OpenSSH does not properly drop privileges when the UseLogin option is enabled, which allows local users to execute arbitrary commands by providing the command to the ssh daemon.

OpenSSH 5.6 and earlier, when J-PAKE is enabled, does not properly validate the public parameters in the J-PAKE protocol, which allows remote attackers to bypass the need for knowledge of the shared secret, and successfully authenticate, by sending crafted values in each round of the protocol, a related issue to CVE-2010-4252.

OpenSSH 4.4 was released and mentions:

Fix an unsafe signal hander reported by Mark Dowd. The signal handler was vulnerable to a race condition that could be exploited to perform a pre-authentication denial of service. On portable OpenSSH, this vulnerability could theoretically lead to pre-authentication remote code execution if GSSAPI authentication is enabled, but the likelihood of successful exploitation appears remote.

This could only affect RHEL4 as previous RHEL did not support GSSAPI

sshd in OpenSSH before 4.4, when using the version 1 SSH protocol, allows remote attackers to cause a denial of service (CPU consumption) via an SSH packet that contains duplicate blocks, which is not properly handled by the CRC compensation attack detector.

sshd in OpenSSH 3.6.1p2 and earlier, when PermitRootLogin is disabled and using PAM keyboard-interactive authentication, does not insert a delay after a root login attempt with the correct password, which makes it easier for remote attackers to use timing differences to determine if the password step of a multi-step authentication is successful, a different vulnerability than CVE-2003-0190.

A denial of service flaw was found in the way default server configuration of OpenSSH, a open source implementation of SSH protocol versions 1 and 2, performed management of its connection slot. A remote attacker could use this flaw to cause connection slot exhaustion on the server.

References: [1] http://seclists.org/oss-sec/2012/q1/1 [2] http://www.openwall.com/lists/oss-security/2013/02/06/5 [3] http://www.openwall.com/lists/oss-security/2013/02/07/3

Relevant upstream patches: [4] http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/servconf.c?r1=1.234#rev1.234 [5] http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshdconfig.5?r1=1.156#rev1.156 [6] http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshdconfig?r1=1.89#rev1.89

The authparseoptions function in auth-options.c in sshd in OpenSSH before 5.7 provides debug messages containing authorizedkeys command options, which allows remote authenticated users to obtain potentially sensitive information by reading these messages, as demonstrated by the shared user account required by Gitolite. NOTE: this can cross privilege boundaries because a user account may intentionally have no shell or filesystem access, and therefore may have no supported way to read an authorizedkeys file in its own home directory.

A security flaw was found in the way ssh-keysign, a ssh helper program for host based authentication, attempted to retrieve enough entropy information on configurations that lacked a built-in entropy pool in OpenSSL (a ssh-rand-helper program would be executed to retrieve the entropy from the system environment). A local attacker could use this flaw to obtain unauthorized access to host keys via ptrace(2) process trace attached to the 'ssh-rand-helper' program.

References: [1] http://www.openssh.com/txt/release-5.8p2 [2] http://www.openssh.com/txt/portable-keysign-rand-helper.adv [3] http://www.nessus.org/plugins/index.php?view=single&id=53841 [4] http://www.openwall.com/lists/oss-security/2011/11/21/11 (CVE assignment)

The default configuration of SSH allows X forwarding, which could allow a remote attacker to control a client's X sessions via a malicious xauth program.

Directory traversal vulnerability in scp in sshd 1.2.xx allows a remote malicious scp server to overwrite arbitrary files via a .. (dot dot) attack.

Unspecified vulnerability in portable OpenSSH before 4.4, when running on some platforms, allows remote attackers to determine the validity of usernames via unknown vectors involving a GSSAPI "authentication abort."

OpenSSH 4.6 and earlier, when ChallengeResponseAuthentication is enabled, allows remote attackers to determine the existence of user accounts by attempting to authenticate via S/KEY, which displays a different response if the user account exists, a similar issue to CVE-2001-1483.

The SSH protocol server sshd allows local users without shell access to redirect a TCP connection through a service that uses the standard system password database for authentication, such as POP or FTP.

The (1) remoteglob function in sftp-glob.c and the (2) processput function in sftp.c in OpenSSH 5.8 and earlier, as used in FreeBSD 7.3 and 8.1, NetBSD 5.0.2, OpenBSD 4.7, and other products, allow remote authenticated users to cause a denial of service (CPU and memory consumption) via crafted glob expressions that do not match any pathnames, as demonstrated by glob expressions in SSHFXPSTAT requests to an sftp daemon, a different vulnerability than CVE-2010-2632.