FreeBSD : OpenVPN -- out-of-bounds write in legacy key-method 1 (3dd6ccf4-a3c6-11e7-a52e-0800279f2ff8)

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


Synopsis :

The remote FreeBSD host is missing one or more security-related
updates.

Description :

Steffan Karger reports :

The bounds check in read_key() was performed after using the value,
instead of before. If 'key-method 1' is used, this allowed an attacker
to send a malformed packet to trigger a stack-based buffer overflow. [...]

Note that 'key-method 1' has been replaced by 'key method 2' as the
default in OpenVPN 2.0 (released on 2005-04-17), and explicitly
deprecated in 2.4 and marked for removal in 2.5. This should limit the
amount of users impacted by this issue.

See also :

https://community.openvpn.net/openvpn/wiki/CVE-2017-12166
http://www.nessus.org/u?69492f87
http://www.nessus.org/u?6b1e1802

Solution :

Update the affected packages.

Risk factor :

Medium / CVSS Base Score : 6.8
(CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P)

Family: FreeBSD Local Security Checks

Nessus Plugin ID: 103523 ()

Bugtraq ID:

CVE ID: CVE-2017-12166

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