Denial of service in Cyrus IMAP

1) Input validation error

EUVDB-ID: #VU59879

Risk: Medium

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-2021-33582

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

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

The vulnerability exists due to insufficient validation of user-supplied input that is mishandled during hash-table interaction. A remote attacker can cause a denial of service (multiple-minute daemon hang) via input that is mishandled during hash-table interaction. Because there are many insertions into a single bucket, strcmp becomes slow.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Cyrus IMAP Server: 3.0.0 - 3.4.1

External links

http://www.cyrusimap.org/imap/download/release-notes/index.html
http://github.com/cyrusimap/cyrus-imapd/commits/master
http://cyrus.topicbox.com/groups/announce/T3dde0a2352462975-M1386fc44adf967e072f8df13/cyrus-imap-3-4-2-3-2-8-and-3-0-16-released
http://github.com/cyrusimap/cyrus-imapd/security/advisories

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.