<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE glsa SYSTEM "http://www.gentoo.org/dtd/glsa.dtd"> <glsa id="201606-12"> <title>libssh and libssh2: Multiple vulnerabilities</title> <synopsis>Multiple vulnerabilities have been found in libssh and libssh2, the worst of which allows remote attackers to cause Denial of Service. </synopsis> <product type="ebuild"/> <announced>2016-06-26</announced> <revised count="1">2016-06-26</revised> <bug>533366</bug> <bug>575474</bug> <bug>575484</bug> <access>remote</access> <affected> <package name="net-libs/libssh" auto="yes" arch="*"> <unaffected range="ge">0.7.3</unaffected> <vulnerable range="lt">0.7.3</vulnerable> </package> <package name="net-libs/libssh2" auto="yes" arch="*"> <unaffected range="ge">1.7.0</unaffected> <vulnerable range="lt">1.7.0</vulnerable> </package> </affected> <background> <p>libssh is a mulitplatform C library implementing the SSHv2 and SSHv1 protocol on client and server side. </p> </background> <description> <p>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. </p> <p>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. </p> </description> <impact type="normal"> <p>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. </p> </impact> <workaround> <p>There is no known workaround at this time.</p> </workaround> <resolution> <p>All libssh users should upgrade to the latest version:</p> <code> # emerge --sync # emerge --ask --oneshot --verbose ">=net-libs/libssh-0.7.3" </code> <p>All libssh2 users should upgrade to the latest version:</p> <code> # emerge --sync # emerge --ask --oneshot --verbose ">=net-libs/libssh2-1.7.0" </code> </resolution> <references> <uri link="https://nvd.nist.gov/nvd.cfm?cvename=CVE-2014-8132">CVE-2014-8132</uri> <uri link="https://nvd.nist.gov/nvd.cfm?cvename=CVE-2016-0739">CVE-2016-0739</uri> <uri link="https://nvd.nist.gov/nvd.cfm?cvename=CVE-2016-0787">CVE-2016-0787</uri> </references> <metadata tag="requester" timestamp="2015-06-30T22:23:55Z"> keytoaster </metadata> <metadata tag="submitter" timestamp="2016-06-26T12:56:59Z">b-man</metadata> </glsa>