Information disclosure in libssh2

1) Information disclosure

EUVDB-ID: #VU33068

Risk: Medium

CVSSv3.1: 5.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2016-0787

CWE-ID: CWE-200 - Information exposure

Exploit availability: No

Description

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

The diffie_hellman_sha256 function in kex.c in libssh2 before 1.7.0 improperly truncates secrets to 128 or 256 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

libssh2: 1.0 - 1.6.0

External links

http://lists.fedoraproject.org/pipermail/package-announce/2016-February/177980.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-March/178573.html
http://lists.opensuse.org/opensuse-updates/2016-03/msg00008.html
http://www.debian.org/security/2016/dsa-3487
http://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html
http://www.securityfocus.com/bid/82514
http://bto.bluecoat.com/security-advisory/sa120
http://kc.mcafee.com/corporate/index?page=content&id=SB10156
http://puppet.com/security/cve/CVE-2016-0787
http://security.gentoo.org/glsa/201606-12
http://www.libssh2.org/adv_20160223.html
http://www.libssh2.org/CVE-2016-0787.patch

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.