Privilege escalation in Cyrus IMAP

1) Input validation error

EUVDB-ID: #VU23774

Risk: Medium

CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-19783

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote user to escalate privileges within the application.

The vulnerability exists due to insufficient validation of user-supplied input in autosieve_createfolder() function in imap/lmtp_sieve.c. A remote email user can create any mailbox with administrative privileges.

Successful exploitation of the vulnerability requires that the sieve script uploading is allowed (3.x) or certain non-default sieve options are enabled (2.x).

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Cyrus IMAP Server: 2.5.0 - 3.1.8

External links

http://www.cyrusimap.org/imap/download/release-notes/2.5/x/2.5.15.html
http://www.cyrusimap.org/imap/download/release-notes/3.0/x/3.0.13.html

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.