Authentication bypass in libvirt

1) Improper Authentication

EUVDB-ID: #VU33986

Risk: Medium

CVSSv4.0: 4.5 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2016-5008

CWE-ID: CWE-287 - Improper Authentication

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to an error in when processing authentication requests. libvirt before 2.0.0 improperly disables password checking when the password on a VNC server is set to an empty string, which allows remote attackers to bypass authentication and establish a VNC session by connecting to the server.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

libvirt: 1.1.0 - 1.3.5

CPE2.3

• cpe:2.3:a:libvirt_org:libvirt:1.1.0:*:*:*:*:*:*:*
• cpe:2.3:a:libvirt_org:libvirt:1.1.1:*:*:*:*:*:*:*
• cpe:2.3:a:libvirt_org:libvirt:1.1.2:*:*:*:*:*:*:*

External links

https://lists.opensuse.org/opensuse-updates/2016-07/msg00054.html
https://lists.opensuse.org/opensuse-updates/2016-07/msg00055.html
https://lists.opensuse.org/opensuse-updates/2016-08/msg00024.html
https://rhn.redhat.com/errata/RHSA-2016-2577.html
https://security.libvirt.org/2016/0001.html
https://www.debian.org/security/2016/dsa-3613
https://www.securityfocus.com/bid/91562
https://bugzilla.redhat.com/show_bug.cgi?id=1180092
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DZZMOMRXNPALA34XDF5NK363KDLAYSTL/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QTQF6LXKEEMJG4VOOCIAPJAD6ACBYP4W/
https://usn.ubuntu.com/3576-1/

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.