Multiple vulnerabilities in Dovecot

Published: 2020-02-13

Risk	High
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2020-7957 CVE-2020-7046
CWE-ID	CWE-20 CWE-835
Exploitation vector	Network
Public exploit	N/A
Vulnerable software Subscribe	Dovecot Server applications / Mail servers
Vendor	Dovecot

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Input validation error

EUVDB-ID: #VU25340

Risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-7957

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

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

The vulnerability exists due to insufficient validation of user-supplied input within the IMAP and LMTP components when many characters must be read while computing the snippet and a trailing ">" character is present. As a result the recipient cannot read all messages in the mailbox.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Dovecot: 2.3.9 - 2.3.9.2

External links

http://www.openwall.com/lists/oss-security/2020/02/12/2
http://dovecot.org/pipermail/dovecot-news/2020-February/000430.html
http://dovecot.org/security

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker 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.

2) Infinite loop

EUVDB-ID: #VU25339

Risk: High

CVSSv3.1: 7.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-7046

CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')