Information disclosure in libssh

1) Information disclosure

EUVDB-ID: #VU32329

Risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2016-0739

CWE-ID: CWE-200 - Exposure of sensitive information to an unauthorized actor

Exploit availability: No

Description

The vulnerability allows a remote non-authenticated attacker to gain access to sensitive information.

libssh before 0.7.3 improperly truncates ephemeral secrets generated for the (1) diffie-hellman-group1 and (2) diffie-hellman-group14 key exchange methods to 128 bits, which makes it easier for man-in-the-middle attackers to decrypt or intercept SSH sessions via unspecified vectors, aka a "bits/bytes confusion bug."

Mitigation

Install update from vendor's website.

Vulnerable software versions

libssh: 0.7.0 - 0.7.2

CPE2.3

• cpe:2.3:a:libssh:libssh:0.7.0:*:*:*:*:*:*:*
• cpe:2.3:a:libssh:libssh:0.7.1:*:*:*:*:*:*:*
• cpe:2.3:a:libssh:libssh:0.7.2:*:*:*:*:*:*:*

External links

https://lists.fedoraproject.org/pipermail/package-announce/2016-February/178058.html
https://lists.fedoraproject.org/pipermail/package-announce/2016-March/178822.html
https://lists.opensuse.org/opensuse-updates/2016-03/msg00111.html
https://rhn.redhat.com/errata/RHSA-2016-0566.html
https://www.debian.org/security/2016/dsa-3488
https://www.ubuntu.com/usn/USN-2912-1
https://puppet.com/security/cve/CVE-2016-0739
https://security.gentoo.org/glsa/201606-12
https://www.libssh.org/2016/02/23/libssh-0-7-3-security-and-bugfix-release/
https://www.libssh.org/security/advisories/CVE-2016-0739.txt

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.