OpenSSH ChallengeResponseAuthentication information disclosure

openssh-challenge-information-disclosure (33794) The risk level is classified as LowLow Risk

Description:

OpenSSH could allow a remote attacker to obtain sensitive information, caused by improper handling of error messages from failed login attempts. If ChallengeResponseAuthentication is enabled, a remote attacker could exploit this vulnerability to enumerate system accounts and obtain sensitive information.

Note: This vulnerability could also affect applications using OpenSSH.

Platforms Affected:

  • OpenBSD, OpenSSH 1.2
  • OpenBSD, OpenSSH 1.2.1
  • OpenBSD, OpenSSH 1.2.2
  • OpenBSD, OpenSSH 1.2.27
  • OpenBSD, OpenSSH 1.2.3
  • OpenBSD, OpenSSH 2.1
  • OpenBSD, OpenSSH 2.1.1
  • OpenBSD, OpenSSH 2.1.1p4
  • OpenBSD, OpenSSH 2.2
  • OpenBSD, OpenSSH 2.2.0p1
  • OpenBSD, OpenSSH 2.3
  • OpenBSD, OpenSSH 2.3.0p1
  • OpenBSD, OpenSSH 2.5
  • OpenBSD, OpenSSH 2.5.1
  • OpenBSD, OpenSSH 2.5.1p1
  • OpenBSD, OpenSSH 2.5.1p2
  • OpenBSD, OpenSSH 2.5.2
  • OpenBSD, OpenSSH 2.5.2p1
  • OpenBSD, OpenSSH 2.5.2p2
  • OpenBSD, OpenSSH 2.9
  • OpenBSD, OpenSSH 2.9.9
  • OpenBSD, OpenSSH 2.9.9p1
  • OpenBSD, OpenSSH 2.9.9p2
  • OpenBSD, OpenSSH 2.9p1
  • OpenBSD, OpenSSH 2.9p2
  • OpenBSD, OpenSSH 3.0
  • OpenBSD, OpenSSH 3.0.1
  • OpenBSD, OpenSSH 3.0.1p1
  • OpenBSD, OpenSSH 3.0.2
  • OpenBSD, OpenSSH 3.0.2p1
  • OpenBSD, OpenSSH 3.0p1
  • OpenBSD, OpenSSH 3.1
  • OpenBSD, OpenSSH 3.1p1
  • OpenBSD, OpenSSH 3.2
  • OpenBSD, OpenSSH 3.2.2
  • OpenBSD, OpenSSH 3.2.2p1
  • OpenBSD, OpenSSH 3.2.3
  • OpenBSD, OpenSSH 3.2.3p1
  • OpenBSD, OpenSSH 3.3
  • OpenBSD, OpenSSH 3.3p1
  • OpenBSD, OpenSSH 3.4
  • OpenBSD, OpenSSH 3.4p1
  • OpenBSD, OpenSSH 3.5
  • OpenBSD, OpenSSH 3.5p1
  • OpenBSD, OpenSSH 3.6
  • OpenBSD, OpenSSH 3.6.1
  • OpenBSD, OpenSSH 3.6.1p1
  • OpenBSD, OpenSSH 3.6.1p2
  • OpenBSD, OpenSSH 3.7
  • OpenBSD, OpenSSH 3.7.1
  • OpenBSD, OpenSSH 3.7.1p1
  • OpenBSD, OpenSSH 3.7.1p2
  • OpenBSD, OpenSSH 3.8
  • OpenBSD, OpenSSH 3.8.1
  • OpenBSD, OpenSSH 3.8.1p1
  • OpenBSD, OpenSSH 3.9
  • OpenBSD, OpenSSH 3.9.1
  • OpenBSD, OpenSSH 3.9.1p1
  • OpenBSD, OpenSSH 4.0
  • OpenBSD, OpenSSH 4.0p1
  • OpenBSD, OpenSSH 4.1p1
  • OpenBSD, OpenSSH 4.2
  • OpenBSD, OpenSSH 4.2p1
  • OpenBSD, OpenSSH 4.3
  • OpenBSD, OpenSSH 4.3p1
  • OpenBSD, OpenSSH 4.3p2
  • OpenBSD, OpenSSH 4.4
  • OpenBSD, OpenSSH 4.4p1
  • OpenBSD, OpenSSH 4.5
  • OpenBSD, OpenSSH 4.5p1
  • OpenBSD, OpenSSH 4.6

Remedy:

No remedy available as of November 29, 2008.

Consequences:

Obtain Information

References:

  • Full-Disclosure Mailing List, Fri Apr 20 2007 - 19:27:17 CDT, OpenSSH - System Account Enumeration if S/Key is used at http://archives.neohapsis.com/archives/fulldisclosure/2007-04/0590.html.
  • OpenSSH Web site, OpenSSH at http://openssh.com/.
  • BID-23601: OpenSSH S/Key Remote Information Disclosure Vulnerability
  • CVE-2007-2243: 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.
  • OSVDB ID: 34600: OpenSSH S/KEY Authentication Account Enumeration

Reported:

Apr 21, 2007

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