FreeBSD < 10.3-RELEASE-p21 / 11.0 < 11.0-RELEASE-p12 / 11.1 < 11.1-RELEASE-p1 OpenSSH Password Length DoS (FreeBSD-SA-17:06.openssh)

This script is Copyright (C) 2017 Tenable Network Security, Inc.


Synopsis :

The remote FreeBSD host is missing a security-related update.

Description :

The version of the FreeBSD kernel running on the remote host is prior
to 10.3-RELEASE-p21, 11.0 prior to 11.0-RELEASE-p12, or 11.1 prior to
11.1-RELEASE-p1. It, therefore, affected by a flaw in built-in
password authentication in OpenSSH. An unauthenticated, remote
attacker can exploit this issue by sending very long passwords when
PasswordAuthentication is enabled by the system administrator,
resulting in a denial of service condition.

Note that this issue only affects hosts with PasswordAuthentication
enabled in /etc/ssh/sshd_config (the default FreeBSD configuration).

You may workaround this issue by disabling PasswordAuthentication and
restarting sshd.

See also :

http://www.nessus.org/u?beaa28e9

Solution :

Upgrade to FreeBSD version 10.3-RELEASE-p21 / 11.0-RELEASE-p12 /
11.1-RELEASE-p1 or later. Alternatively, apply the workaround
referenced in the advisory to disable PasswordAuthentication.

Risk factor :

High / CVSS Base Score : 7.8
(CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C)

Family: FreeBSD Local Security Checks

Nessus Plugin ID: 102917 ()

Bugtraq ID: 92212

CVE ID: CVE-2016-6515

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