Vulnerability identifier: #VU27984

Vulnerability risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2020-10967

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Dovecot
Server applications / Mail servers

Vendor: Dovecot

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 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>``.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Dovecot: 2.3.0 - 2.3.10

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External links
http://seclists.org/oss-sec/2020/q2/122
http://dovecot.org/pipermail/dovecot-news/2020-May/000438.html

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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.