SECURTIY FIRM McAfee has discovered a vulnerability in Adobe's Reader program that allows people to track the usage of a PDF file.
"Recently, we detected some unusual PDF samples," McAfee's Haifei Li said in a blog post. "After some investigation, we successfully identified that the samples are exploiting an unpatched security issue in every version of Adobe Reader."
The affected versions of Adobe Reader also include the latest "sandboxed" Reader XI (11.0.2).
McAfee said that the issue is not a "serious problem" because it doesn't enable code execution, however it does permit the sender to see when and where a PDF file has been opened.
This vulnerability could only be dangerous if hackers exploited it to collect sensitive information such as IP address, internet service provider (ISP), or even the victim's computing routine to eventually launch an advanced persistent threat (APT).
McAfee said that it is unsure who is exploiting this issue or why, but have found the PDFs to be delivered by an "email tracking service" provider.
"Adobe Reader will access that UNC resource. However, this action is normally blocked and creates a warning dialog," Li said. "The danger is that if the second parameter is provided with a special value, it changes the API's behavior. In this situation, if the UNC resource exists, we see the warning dialog.
"However, if the UNC resource does not exist, the warning dialog will not appear even though the TCP traffic has already gone."
McAfee said that it has reported the issue to Adobe and is waiting for their confirmation and a future patch. Adobe wasn't immediately available for comment at the time of writing.