Open-Xchange Security Advisory 2021-01-04

Product: Dovecot
Vendor: OX Software GmbH
Internal reference: DOP-2009 (Bug ID)
Vulnerability type: CWE-150: Improper Neutralization of Escape, Meta, or
Control Sequences
Vulnerable version: 2.2.26-2.3.11.3
Vulnerable component: imap
Report confidence: Confirmed
Solution status: Fixed by Vendor
Fixed version: 2.3.13
Vendor notification: 2020-08-17
Solution date: 2020-08-27
Public disclosure: 2021-01-04
CVE reference: CVE-2020-24386
CVSS: 8.2 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N)

Vulnerability Details:

When imap hibernation is active, an attacker can cause Dovecot to
discover file
system directory structure and access other users' emails using
specially crafted
command. The attacker must have valid credentials to access the mail server.

Risk:

Attacker can access other users' emails and filesystem information.

Workaround:

Operators can choose to disable IMAP hibernation. IMAP hibernation is
not on by
default. To ensure imap hibernation is disabled, make sure
imap_hibernate_timeout
is set to 0 or unset.

Solution:

Operators should update to 2.3.13 or later version.