SB2020051820 - Ubuntu update for Dovecot

Description

This security bulletin contains information about 3 secuirty vulnerabilities.

1) NULL pointer dereference (CVE-ID: CVE-2020-10957)

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 when processing NOOP command. A remote attacker can send a specially crafted NOOP command to submission, submission-login or lmtp service, trigger a NULL pointer dereference and perform a denial of service attack.

PoC command:

``NOOP EE"FY``

2) Input validation error (CVE-ID: CVE-2020-10967)

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 passed via email message. A remote attacker can send a specially crafted email with empty quoted localpart and crash the submission or lmtp service.

PoC:

Send mail with envelope sender or recipient as ``<""@example.org>``.

3) Use-after-free (CVE-ID: CVE-2020-10958)

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

The vulnerability exists due to a use-after-free error when processing newline characters. A remote attacker can a specially crafted command to submission, submission-login or lmtp service and perform a denial of service (DoS) attack.

Remediation

Install update from vendor's website.

References

• https://usn.ubuntu.com/4361-1/