Successful exploits need not be zero-day attacks. In fact, it is often older vulnerabilities in popular applications that are the doorknob intruders turn to compromise systems.
This point was underscored recently by separate research from Qualys and Trusteer highlighting some troublesome findings in the patch management process.
According to the July 28 Qualys report, (PDF) the half-life of vulnerabilities-the time it takes for 50 percent of systems to be patched-is now typically 29.5 days. The majority of vulnerabilities are now found in client-side applications, with most targeted attacks hitting Adobe Acrobat/Reader and Microsoft Word.
This time to remediation is virtually unchanged from 2004, though Qualys admits a direct comparison is difficult because of the sheer number of vulnerabilities today and the maturity of modern vulnerability management tools. Still, Qualys CTO Wolfgang Kandek said he was struck by the fact that while IT administrators have gotten good at patching OS vulnerabilities, admins are still taking a lot of time to address vulnerabilities in applications.
"Businesses have to test the patch deployment to assure that patches do not break existing applications," Kandek said. "At the same time, attackers are getting better [able] to explore new vulnerabilities ever faster. Companies will have to find a way to patch machines faster. We believe that dividing machines into fast and slow patch pools is a valid strategy ... [and] that certain applications should be patched quicker than others; for example, Internet Explorer on desktops, Office Applications [and] Adobe Reader are applications that are attacked constantly and should be kept updated aggressively."
Qualys' statistics are backed up by a study released by security company Trusteer Aug. 13, (PDF) which reported that nearly 80 percent of the roughly 2.5 million users Trusteer scanned are running vulnerable versions of Flash, and nearly 84 percent are using vulnerable versions of Acrobat Reader. The danger of leaving security holes open for long periods is underscored by Microsoft's Intelligence Report for the second half of 2008, which revealed that 91.3 percent of attacks against Microsoft Office exploited a vulnerability that was patched more than two years ago (CVE-2006-2492).
Eric Ogren, principal analyst of the Ogren Group, said he was surprised to see that the overall time to patch had not improved in the past several years. But the biggest surprises for him in Qualys' findings were the mess and inattention at the desktop.
"I have talked with a bunch of IT folks about patching and I tend to get data center answers," Ogren said. "I get the need to validate and critique patches for apps-only a moron would apply patches to a data base system without rigorous testing. But I do not always detect a sense of urgency for the desktop-particularly apps such as the browser, MS Office and Adobe."
Ogren added, "IT has to know that users have Adobe, Media Player, iPhone [software], etc., and should look to accelerate patching of application software."