At long last, Adobe Systems has added a new security protection to Windows versions of its ubiquitous document reader that's designed to lock down one of the world's most exploited applications.

The so-called sandbox, isolates Reader from sensitive Windows operations, such as the changing of operating system registry settings and the modification of sensitive files. The new feature, dubbed Protected Mode, is intended to lessen the damage malicious hackers can wreak when they exploit buffer overflows and similar flaws that inevitably arise in any piece of complex software.

“While sandboxing is not a security silver bullet, it provides a strong additional level of defense against attacks,” Brad Arkin, Adobe's senior director of product security and privacy, wrote here. “Even if exploitable security vulnerabilities are found by an attacker, Adobe Reader Protected Mode will help prevent the attacker from writing files or installing malware on potential victims’ computers.”

Adding the technology to an existing piece of software is a monumental task, developers have said. To make Protected Mode as effective as possible, Arkin said Adobe engineers worked with counterparts at Google and Microsoft, which have fortified the Chrome Browser and Office and Internet Explorer respectively with a similar feature. Mozilla Firefox has yet to add sandboxing, and has provided no timetable for doing so.

Reader's automatic updating feature has yet to alert us to the availability of new version, which is called Reader X, and it's not clear when that might happen. Those who want to download it immediately may do so here. While Protected Mode is available only for Windows, Reader X is also available for Mac OS X and Android. ®