According to a report released on Tuesday by Secunia Research, now part of Flexera Software, Adobe Flash Player 18 reached end-of-life on Sept. 22, and is no longer supported by Adobe with patches and updates.
Flash has been in the cross-hairs of the tech industry for several years now, with Apple refusing to support it on iPhones back in 2007, and YouTube defaulting to the open-source HTML 5 alternative at the beginning of this year and no longer offering Flash to modern browsers in September. Google also began blocking Flash ads this fall. Netfix and Twitch are also switching to HTML 5 for their videos.
In fact, the number of websites using Flash has fallen from nearly 30 percent five years ago to 9.8 percent of websites today, according to W3Techs.
"In the past year, we've seen an increase in the number of end-of-life products on US PCs," said Kasper Lindgaard, director of research and security at Secunia ApS.
Today, 5.5 percent of all installed software has passed its expiration date, he said.
"A year ago, the number was steady at between three and four percent," he added. "We can't say anything definite about why that is, but we will be keeping an eye on how it develops."
Other applications that have reached the end of their support periods but still have significant market share on user computers include Microsoft XML Core Services 4.x with 67 percent market share, Oracle Java JRE 1.7.x and 7.x with 35 percent market share, Google Chrome 44 and 43 with 35 percent and 24 percent respective market share, Mozilla Firefox 39 and 40 with 24 percent and 21 percent respective market share, Adobe Air 18.x with 17 percent market share, Oracle Java JRE 1.6.x and 6.x with 16 percent market share, and Adobe Air 3.x with 13 percent market share.
Oracle's Java 7 hit its end of life mark last spring.
Kasper Lindgaard, director of research and security at Secunia ApS
Previously, the software had been at the top of unpatched software lists for a long time, said Lindgaard.
"It has had a relatively large market share and been unpatched on a very high percentage of private PCs," he said. "Oracle Java 8, which only has a 40 percent market share, is the only Java product in the Top 10. It doesn’t get to the top of the list because Java 8 doesn’t have a large market share yet and the patch status is better than it was for version 7."
At this time last year, Oracle Java JRE 1.7.x and 7.x was on 66 percent of PCs, and 42 percent of the installations were unpatched, making it the most exposed program on the list.
Now, Apple has taken the lead, with Apple QuickTime 7.x in first place with a 55 percent market share and a 61 percent unpatched rate. And Apple's iTunes 12.x is in second place, with a 40 percent market share and a 47 percent unpatched rate.
Last year, these two products were in second place and fifth place, respectively.
"We're used to seeing Apple products on the list," Lindgaard said.
But whether software is unpatched because users aren't updating it, or it's end-of-life and patches are no longer issued, it still poses a significant risk for users.
Instead of finding new ways to break into a computer, hackers can just use one of the many known exploits available for these old or unpatched applications.
"Too many users install and forget," Lindgaard said. "Maintenance of software is not high on the radar of the average computer users, who tend to install whatever application they need to support whatever they need to do. They then tend to leave it sitting in their system, forgetting to uninstall or update it."
For enterprises, this means that they need to not only be aware of the applications that run on corporate-owned machines, but also on personal computers that employees use to access corporate networks and other company assets, he said.
"A vulnerable application on a device that is connected to a corporate environment poses a potential threat," he said.