Fake codec trojan disables anti-virus software

Posted by   Virus Bulletin on   Aug 5, 2011

Victim tricked into believing security software still active.

A new trojan, discovered by researchers at ESET, spreads itself via fake codecs, then disables running anti-virus solutions and makes the user believe that the anti-virus is still running.

The trojan spreads via Facebook chat and engages in a short, probably automated, conversation with the victim before showing them a link that appears to contain a video of them. The link points to a fake YouTube page where user is told to install an update to Flash Player before they can view the video. This 'fake codec' trick has been used by malware authors for quite some time; in this case the attackers have added to the apparent authenticity of the link by leaving comments on the video which make it appear as if other users also had to update, but that they thought it was 'worth the effort'.

Of course, the Flash 'update' is in fact a trojan, dubbed Win32/Delf.QCZ by ESET. Upon installation, the malware detects which anti-virus solution is being used on the computer and attempts to disable it by removing its directory. To do so, it makes changes to the registry and needs to have the computer restarted in safe mode. If the user does not do so manually, a (fake) anti-virus warning pops up informing them about an 'incurable' virus which requires a reboot to be removed.

Upon de-activation of the anti-virus software, its icon is left in the system tray, thus fooling the user into believing it is still running and their computer is still protected. Clicking the icon, however, gives another fake warning that the AV software is running in 'advanced protection mode'.

Having thus disabled protection of the victim's machine, the trojan opens a backdoor which is used to install other malware onto the system.

Posted on 05 August 2011 by Virus Bulletin

twitter.png
fb.png
linkedin.png
googleplus.png
reddit.png

 

Latest posts:

A crime against statistics that is probably worse than the cyber attacks faced in County Durham

A report on the number of cyber attacks faced by UK local authorities is a good example of how the large numbers seen in many reports on security are rather meaningless.

NCSC gives important advice on lateral movement

The UK's National Cyber Security Centre (NCSC) has provided helpful and practical advice on preventing and detecting lateral movement by an attacker within a network.

What kind of people attend Virus Bulletin conferences?

If you are considering submitting a proposal for a talk to VB2018 and you're not familiar with the event, you may find it useful to know what kind of people attend the conference.

Olympic Games target of malware, again

An unattributed malware attack has disrupted some computer systems of the 2018 Winter Olympics. In 1994, a computer virus also targeted the Winter Olympics.

There are lessons to be learned from government websites serving cryptocurrency miners

Thousands of websites, including many sites of government organisations in the UK, the US and Sweden, were recently found to have been serving a cryptocurrency miner. More interesting than the incident itself, though, are the lessons that can be…