FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

OpenVPN -- out-of-bounds write in legacy key-method 1

Affected packages
		openvpn-polarssl	<	2.3.18
2.4.0	<=	openvpn-mbedtls	<	2.4.4
2.4.0	<=	openvpn	<	2.4.4
		openvpn	<	2.3.18

Details

VuXML ID	3dd6ccf4-a3c6-11e7-a52e-0800279f2ff8
Discovery	2017-09-21
Entry	2017-09-27

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 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Note that 'key-method 1' has been replaced by 'key method 2' as the default in OpenVPN 2.0 (released on 2005-04-17), and explicitly deprecated in 2.4 and marked for removal in 2.5.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.

[source]

References

CVE Name	CVE-2017-12166
URL	https://community.openvpn.net/openvpn/wiki/CVE-2017-12166
URL	https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg15492.html