Adobe Systems on October 5th published that vulnerabilities regarding Adobe Reader 8.1 have been fixed. It can be downloaded here from the site for free. The updater, Version 8.1.0 applies to the 8.0 and 8.1-proved to fix the vulnerability.
The vulnerability, a Trojan horse “Pidief.A” discovered by Symantec was found in “Invoice” and “statement”, “bill”, such as the subject of e-mail, “invoice.pdf” “your_bill.pdf” “bill.pdf” “statement.pdf” etc as PDF file in attachment, which when open started a malware to download. The vulnerability has been confirmed in the version 8.1 and version 7.0.9, such as 3-D CAD model to support “Acrobat 3D,” also exist.