Client-side vulnerabilities loom large

Critical vulnerabilities in common PC software, including both applications and operating systems, continue to grow in number and stand as the leading cause for concern in the IT security landscape today, according to training experts at the SANS Institute.

Holes in so-called client-side applications, including Web browsers, e-mail clients, productivity suites, and media players, have become particularly worrisome over the last year, according to SANS, which highlighted the issue as part of its annual report on the top 20 Internet security risks for 2007.

As hackers have shifted their attention further away from operating system flaws and drilled down to applications-layer vulnerabilities they have found a seemingly endless wealth of possibilities for infecting PCs with everything from spyware to botnet programs, SANS researchers contend.

Unless something can be done to improve software developers' coding habits or better test popular applications for such issues before they land on end-users' machines, attackers will be able to continue their successful assaults against enterprise networks and devices for the foreseeable future, said Rohit Dhamankar, project manager for the Top 20 report at SANS and a senior manager of security research for TippingPoint. 

"There's just been such a dramatic rise in the numbers of vulnerabilities found in applications like Internet Explorer and Microsoft Office and a number of media players that attackers are having their way," said Dhamankar. "Enterprises are bolstering security, but desktop users still pose a massive risk if they can download anything they want from the Web; the attacks are also growing in sophistication to the extent that many can defeat antivirus and other security systems primarily by obfuscating their code."

Some of the most powerful tools that hackers have adopted in hunting for potential targets are the same industrial-strength applications fuzzing tools that software vendors themselves are using to search for holes in their products, said the expert.

Enterprises could do themselves a favor by enforcing stricter policies that dictate the types of applications that end-users are allowed to put on their work machines and using technical means to ensure that those rules are being followed, Dhamankar said.

Other SANS researchers noted that while companies may not want to tell end-users that they cannot utilize media players, messaging clients, and other applications that have moved into the business world from the consumer sector, they could help themselves out by limiting the variety of client-side applications that people may choose from.

"IT departments can't focus on all the applications of the world, but they can choose several and keep their eye on those while allowing end-users some freedom," said Amol Sarwate, research manager at Qualys who studies vulnerability patterns for SANS. "What companies need to do is enforce standards for applications usage and utilize technical means to block unwanted software, devices, and even wireless access points."

While many businesses have already realized that they need to shift more of their efforts toward defending client-side vulnerabilities, most have failed to embrace a proactive approach versus simply keeping track of publicly-reported flaws and patching those issues said Sarwate.