Corsaire Security Advisory - Sygate Secure Enterprise replay issue

– 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 [[email protected]]
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.