Adobe Reader and Acrobat PDFs not safe until March

Users have been warned about a new threat from malicious PDF files that won't be fixed until next month, after Adobe's Reader and Acrobat were found to have a critical vulnerability.

In a security bulletin, Adobe warned that the security hole could cause the application to crash and potentially allows an attacker to take control of the affected system. It also said that criminals were already exploiting the flaw.

Adobe are planning to release updates to Adobe Reader and Acrobat to solve the issue, but warned that these wouldn't be available until 11 March. Adobe said that it was already in contact with anti-virus vendors such as McAfee and Symantec about the issue.

Adobe said users should update their virus definitions and be cautious when opening files from an untrusted source.

Graham Cluley, security consultant at Sophos, said on his blog that hackers could deliberately construct a malformed PDF file which could trigger the vulnerability, allowing them to open a backdoor and run malicious code on your computer.

He said: "This would mean that criminals, for instance, spam out a PDF file that would infect your PC, or plant malicious PDF content on a website.

"As PDF files are so widely used on the internet, and regularly exchanged to share this information, there is an obvious concern that hackers may be quick to take advantage of this vulnerability."