GLSA-201606-12 : libssh and libssh2: Multiple vulnerabilities

Medium Nessus Plugin ID 91843


The remote Gentoo host is missing one or more security-related patches.


The remote host is affected by the vulnerability described in GLSA-201606-12 (libssh and libssh2: Multiple vulnerabilities)

libssh and libssh2 both have a bits/bytes confusion bug and generate an abnormaly short ephemeral secret for the diffie-hellman-group1 and diffie-hellman-group14 key exchange methods. The resulting secret is 128 bits long, instead of the recommended sizes of 1024 and 2048 bits respectively.
Additionally, a double free on dangling pointers in initial key exchange packets within libssh could leave dangling pointers in the session crypto structures. It is possible to send a malicious kexinit package to eventually cause a server to do a double-free before this fix. This could be used for a Denial of Service attack.
Impact :

Remote attackers may gain access to confidential information due to the short keysize generated by libssh and libssh2, or cause a Denial of Service condition.
Workaround :

There is no known workaround at this time.


All libssh users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose '>=net-libs/libssh-0.7.3' All libssh2 users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose '>=net-libs/libssh2-1.7.0'

See Also

Plugin Details

Severity: Medium

ID: 91843

File Name: gentoo_GLSA-201606-12.nasl

Version: Revision: 2.2

Type: local

Published: 2016/06/27

Updated: 2016/10/10

Dependencies: 12634

Risk Information

Risk Factor: Medium

CVSS v2.0

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS v3.0

Base Score: 5.9

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Vulnerability Information

CPE: p-cpe:/a:gentoo:linux:libssh, p-cpe:/a:gentoo:linux:libssh2, cpe:/o:gentoo:linux

Required KB Items: Host/local_checks_enabled, Host/Gentoo/release, Host/Gentoo/qpkg-list

Patch Publication Date: 2016/06/26

Reference Information

CVE: CVE-2014-8132, CVE-2016-0739, CVE-2016-0787

GLSA: 201606-12