OpenSSH certificate information disclosure

openssh-certificate-info-disclosure (65163) The risk level is classified as LowLow Risk

Description:

OpenSSH could allow a remote attacker to obtain sensitive information, caused by an uninitialized variable in the key_certify() function when generating legacy certificates. An attacker could exploit this vulnerability to obtain stack memory and other sensitive information.

*CVSS:

Base Score: 5
  Access Vector: Network
  Access Complexity: Low
  Authentication: None
  Confidentiality Impact: Partial
  Integrity Impact: None
  Availability Impact: None
 
Temporal Score: 3.7
  Exploitability: Unproven
  Remediation Level: Official-Fix
  Report Confidence: Confirmed

Consequences:

Obtain Information

Remedy:

Upgrade to the latest version of OpenSSH (5.8 or later), available from the OpenSSH Web site. See References.

For other distributions:
Apply the appropriate update for your system. See References.

References:

  • HP Security Bulletin HPSBMA02658 SSRT100413 rev.1: Insight Control for Linux (IC-Linux), Remote Unauthorized Elevation of Privilege, Execution of Arbitrary Code, Encryption Downgrade, Information Disclosure, Denial of Service (DoS).
  • OpenSSH Security Advisory: legacy-certs.adv: Legacy certificates generated by OpenSSH might contain data from the stack thus leaking confidential information.
  • OpenSSH Web Site: OpenSSH 5.8 has just been released.
  • BID-46155: OpenSSH Legacy Certificate Signing Information Disclosure Vulnerability
  • CVE-2011-0539: The key_certify function in usr.bin/ssh/key.c in OpenSSH 5.6 and 5.7, when generating legacy certificates using the -t command-line option in ssh-keygen, does not initialize the nonce field, which might allow remote attackers to obtain sensitive stack memory contents or make it easier to conduct hash collision attacks.
  • OSVDB ID: 70873: OpenSSH Legacy Certificates Stack Memory Disclosure
  • SA43181: OpenSSH Legacy Certificates Stack Memory Leak Weakness
  • SA44269: HP Insight Control for Linux Multiple Vulnerabilities
  • VUPEN/ADV-2011-0284: OpenSSH Legacy Certificate Signing Information Disclosure Vulnerability

Platforms Affected:

  • HP Insight Control For Linux 6.0
  • HP Insight Control For Linux 6.1
  • HP Insight Control For Linux 6.2
  • OpenBSD OpenSSH 5.6
  • OpenBSD OpenSSH 5.7

Reported:

Feb 03, 2011

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The information within this database may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. In no event shall IBM be held liable for any damages whatsoever arising out of or in connection with the use or spread of this information.

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