SB2020022510 - Multiple vulnerabilities in OpenSMTPD

Description

This security bulletin contains information about 2 secuirty vulnerabilities.

1) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2020-8793)

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to the application does not drop privileges when executing the "/usr/sbin/smtpctl" application with  a "-bi" command-line argument. A local user can leverage this behavior and use a specially crafted hardlink to execute arbitrary code on the system with elevated privileges.

2) Out-of-bounds read (CVE-ID: CVE-2020-8794)

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.

Remediation

Install update from vendor's website.

References

• http://seclists.org/oss-sec/2020/q1/86
• https://ftp.openbsd.org/pub/OpenBSD/patches/6.6/common/021_smtpd_envelope.patch.sig
• https://www.openbsd.org/security.html
• https://www.openwall.com/lists/oss-security/2020/02/24/5