AVAST Software researchers have discovered that six out of every ten users of Adobe Reader are running unpatched versions of the program, leaving them vulnerable to a variety of malware attacks.
An analysis of avast! antivirus users found that 60.2% of those with Adobe Reader were running a vulnerable version of the program and only 40% of users had the newest Adobe Reader X or were fully patched. One out of every five users also had an unpatched version of Adobe Reader that was at least two generations old (8.x).
Adobe Reader is the most popular PDF reader application and subsequently is the biggest target for malware writers. Over 80% of avast! users run a version of Adobe Reader, with Foxit, the second most popular PDF reader, having a much smaller user share of 4.8%.
“There is a basic assumption that people will automatically update or migrate to the newer version of any program. At least with Adobe Reader, this assumption is wrong – and it’s exposing users to a wide range of potential threats,” said Ondrej Vlcek, CTO at AVAST Software.
Brad Arkin, senior director of product security and privacy at Adobe, agreed with the AVAST analysis. “We find that most consumers don’t bother updating a free app such as Adobe Reader as PDF files can be viewed in the older version,” he said. “In many cases, users only update when provisioning a new machine.” He added that the avast! data on user vulnerabilities was “definitely believable” with Adobe finding significant variations in the update behavior of consumer and corporate users: “When I visit friends at home, I tend to find the older versions.”
Malware PDF exploit packages will typically look for a variety of security weaknesses in the targeted computer, attacking when an uncovered vulnerability is discovered. “Most exploits have been made to hit all vulnerable versions, not just one,” explained Mr. Vlcek. “Libraries of code are shared between various Adobe versions which also means that vulnerabilities are shared.”
Updates are the key security issue as the AVAST Virus Lab did not detect a causal link between specific versions of Adobe Reader and exposure to malware.
“It is actually possible to be fully patched and up-to-date if you are running Adobe Reader 8 or 9,” stated Mr. Arkin, “But I think a large percentage of users simply decline the update notification.”
Keeping secure, especially for the older versions of Adobe Reader, does require some user attention. “It is critical for users to stay updated,” said Mr Arkin. The preferred response is for users to update to Adobe Reader X with Protected View (aka “sandboxing”). Windows users should also and opt into the automatic update option. “Our hope is that with the automatic update and the latest Adobe Reader X offering, we will see a measurable improvement on these statistics. We are really eager to get more users updated to the latest, most secure versions as quickly as possible.”