-- Corsaire Security Advisory -- Title: Sygate Secure Enterprise replay issue Date: 20.11.03 Application: Sygate Secure Enterprise prior to 3.5MR3 Environment: Windows NT, 2000, 2003 Author: Martin O'Neal [martin.oneal@corsaire.com] Audience: General distribution Reference: c031120-002 -- Scope -- The aim of this document is to clearly define an issue that exists with the Sygate Secure Enterprise (SSE) product [1] that will allow a remote attacker to exhaust resources on the server, potentially provoking a DoS condition. -- History -- Discovered: 20.11.03 (Martin O'Neal) Vendor notified: 14.01.04 Document released: 10.8.04 -- Overview -- The Sygate Secure Enterprise (SSE) [2] provides "the necessary features required to scale policy management across the world's largest enterprises, driving individual and appropriate policies for up to hundreds of thousands of users". Part of this functionality is providing centralised logging functionality to both the Sygate Enforcer and Sygate Security Agent (SSA) products. In practise, the SSE uses HTTP to communicate with the SSA clients. These exchanges do not implement any form of replay protection, so an attacker can simply send repeated requests until all the resources on the host are exhausted. -- Analysis -- The SSE product communicates with valid SSA clients via the HTTP protocol. These exchanges include a number of fields that are encrypted using a static key (that is common across all SSA clients). Some of these fields uniquely identify the SSA client instance, and others contain the actual data payload, such as log entries for centralised storage, or authentication sequences. As the key used to encrypt the data never changes, and the fields include no replay protection, all an attacker need do is to capture a valid protocol session, then replay it against the server repeatedly until the server exhausts all its resources. -- Recommendations -- The SSE product should be upgraded to a version that is not susceptible to this issue. -- Background -- This issue was discovered using a custom protocol analysis tool developed by Corsaire's security assessment team. This tool is not available publicly, but is an example of the specialist approach used by Corsaire's consultants as part of a commercial security assessment. To find out more about the cutting edge services provided by Corsaire simply visit our web site at http://www.corsaire.com -- CVE -- The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2004-0163 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardises names for security problems. -- References -- [1] http://www.sygate.com [2] http://www.sygate.com/products/enterprise_policy_management.htm -- Revision -- a. Initial release. b. Corrected grammatical errors. c. Minor revisions. -- Distribution -- This security advisory may be freely distributed, provided that it remains unaltered and in its original form. -- Disclaimer -- The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Corsaire accepts no responsibility for any damage caused by the use or misuse of this information. -- About Corsaire -- Corsaire are a leading information security consultancy, founded in 1997 in Guildford, Surrey, UK. Corsaire bring innovation, integrity and analytical rigour to every job, which means fast and dramatic security performance improvements. Our services centre on the delivery of information security planning, assessment, implementation, management and vulnerability research. A free guide to selecting a security assessment supplier is available at http://www.penetration-testing.com Copyright 2004 Corsaire Limited. All rights reserved.