Gentoo: GLSA-201606-12: libssh and libssh2: Multiple vulnerabilities
Summary
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.
Resolution
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"
References
[ 1 ] CVE-2014-8132 http://nvd.nist.gov/nvd.cfm?cvename=CVE-2014-8132 [ 2 ] CVE-2016-0739 http://nvd.nist.gov/nvd.cfm?cvename=CVE-2016-0739 [ 3 ] CVE-2016-0787 http://nvd.nist.gov/nvd.cfm?cvename=CVE-2016-0787
Availability
This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:
https://security.gentoo.org/glsa/201606-12
Concerns
Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users' machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org.
Synopsis
Multiple vulnerabilities have been found in libssh and libssh2, the worst of which allows remote attackers to cause Denial of Service.
Background
libssh is a mulitplatform C library implementing the SSHv2 and SSHv1 protocol on client and server side.
Affected Packages
------------------------------------------------------------------- Package / Vulnerable / Unaffected ------------------------------------------------------------------- 1 net-libs/libssh < 0.7.3 >= 0.7.3 2 net-libs/libssh2 < 1.7.0 >= 1.7.0 ------------------------------------------------------------------- 2 affected packages
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.
