Application protection

Teros Secure Application Gateway is an application-layer firewall that examines standard Web server traffic for security violations, such as hacker attacks or unauthorized data leaks, and stops them.

Teros Gateway, developed by Teros, digs deep. In contrast to a Layer 3 or 4 firewall that may only identify problems in the primitive transport layers of the IP stack, Teros Gateway will dissect outgoing and incoming packets to examine compliance with security policies. Although a firewall may detect anomalies such as a port scan or other reconnaissance attempts, the Teros Gateway learns your critical applications' normal behavior. Based on that information, it can block any deviant behavior.

Teros Gateway is a complex device with too many features for us to test each one. But, of course, that didn't stop us from blasting it with as many penetration attempts as we could.

Device description

The Teros 100 appliance is a 1U rack-mount unit with a red, plastic faceplate. A testament to simplicity, the device's front has four Category 5 cable plugs and a few lights. Usually, Gateway would be installed between the firewall and the Web servers, and that is where we placed it on our test local-area network.

Our Teros appliance had only one power supply, but the company offers a model with a redundant power supply that is hot-swappable. Teros Gateway runs on a hardened Linux operating system.

Initial installation

Installation starts with a command-line interface, which is used to set three IP address ranges for the appliance -- LAN, wide-area network and Control addresses -- and designate which appliance will serve as the management server. The instructions for this are several pages long, but the device comes with a laminated cheat-sheet. The commands may appear daunting at first, but we found the command usage was similar to that of a Cisco Systems router or switch.

The installation instructions left a bit to be desired. Nonetheless, any network professional will have no problem configuring this device.

Setup

After the initial installation, we summoned the management server's IP address from our Web browser and logged in to the Web interface via an encrypted connection. After another log-in with another set of credentials, we were presented with a rich Web application.

The management interface was responsive and easy to use. We logged in via a virtual private network-encrypted broadband connection several times to manage the device, and every time the interface was as responsive as if we were in the same room with the unit.

This management graphical user interface (GUI) runs in a pop-up window, so be sure to turn off your pop-up blocker. We went to the Properties function of Internet Explorer and set Teros Gateway as a trusted Web site.

Any junior-level administrator will have no problem mastering the management GUI in a few hours because it is easy to use. The interface is organized into a few simple categories including Overview, Setup, Dashboard and Reports.

Our tests

Because our attacks were quite serious, we used two Web servers with two concept Web applications instead of using production servers. We chose WebGoat from the Open Web Security Application Project (www.owasp.org/software/Webgoat.html) as one of our applications because of its usefulness in demonstrating a variety ofvulnerabilities.

First, we set up our Web application servers and performed various HTTP attacks with Teros Gateway disabled. We used a variety of attack methods, including automated attacks from a Nessus security scanner.

Second, we enabled Teros Gateway and reran the same tests.

We repeated this process on both applications. The results showed that Teros Gateway effectively protected our Web servers. We found that all the HTTP vulnerabilities detected and warnings shown by our instruments during the initial tests were absent after Teros Gateway was enabled.

We were particularly impressed that these results were achieved after we had allowed Teros Gateway only a short time to learn our applications' normal traffic patterns. Once it has had a couple of weeks to learn normal application requests, its filter rules should become even more sensitive and accurate.

Teros Gateway's protective features surpassed our ability to exercise its complete functionality, even with sophisticated tools at our disposal.

Device security

As part of our typical test procedures, we like to investigate all devices with the Nessus and Nmap security scanners. Because of Teros Gateway's IP restrictions, attacks on the device itself are virtually impossible. Unless an attack is coming from one of your management stations, which you should maintain on a separate, secure network, an attacker would have little chance of getting to a live IP address. We give the product high marks for excellent security.

In addition, a setting in the initial installation makes the outside Internet IP invisible to anything but a real request.

What we liked

We liked the administrative GUI. It was attractive, simple and easy to use, and it was quickly responsive even though it was browser-based.

We give Teros high marks for hardening their device against attacks.

Teros Gateway offers three types of reports. All reports are simple, concise and suitable for submission to managers.

We also liked Teros Gateway's ability to dump and reload its complete configuration to a text file. In case of a disaster, this feature would be handy.

In high-volume situations, administrators would normally install a duplicate of the Teros appliance to provide failover and load-balancing capabilities. Company officials anticipated this and built capabilities to meet the needs.

Competing products

The Teros device is an application security gateway, a new class of products that protect applications from security problems, such as hacker attacks and confidential-data leaks. Several application security gateway products are on the market and each seems to take a different approach. We believe this industry is growing and will see a lot of activity in the next two years.

Conclusions and recommendations

Teros Gateway is a full-featured, high-quality application firewall capable of enforcing your applications' normal and intended behavior. The product's reporting and control features allow management of application-layer security. Teros Gateway is designed to protect a farm of Web servers.

If your organization runs critical or publicly accessible applications, this unit would be worthwhile for tightening security over the application traffic.

Greer is a network security consultant. Bishop operates PeoplesInformation.com, an Internet consulting firm. They can be reached at egreer@thecourageequation.com.