Debian Security Advisory

DSA-3626-1 openssh -- security update

Date Reported:
24 Jul 2016
Affected Packages:
Security database references:
In the Debian bugtracking system: Bug 831902.
In Mitre's CVE dictionary: CVE-2016-6210.
More information:

Eddie Harari reported that the OpenSSH SSH daemon allows user enumeration through timing differences when trying to authenticate users. When sshd tries to authenticate a non-existing user, it will pick up a fixed fake password structure with a hash based on the Blowfish algorithm. If real users passwords are hashed using SHA256/SHA512, then a remote attacker can take advantage of this flaw by sending large passwords, receiving shorter response times from the server for non-existing users.

For the stable distribution (jessie), this problem has been fixed in version 1:6.7p1-5+deb8u3.

For the unstable distribution (sid), this problem has been fixed in version 1:7.2p2-6.

We recommend that you upgrade your openssh packages.