Subject: [ASA-202001-6] opensmtpd: arbitrary command execution

Arch Linux Security Advisory ASA-202001-6
=========================================

Severity: Critical
Date    : 2020-01-29
CVE-ID  : CVE-2020-7247
Package : opensmtpd
Type    : arbitrary command execution
Remote  : Yes
Link    : https://security.archlinux.org/AVG-1090

Summary
=======

The package opensmtpd before version 6.6.2p1-1 is vulnerable to
arbitrary command execution.

Resolution
==========

Upgrade to 6.6.2p1-1.

# pacman -Syu "opensmtpd>=6.6.2p1-1"

The problem has been fixed upstream in version 6.6.2p1.

Workaround
==========

None.

Description
===========

smtp_mailaddr in smtp_session.c in OpenSMTPD 6.6, as used in OpenBSD
6.6 and other products, allows remote attackers to execute arbitrary
commands as root via a crafted SMTP session, as demonstrated by shell
metacharacters in a MAIL FROM field. This affects the "uncommented"
default configuration. The issue exists because of an incorrect return
value upon failure of input validation.

Impact
======

A remote attacker is able to execute arbitrary commands as root on the
affected host.

References
==========

https://www.openwall.com/lists/oss-security/2020/01/28/3
https://github.com/OpenSMTPD/OpenSMTPD/commit/d2688c097e0ff53037c7403e09426771876a3907
https://github.com/openbsd/src/commit/9dcfda045474d8903224d175907bfc29761dcb45
https://security.archlinux.org/CVE-2020-7247