl or starttls is enabled and hostname is used to define the proxy destination, does not verify that the server hostname matches a domain name in the subject's Common Name (CN) of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via a valid certificate for a different hostname.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Dovecot: 2.0.0 - 2.0.15

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External links
http://hg.dovecot.org/dovecot-2.0/rev/5e9eaf63a6b1
http://rhn.redhat.com/errata/RHSA-2013-0520.html
http://secunia.com/advisories/46886
http://secunia.com/advisories/52311
http://www.dovecot.org/list/dovecot-news/2011-November/000200.html
http://www.openwall.com/lists/oss-security/2011/11/18/5
http://www.openwall.com/lists/oss-security/2011/11/18/7
http://bugs.gentoo.org/show_bug.cgi?id=390887
http://bugzilla.redhat.com/show_bug.cgi?id=754980

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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.