Input validation error in strongSwan

1) Input validation error

EUVDB-ID: #VU32362

Risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2015-8023

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote non-authenticated attacker to manipulate data.

The server implementation of the EAP-MSCHAPv2 protocol in the eap-mschapv2 plugin in strongSwan 4.2.12 through 5.x before 5.3.4 does not properly validate local state, which allows remote attackers to bypass authentication via an empty Success message in response to an initial Challenge message.

Mitigation

Install update from vendor's website.

Vulnerable software versions

strongSwan: 5.3.0 - 5.3.3

External links

http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00025.html
http://lists.opensuse.org/opensuse-updates/2015-11/msg00139.html
http://www.debian.org/security/2015/dsa-3398
http://www.securityfocus.com/bid/84947
http://www.ubuntu.com/usn/USN-2811-1
http://www.strongswan.org/blog/2015/11/16/strongswan-vulnerability-(cve-2015-8023).html

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.