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Scammers skirt spam shields with help from Adobe Flash

The Viagra two step

Online scammers have found a new way to skirt anti-spam filters, this time by making use of Adobe Flash files hosted on free websites.

Spam messages with innocuous-looking content contain links to Flash-based files on ImageShack.com and elsewhere, according to a report from anti-spam service MessageLabs. Then commands embedded in the files redirect the recipient to sites that punt Viagra, work-at-home offers and free software updates.

The technique allows spammers to bypass content filters employed by many anti-spam products, which immediately nix messages that contain links to dodgy sites. Because popular sites such as ImageShack are whitelisted, use of the Flash file allows spammers to bypass the filter but still lure marks to sites that try to bilk them or trick them into installing malware.

"It seems a lot of the free image websites out there will quite happily accept a Flash file and attempt to display it," says Matt Sergeant, senior anti-spam technologist for MessageLabs. "The spammers basically get a free ride to bypass URL blocking."

As the series of images below show, the technique is being used to lure users to medsplacesuch.com, a site that claims to be an online pharmacy. It's also being used to trick users into installing software known as Antivirus XP 2008 (which we assume is a variation of a diabolical piece of malware also known as XP Antivirus 2008), and to a work-at-home site claimed to be operated by a company called Retoneva.

Spam with link to Flash file on ImageShack

Step 1: Spam with link to Flash file on ImageShack

Flash file contains code redirecting mark to dodgy site

Step 2: Flash file contains code redirecting mark to dodgy site

Mark is delivered to online pharmacy page

Step 3: Mark is delivered to online pharmacy page

Sergent said ImageShack has so far done a commendable job of removing malicious files once they are brought to the attention of employees in its abuse department. ®

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