Web Encryption That Works

Download the entire Dark Reading March 2012 Supplement

For years, Secure Sockets Layer encryption methods have been fundamental to Web security. Recent attacks have called into question whether SSL and the follow-on protocol, Transport Layer Security, are the best ways to authenticate websites. Critics say these methods are vulnerable and difficult to deploy, but most industry experts insist they aren't fundamentally broken--they just need to be implemented better.

SSL and TLS, both commonly referred to as SSL, are being used in all corners of the Web to authenticate that a website is actually the one it says it is and not a fake launched by phishers and other attackers to obtain confidential data. SSL also provides the encryption infrastructure to share data securely. It's so entrenched, and the prospect of ripping and replacing it with a different technology so onerous, that a wholesale change to a new method isn't likely to happen. Given its ubiquity, improving how website operators deploy and implement SSL looks like our best choice in the near term. (Read more on future prospects here.)

"Even if we did decide that it's fully compromised and broken right now, it would probably be 10 years before you could actually have something meaningful replacing it if you started today," says Brian Trzupek, VP of managed identity and authentication for Trustwave, a certificate authority and security services vendor. The most recent version of SSL-based technology--TLS 1.2--has fixed the known problems. The vulnerabilities that remain are "in the periphery of how SSL is implemented," says Trzupek.

The SSL trust ecosystem isn't perfect, but there are steps website operators can take to optimally deploy SSL, avoiding mistakes that can jeopardize companies' data and put customers at risk. Here are four places to start.

Use Up-To-Date Protocols, Cipher Suites

SSL is an elegantly engineered protocol that can withstand many types of attacks. But that statement comes with one big caveat: To be fully protected, a website must use the most up-to-date SSL protocol and cipher suites, and its servers must be properly configured.

But many IT organizations don't do a good job with this. "Most SSL servers are misconfigured," contends Ivan Ristic, director of engineering at Qualys, an IT security services provider that has scanned 1.2 million website servers to study SSL deployment trends. "Only about one-third of the servers we saw that use SSL are properly configured. That's the best we can do at the moment."

The vast majority of servers still use a version of SSL that's two revisions behind the most current technology, according to Qualys. In the same way it's critical to patch endpoints with the latest, most secure software updates, it's important for companies to use up-to-date versions of SSL to minimize vulnerabilities that attackers can leverage to carry out session hijacking and other sophisticated attacks.

Similarly, businesses need to think carefully about the cipher technologies they're using with the SSL protocol that do the actual encrypting.

"Try to choose the biggest, most complex encryption keys you can that will reasonably work on all of the devices they need to work on," Trzupek says. Ideally, companies should use 256-bit cipher strength or stronger.

This is a big factor in properly configuring SSL on a Web server, Ristic says, but there are plenty of other areas to watch for, especially at the application layer.

Of the SSL-enabled sites that Qualys examined, SSL generally wasn't implemented well at the application layer, he says. Even sites that have well-configured SSL at the protocol level often construct the Web applications and sites in ways that "completely compromise SSL and make it easy for an attacker to exploit that problem," he says.

For example, many Web applications fail to encrypt the authentication form that gets users started using the app. "It surprised even us," Ristic says. "People are entering their user names and passwords in plain text, and attackers are routinely catching those."

Another common misconfiguration is not adequately securing session cookies when they're deployed, giving attackers easy access to them. Cookies must have the word "secure" coded into them in order to be safe from prying eyes. "Even if you have a well-configured SSL server, if you don't mark your session cookies secure, ... an attacker may be able to take the cookie out and hijack the session," Ristic says. Developers need to watch for these errors when creating new applications, he says. With existing applications, it's much more difficult to retrofit fixes every time a vulnerability is identified.