Cisco Unified Computing System 6200 Series Fabric Interconnect Series Switch DoS Vulnerability

Summary

• A vulnerability in the SSH management interface of the Cisco Unified Computing System (UCS) 6200 Series Fabric Interconnect Series Switch could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition because a fabric interconnect interface might not boot completely up or might have high CPU utilization. This would only happen if the attack occurred while a reload of the affected UCS switch was already in progress.
  
  The vulnerability is due to a lack of rate-limiting on incoming TCP connection requests for SSH, which is TCP port 22 during boot time. An attacker could exploit this vulnerability by sending a TCP SYN flood of packets to the SSH management interface of the device while a reload of the switch is in progress. An exploit could allow the attacker to create a DoS condition due to the Cisco UCS FI not proper properly booting up or having high CPU utilization.
  
  Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
  
  This advisory is available at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151210-ucs

Affected Products

• Vulnerable Products

  Cisco Unified Computing System release 2.2(3f)A is vulnerable.

  Products Confirmed Not Vulnerable

  No other Cisco products are currently known to be affected by this vulnerability.

Workarounds

• Cisco recommends that the Cisco UCS FI SSH management interface is behind a firewall and not directly reachable via the Internet.

Fixed Software

• When considering software upgrades, customers are advised to consult the Cisco Security Advisories and Responses archive at http://www.cisco.com/go/psirt and review subsequent advisories to determine exposure and a complete upgrade solution.
  
  In all cases, customers should ensure that the devices to upgrade contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
  
  

Exploitation and Public Announcements

• The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
  

URL

• http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151210-ucs

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release	-	Final	2015-December-10

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