Vulnerability identifier: #VU25625

Vulnerability risk: Medium

CVSSv3.1: 6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:F/RL:O/RC:C]

CVE-ID: CVE-2020-8794

CWE-ID: CWE-125

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
OpenSMTPD
Server applications / Mail servers

Vendor: OpenBSD

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to a boundary condition in mta_io() function in mta_session.c for multi-line replies during mail delivery. A remote attacker can use a mail server to send specially crafted replies, trigger out-of-bounds read error and read contents of memory on the system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

OpenSMTPD: 6.6.0 - 6.6.3p1

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External links
http://www.openbsd.org/security.html
http://www.openwall.com/lists/oss-security/2020/02/24/5

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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, a fully functional exploit for this vulnerability is available.