Updated A proof of concept virus which has the potential to infect Flash files commonly used on Web sites has been discovered.
The SWF/LFM-926 virus, which could infect surfers if they download and then open a Flash file on their PC, is the first of its kind, according to antivirus vendor Sophos. Simply viewing a Web site or Flash movie fails to cause infection, early tests suggest.
"The virus is not yet in the wild, but it is clear proof that virus writers continue to search for new ways to infect computer users," said Graham Cluley, senior technology consultant for Sophos Anti-Virus.
SWF/LFM-926 only infects other Macromedia Flash files but the technique could be applied to create viruses with more damaging payloads, he warned.
Sophos recommends webmasters put in place procedures and policies to ensure the integrity of the code they place on sites, whether it is obviously executable (in the case of, for instance, exe and com files) or Flash movies.
Existence of the SWF/LFM-926 virus came to light after the virus author emailed a copy of the virus to Sophos, which has exchanged samples of the bug with other security vendors. Apart from making sure AV products check SWF files, the emergence of the technique doesn't mandate changes in security software. ®
Macromedia has issued a statement clarifying that the issue affects only Macromedia Flash and not Shockwave content, which is produced using Director Shockwave studio, a different product.
A patch for Macromedia Flash will be available latter this week, the firm promises. More information can be found here.
Antivirus vendors, and our initial report, referred to Shockwave Flash but this is inaccurate: .SWF used to stand for Shockwave Flash file format, but now it's just Flash.