NULL pointer dereference in dovecot (Alpine package)

1) NULL pointer dereference

EUVDB-ID: #VU27981

Risk: Medium

CVSSv3.1: 5.9 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2020-10957

CWE-ID: CWE-476 - NULL Pointer Dereference

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 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``

Mitigation

Install update from vendor's website.

Vulnerable software versions

dovecot (Alpine package): 2.3.2.1-r0 - 2.3.10-r0

External links

http://git.alpinelinux.org/aports/commit/?id=4188e3f4c8c70ca30f481278b85d52799ade266a
http://git.alpinelinux.org/aports/commit/?id=63c2cc277e73718a89df156cafffdaaf5bbad6cc
http://git.alpinelinux.org/aports/commit/?id=e9ada9531d3f3e60456ec07437a2f39f9a196861
http://git.alpinelinux.org/aports/commit/?id=25fe34656b9e14d6e4e67944f178c6687c95c901
http://git.alpinelinux.org/aports/commit/?id=2b1449bb52bbd408ea452e0f29312761f669c517

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. However, proof of concept for this vulnerability is available.