Parent class: VirWare

Viruses and worms are malicious programs that self-replicate on computers or via computer networks without the user being aware; each subsequent copy of such malicious programs is also able to self-replicate. Malicious programs which spread via networks or infect remote machines when commanded to do so by the “owner” (e.g. Backdoors) or programs that create multiple copies that are unable to self-replicate are not part of the Viruses and Worms subclass. The main characteristic used to determine whether or not a program is classified as a separate behaviour within the Viruses and Worms subclass is how the program propagates (i.e. how the malicious program spreads copies of itself via local or network resources.) Most known worms are spread as files sent as email attachments, via a link to a web or FTP resource, via a link sent in an ICQ or IRC message, via P2P file sharing networks etc. Some worms spread as network packets; these directly penetrate the computer memory, and the worm code is then activated. Worms use the following techniques to penetrate remote computers and launch copies of themselves: social engineering (for example, an email message suggesting the user opens an attached file), exploiting network configuration errors (such as copying to a fully accessible disk), and exploiting loopholes in operating system and application security. Viruses can be divided in accordance with the method used to infect a computer:
  • file viruses
  • boot sector viruses
  • macro viruses
  • script viruses
Any program within this subclass can have additional Trojan functions. It should also be noted that many worms use more than one method in order to spread copies via networks.

Class: Virus

Viruses replicate on the resources of the local machine. Unlike worms, viruses do not use network services to propagate or penetrate other computers. A copy of a virus will reach remote computers only if the infected object is, for some reason unrelated to the virus function, activated on another computer. For example: when infecting accessible disks, a virus penetrates a file located on a network resource a virus copies itself to a removable storage device or infects a file on a removable device a user sends an email with an infected attachment.

Read more

Platform: Win32

Win32 is an API on Windows NT-based operating systems (Windows XP, Windows 7, etc.) that supports execution of 32-bit applications. One of the most widespread programming platforms in the world.


Technical Details

This is a parasitic Windows virus with backdoor ability. When an infected file is run, the virus-installing routine takes control, creates the DLLMGR.EXE file in the Windows system directory and spawns it. The DLLMGR.EXE file is a pure virus code, it stays in the Windows memory as a hidden application and registers its file (DLLMGR.EXE) in the system registry in the auto-run section (this will cause Windows to load and run this file upon each startup):

  Teddybear = "xxxxDLLMGR.EXE"

where "xxxx" is the name of the Windows system directory.

The virus then stays in Windows memory and its "backdoor" routine gains control. This routine opens the connection and waits for commands from remote host, gets/sends files from/to there, etc. The virus is also able to execute files that are sent by a host (including a virus update). Moreover, the virus code in the DLLMGR.EXE file (dropped to the system by the infected file) has no infection code in it. The infecting routine is downloaded from the host and executed. So, the infection and other virus routines are stand-alone executable files, and they can be easily updated by the virus' author. Very similar technology was used for the first time in the Win95_Babylonia Windows virus.

The known virus version and components are compatible with Win9x only, and do not work under WinNT. They also have bugs that stop the virus from spreading in some cases. Despite this, new bugs-free and NT-compatible components may be released by virus author.

Read more

Find out the statistics of the vulnerabilities spreading in your region on

Found an inaccuracy in the description of this vulnerability? Let us know!
Kaspersky Next
Let’s go Next: redefine your business’s cybersecurity
Learn more
New Kaspersky!
Your digital life deserves complete protection!
Learn more
Confirm changes?
Your message has been sent successfully.