Music is made to affect people’s lives, not their computers.

A malware that infects multimedia files, modifying them to require the download of a fake codec when played had recently been discovered.

It infects widely used multimedia file formats such as MP3, WMA and WMV video files by injecting a malicious code. The said malware is also capable of converting files such as MP2 and MP3 into Windows Media Audio (WMA) format. When a user tries to play an infected file, a popup message is displayed, asking the user to download a certain codec in order to play the file. The downloaded codec is of course, nothing else but a malware.

Should the user choose to play the same file again after the “codec” had been installed, the popup will not appear anymore, which may drive the user into thinking that a codec was really installed on the system. But this is just the beginning, if the multimedia files are shared through a peer-to-peer network, anyone who downloads music or video file from an affected system will be at risk of getting infected as well.

Malware has posed as multimedia files and codecs to entice users into downloading malicious files. Here are reports on some of such instances in the past:

• Breaking News! Iran Invaded! Well…Maybe
• More Pop Culture Spam
• Malware Unleashes the Malware Beast
• ‘Roswell’ Victims Spill Beans on the Beijing Olympics
• Spammers Celebrate Classmates Day
• When Spam Promises the Stars

But this malware takes it to a new, and more dangerous level; it manipulates a person’s multimedia files and uses it against them. People normally keep thousands of multimedia files on their systems, especially MP3s. If each file is infected by the malware then shared through a P2P network, then the user unknowingly turns into a malware host.

Trend Micro threat engineers detect this malware as TROJ_MEDPINCH.A, and the embedded/encrypted executable file in it as TSPY_LDPINCH.ASG. The Trend Micro Smart Protection Network assesses the reputation of downloaded files, preventing users from ever having to deal with the hassles of restoring their MP3 collections back to their clean states.

Below is a screenshot of the spammed email message in the spam run we’ve been monitoring since last week (still pointing to the bogus PornTube page). Only this time, the landing page of the email link is not R.HTML, but rather MAIN.HTML.

Figure 1. Sample spam with the main.html link.

The following are some of the subject lines used:

• US government war brothels

• Barack Obama graft trial begins

• Obama outrageous lies exposed

• Iran announces completion of nuclear weapon

On the other hand, the email message bodies used included the following:

• Have a break, have a Kit Kat - free online chocolate bar giveaways

• Pump prices in the US jump 40% on announcement

• American kids found to have the highest level of cholesterol in latest health survey

• Millions outraged over Medicare benefit cuts across the board for all Americans

As of this writing, there are 44 MAIN.HTML URLs seen. As usual, the M.HTML landing page is peppered with links to a VIDEO.EXE file, which Trend Micro now detects as TROJ_AGENT.AKCF.

Here is a screenshot of the fake PornTube site:

Figure 2. Screenshot of the fake PornTube site.

Another infection vector that we have seen is through a legitimate Web site’s homepage. We have seen and are monitoring several homepages that have been inserted with the following meta tag:

The script file PERL.PHP will download an MSVideoCodec.exe binary. Trend Micro is currently processing a detection for the said executable file. The said .PHP file, meanwhile, apparently has IP logging, since going to the compromised page a second time will only redirect you to Google. This incident has all the trappings of a toolkit being uploaded to compromised sites. The question that remains is how have these sites been compromised in the first place?