Summary

• A vulnerability in the ACS Report component of Cisco Secure Access Control System (ACS) could allow an unauthenticated, remote attacker to execute arbitrary commands on an affected system. Commands executed by the attacker are processed at the targeted user's privilege level.

  The vulnerability is due to insufficient validation of the Action Message Format (AMF) protocol. An attacker could exploit this vulnerability by sending a crafted AMF message that contains malicious code to a targeted user. A successful exploit could allow the attacker to execute arbitrary commands on the ACS device.

  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:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180502-acs1

Affected Products

• Vulnerable Products

  This vulnerability affects all releases of Cisco Secure ACS prior to Release 5.8 Patch 7. Administrators can use one of the following methods to determine which Cisco Secure ACS release is running on a device.

  Cisco Secure ACS CLI

  The show version command can be issued from the Cisco Secure ACS CLI. The following example shows the output of the show version command for a device that is running Cisco Secure ACS 5.8.0.32 with Cumulative Patch 1 installed:

  acs55/admin# show version
  
  Cisco Application Deployment Engine OS Release: 2.2
  ADE-OS Build Version: 2.2.2.013
  ADE-OS System Architecture: x86_64
  
  Copyright (c) 2005-2015 by Cisco Systems, Inc.
  All rights reserved.
  Hostname: acsx5
  
  
  Version information of installed applications
  ---------------------------------------------
  
  
  Cisco ACS VERSION INFORMATION
  -----------------------------
  Version : 5.8.0.32
  Internal Build ID : B.442
  Patches : 
  5-8-0-32-1
  
  acs55/admin#

  Cisco Secure ACS Web-Based Interface

  To determine which release of Cisco Secure ACS is running on a device, log in to the Cisco Secure ACS web-based interface and click the About link in the top right corner of the screen.

  Products Confirmed Not Vulnerable

  Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.

  Cisco has confirmed that the following Cisco Secure ACS products are not affected by this vulnerability:

  • Cisco Secure Access Control Server Express
  • Cisco Secure Access Control Server for Windows
  • Cisco Secure Access Control Server Solution Engine
  • Cisco Secure Access Control Server View

Details

• Cisco Secure ACS operates as a centralized RADIUS and TACACS+ server, combining user authentication, user and administrator device access control, and policy control into a centralized identity networking solution. Cisco Secure ACS provides central management of access policies for device administration and wireless, wired 802.1x, and remote VPN access scenarios. The identity stores can be internal or external. An internal identity store has user credential information stored in an internal database. With an external identity store, Cisco Secure ACS will retrieve information from an external database.

  Note: The Cisco Secure ACS product offering is no longer being sold after August 30, 2017. Customers may view the end-of-life notice.

Workarounds

• There are no workarounds that address this vulnerability.

Fixed Software

• Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
  https://www.cisco.com/c/en/us/products/end-user-license-agreement.html

  Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.

  When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, 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.

  Customers Without Service Contracts

  Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC:
  https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html

  Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.

  Fixed Releases

  This vulnerability is fixed in Cisco Secure ACS Release 5.8.0.32 with Cumulative Patch 7. The software can be downloaded from the Software Center on Cisco.com by clicking Browse All and navigating to Security > Network Visibility and Segmentation> Secure Access Control System > Secure Access Control System 5.8.

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.

Source

• Cisco would like to thank security researchers Mikhail Klyuchnikov and Yury Aleynov from Positive Technologies for finding and reporting this vulnerability.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180502-acs1

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2018-May-02

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