The spokeswoman added that no vulnerabilities that could be used to escape the sandbox have been reported to Adobe since Reader X debuted last November. "Nor have we seen any public discussion of sandbox-breaking exploits," she said.
That's good news for Adobe, which even before Reader X's launch had argued that security researchers would be looking for bugs in its sandbox. "Everyone will want bragging rights to be the first to come up with a working exploit of the sandbox," said Brad Arkin, Adobe's director of security and privacy, in an October 2010 interview.
Reader X's sandbox is based on technologies used by Google and Microsoft. The former sandboxes its Chrome browser, for example, while the latter uses similar defenses to protect Internet Explorer and Office 2010 on Windows.
Adobe also claimed that a recently-addressed bug in Chrome that lets attackers escape the browser's sandbox was not present in Reader X's sandbox code.
Google patched that bug, the first to earn the reporting researcher the company's top bug bounty of $3,133, three weeks ago.
Also on Thursday, Adobe alerted customers that it would ship its next quarterly security update for Reader on Tuesday, Feb. 8.
Next week's Reader update will patch the Windows and Mac versions, including Reader X.
Sophos' Wisniewski urged Windows users to upgrade as soon as possible to take advantage of the sandbox defense. "Reader X is the most secure version of the program, and everyone should be using it," he said.
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