Trustwave SpiderLabs Security Advisory TWSL2014-005: VPN Privilege Escalation Vulnerability in Cisco ASA Published: 04/28/2014 Version: 2.0 Vendor: Cisco (http://www.cisco.com/) Product: Cisco ASA Version affected: 8.x, 9.x Product description: Cisco Adaptive Security Appliance (ASA) Software is the core operating system that powers the Cisco ASA family. It delivers enterprise-class firewall capabilities for ASA devices in an array of form factors - standalone appliances, blades, and virtual. ASA Software also integrates with other critical security technologies to deliver comprehensive solutions that meet continuously evolving security needs. Finding 1: Cisco ASA SSL VPN Privilege Escalation Vulnerability Credit: Jonathan Claudius of Trustwave SpiderLabs CVE: CVE-2014-2127 CWE: CWE-269 (Improper Privilege Management) Cisco ASA WebVPN (aka: clientless SSL VPN) suffers from a vulnerability that allows SSL VPN users (local or remote auth) to escalate privileges to level 15 access on the Firewall. When users are defined locally on a Cisco ASA, they can be done with the following options to prevent authorized access: username vpnuser password [REDACTED] encrypted username vpnuser attributes group-lock value RemoteAccessVPN service-type remote-access The first line defines the users name, password, and implicit privilege level (level 15). The remaining three lines define the users attributes. The first user attribute restricts the user to only the "RemoteAccessVPN" group. The second attribute restricts the user from performing management activities. However, when this user authenticates, they can perform a number of management functions just by simply hitting an ASDM-style URL path with a valid session SSL VPN session cookie. Examples of which include showing the full Cisco ASA configuration file (/admin/config), adding administrative users (/admin/exec/username+vuln2+password+vuln+privilege+15) or any other administrative function supported by ASDM. WebVPN and ASDM must be enabled for an attacker to exploit this vulnerability. Remediation Steps: Upgrade Cisco ASA firmware to 8.2(5.48), 8.3(2.40), 8.4(7.15), 8.6(1.13), 8.7(1.11), 9.0(4.1), 9.1(4.5) or the latest stable version. Revision History: 11/27/2013 - Vulnerability disclosed 11/27/2013 - Contacted vendor 11/27/2013 - Initial vendor response 04/09/2014 - Vendor released fix 04/09/2014 - Advisory published 04/28/2014 - PoC and References Added 04/28/2014 - Revision published Additional Credits: Laura Guay of Dell SecureWorks References 1. http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20140409-asa 2. https://github.com/rapid7/metasploit-framework/pull/3305 3. https://speakerdeck.com/claudijd/crowdsourcing-your-cisco-firewall-administration-dot-dot-dot-wat 4. https://vimeo.com/93010946 About Trustwave: Trustwave is the leading provider of on-demand and subscription-based information security and payment card industry compliance management solutions to businesses and government entities throughout the world. For organizations faced with today's challenging data security and compliance environment, Trustwave provides a unique approach with comprehensive solutions that include its flagship TrustKeeper compliance management software and other proprietary security solutions. Trustwave has helped thousands of organizations--ranging from Fortune 500 businesses and large financial institutions to small and medium-sized retailers--manage compliance and secure their network infrastructure, data communications and critical information assets. Trustwave is headquartered in Chicago with offices throughout North America, South America, Europe, Africa, China and Australia. For more information, visit https://www.trustwave.com About Trustwave SpiderLabs: SpiderLabs(R) is the advanced security team at Trustwave focused on application security, incident response, penetration testing, physical security and security research. The team has performed over a thousand incident investigations, thousands of penetration tests and hundreds of application security tests globally. In addition, the SpiderLabs Research team provides intelligence through bleeding-edge research and proof of concept tool development to enhance Trustwave's products and services. https://www.trustwave.com/spiderlabs Disclaimer: The information provided in this advisory is provided "as is" without warranty of any kind. Trustwave disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Trustwave or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Trustwave or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.