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Virus Encyclopedia

Welcome to the Virus Encyclopedia of Panda Security.


Threat LevelModerate threatDamageHighDistributionNot widespread
Common name:Downloader.MDW
Technical name:Trj/Downloader.MDW
Threat level:Low
Effects:   It allows to get into the affected computer. It generates a large amount of network traffic activity with the consequent consumption of bandwidth. It carries out actions that decrease the security level of the computer. It uses anti-monitoring techniques in order to prevent it being detected by antivirus companies. It spreads , across the Internetand also by being downloaded by other malware.
Affected platforms:

Windows 2003/XP/2000/NT/ME/98/95

First detected on:Jan. 2, 2007
Detection updated on:June 19, 2010
Proactive protection:
Yes, using TruPrevent Technologies

Brief Description 


Downloader.MDW is a Trojan, which although seemingly inoffensive, can actually carry out attacks and intrusions.


  • In the local network: it generates a large amount of network activity and consumes bandwidth.


It reduces the security level of the computer: it notifies the attacker that the computer has been compromised and is ready to be used maliciously; it changes system permissions, decreasing the security level.


It uses several methods in order to avoid detection by antivirus companies:

  • It terminates its own execution if it detects that it is being executed in a virtual machine environment, such as VMWare or VirtualPC.


Downloader.MDW uses the following propagation or distribution methods:

  • Exploiting vulnerabilities with the intervention of the user: exploiting vulnerabilities in file formats or applications. To exploit them successfully it needs the intervention of the user: opening files, viewing malicious web pages, reading emails, etc.
  • Via Internet, exploiting remote vulnerabilities: attacking random IP addresses, in which it tries to insert a copy of itself by exploiting one or more vulnerabilities.
  • It is dropped or downloaded to the computer by other malware specimens, for example: Autorun.F, Multidropper.RGX, Multidropper.RHQ, Multidropper.RHR, Multidropper.RHS, Multidropper.RHT, Multidropper.RHU, Dropper.YB, Dropper.YL, Multidropper.RJU, Multidropper.RJV, Multidropper.RMO, Multidropper.RNB, Multidropper.RNO, Rustock.G, Hupigon.LDN, Delf.AJF, Downloader.MLA, Downloader.MUF, Downloader.PZX, Downloader.RET, Downloader.RHH, Downloader.RHI, Buzus.AO, Downloader.VFD, Spammer.ALU.