Confirming a zero-day "Xmas exploit" that targets both Adobe Acrobat and Reader, Symantec said in a Tuesday statement that the exploit is apparently prompted by a Trojan hidden in the PDF attachments opened unwarily by e-mail recipients.

In a statement confirming the vulnerability, Symantec said in an official blog post that though the organization did not discover this vulnerability, it has received a number of reports of the issue and has inspected multiple diverse copies of malicious PDFs that exploit this issue.

Adding that the malicious Adobe Acrobat PDF file is distributed through e-mail attachments, Symantec said that the execution of the exploit follows the opening of the attachment on a fully patched system on which either Adobe Acrobat or Reader has been installed.

Explaining the exploit, which has also been corroborated by ShadowServer, Symantec said: "When the file is opened, a malicious file is dropped and run on a fully patched system with either Adobe Reader or Acrobat installed. We detect the file as Trojan. Pidief. H."

The Symantec post also said that while several tests have confirmed this is a zero-day vulnerability affecting different Adobe Acrobat and Reader versions, including Acrobat 9.2 and earlier for Windows and Macintosh, as well as Reader 9.2 and earlier for Windows, Macintosh, and Unix.

So far as the protection of the system from the vulnerability is concerned, Symantec has recommended the disabling JavaScript.