Summary

• The Cisco Intrusion Prevention System (IPS) Software has a vulnerability within the SSL/TLS subsystem utilized by the web management interface which could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
  
  Cisco has released software updates that address this vulnerability. This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20150311-ips

Affected Products

• Vulnerable Products

  Cisco IPS devices running version 7.2(1)E4 or later. This includes the following hardware:
  

  • IPS 4345
  • IPS 4345-DC
  • IPS 4360
  • IPS 4510
  • IPS 4520
  • IPS 4520-XL
  • ASA 5512-X IPS SSP
  • ASA 5515-X IPS SSP
  • ASA 5525-X IPS SSP
  • ASA 5545-X IPS SSP
  • ASA 5555-X IPS SSP
  • ASA 5585-X IPS SSP-10
  • ASA 5585-X IPS SSP-20
  • ASA 5585-X IPS SSP-40
  • ASA 5585-X IPS SSP-60

  How to Determine the Running Software Version

  To determine whether a vulnerable version of Cisco IPS Software is running on an appliance, administrators can issue the show version command. The following example shows a Cisco IPS 4345 that is running software version 7.1(3)E4:

  sensor# show version
  Application Partition:
  
  Cisco Intrusion Prevention System, Version 7.1(3)E4
  
  Host:
      Realm Keys          key1.0
  Signature Definition:
      Signature Update    S605.0        2011-10-25
  OS Version:             2.6.29.1
  Platform:               IPS-4345-K9

  Customers who use Cisco Intrusion Prevention System Device Manager (IDM) to manage devices can locate the software version in the table that is displayed in the login window or top left corner of the Cisco IDM window.

  Products Confirmed Not Vulnerable

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

Details

• A vulnerability within the SSL/TLS subsystem utilized by the web management interface of Cisco Intrusion Prevention System (IPS) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
  
  The vulnerability is due to a potential race condition when handling multiple HTTPS requests on the management interface. An attacker could exploit this vulnerability by negotiating a number of HTTPS connections with the management interface. An exploit could allow the attacker to make the MainApp process unresponsive. This creates a DoS condition because the Cisco IPS sensor is not able to execute several critical tasks including alert notification, event store management, and sensor authentication. The Cisco IPS web server is also unavailable while the MainApp process is unresponsive.
  
  Additionally, due to this general system failure, other processes such as the Analysis Engine may not work properly. The Cisco IPS may not continue to process traffic because the Analysis Engine process may not work properly. If the Cisco IPS is configured in promiscuous mode, mitigation actions that require MainApp processing such as the request-block-host or request-rate-limit event-actions may be unavailable. If the Cisco IPS is configured in inline mode, the sensor may not correctly perform inspection and mitigation actions, and may drop packets transiting the affected device. The condition persists until the device has been restarted.
  
  The vulnerability can be triggered only by SSL/TLS traffic directed to the TCP port and IP address of the management interface associated with the web server. The default TCP port is 443. Packets transiting an affected device through the sensing interfaces cannot be used to trigger this vulnerability.
  
  This vulnerability is documented in CSCuq40652 (registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2015-0654
  
  To recover from the DoS condition, find and block the attacking device then reload from a console command line.
  
  As a best practice Cisco recommends maintaining the IPS management access list, carefully allowing only trusted hosts to access the management interface of the IPS device. Blocking access using the access list can prevent a successful attack.

Workarounds

• There is no workaround for this vulnerability.
  

Fixed Software

• When considering software upgrades, customers are advised to consult the Cisco Security Advisories, Responses, and Notices 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 be upgraded 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.
  
  Cisco has released Cisco Intrusion Prevention System (IPS) Software version 7.3(3)E4 to remediate the vulnerability described in this document.
  
  Software Download
  Cisco IPS Software can be downloaded from the Software Center on Cisco.com by visiting http://www.cisco.com/cisco/software/navigator.html
  

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

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20150311-ips

Revision History

• Revision 1.0

  2015-March-11

  Initial public release.

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