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:

VB2018 preview: Unpacking the packed unpacker: reversing an Android anti-analysis library

At VB2018, Google researcher Maddie Stone will present an analysis of the multi-layered 'WeddingCake' anti-analysis library used by many Android malware families.

VB2018 preview: From drive-by download to drive-by mining

At VB2018, Malwarebytes researcher Jérôme Segura will discuss the rise of drive-by cryptocurrency mining, explaining how it works and putting it in the broader context of changes in the cybercrime landscape.

Red Eyes threat group targets North Korean defectors

A research paper by AhnLab researcher Minseok Cha looks at the activities of the Red Eyes threat group (also known as Group 123 and APT 37), whose targets include North Korean defectors, as well as journalists and human rights defenders focused on…

VB announces Threat Intelligence Summit to take place during VB2018

We are very excited to announce a special summit, as part of VB2018, that will be dedicated to all aspects of threat intelligence.

VB2018 Small Talk: An industry approach for unwanted software criteria and clean requirements

An industry approach for defining and detecting unwanted software to be presented and discussed at the Virus Bulletin conference.

We have placed cookies on your device in order to improve the functionality of this site, as outlined in our cookies policy. However, you may delete and block all cookies from this site and your use of the site will be unaffected. By continuing to browse this site, you are agreeing to Virus Bulletin's use of data as outlined in our privacy policy.