libssh publickey_from_privatekey() function denial of service

libssh-publickeyfromprivatekey-dos (81595) The risk level is classified as MediumMedium Risk

Description:

libssh is vulnerable to a denial of service, caused by a NULL pointer dereference error when processing "Client: Diffie-Hellman Key Exchange Init" packet. A remote attacker could exploit this vulnerability to cause the application to crash.

*CVSS:

Base Score: 5
  Access Vector: Network
  Access Complexity: Low
  Authentication: None
  Confidentiality Impact: None
  Integrity Impact: None
  Availability Impact: Partial
 
Temporal Score: 4.4
  Exploitability: High
  Remediation Level: Official-Fix
  Report Confidence: Confirmed

Consequences:

Denial of Service

Remedy:

Upgrade to the latest version of libssh (0.5.4 or later), available from the libssh Web site. See References.

References:

  • IBM Security Protection Advisory: libssh publickey_from_privatekey() function denial of service.
  • libssh Web Site: libssh.
  • Red Hat Bugzilla Bug 894407: CVE-2013-0176 libssh: NULL dereference leads to denial of service.
  • BID-57571: libssh CVE-2013-0176 Denial of Service Vulnerability
  • CVE-2013-0176: The publickey_from_privatekey function in libssh before 0.5.4, when no algorithm is matched during negotiations, allows remote attackers to cause a denial of service (NULL pointer dereference and crash) via a Client: Diffie-Hellman Key Exchange Init packet.

Platforms Affected:

  • libssh libssh 0.5.3

Reported:

Jan 22, 2013

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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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