1. Symantec/
  2. Security Response/
  3. Backdoor.Shellbot


Risk Level 1: Very Low

June 3, 2005
April 30, 2010 3:46:09 AM
Systems Affected:
Backdoor.Shellbot is a detection name used by Symantec to identify malicious software programs that share the primary functionality of enabling a remote attacker to have access to or send commands to a compromised computer.

As the name suggests, these threats are used to provide a covert channel through which a remote attacker can access and control a computer. The Trojans vary in sophistication, ranging from those that only allow for limited functions to be performed to those that allow almost any action to be carried out, thus allowing the remote attacker to almost completely take over control of a computer.

A computer with a sophisticated back door program installed may also be referred to as a "zombie" or a "bot". A network of such bots may often be referred to as a "botnet". Botnets have been well publicized in the news over the years, with different instances being given specific names such as Kraken, Mariposa, or Kneber, along with claims of hundreds of thousands of nodes belonging to certain networks.

Typical back door capabilities may allow a remote attacker to:
  • Collect information (system and personal) from the computer and any storage device attached to it
  • Terminate tasks and processes
  • Run tasks and processes
  • Download additional files
  • Upload files and other content
  • Report on status
  • Open remote command line shells
  • Perform denial of service attacks on other computers
  • Change computer settings
  • Shut down or restart the computer

Back door Trojan horse programs have become increasingly popular amongst malware creators over the years because of the shift in motivation from fame and glory to money and profit. In today's black market economy, a computer with a back door can be put to work performing various criminal activities that earn money for their controllers. Schemes such as pay per install, sending spam emails, and harvesting personal information and identities are all ways to generate revenue.

If a Symantec antivirus product displays a detection alert for this threat, it means the computer is already protected and the Symantec product will effectively remove this threat from the computer.

Antivirus Protection Dates

  • Initial Rapid Release version June 3, 2005
  • Latest Rapid Release version January 21, 2018 revision 005
  • Initial Daily Certified version June 3, 2005
  • Latest Daily Certified version January 21, 2018 revision 008
  • Initial Weekly Certified release date June 8, 2005
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
Writeup By: Hon Lau and Henry Bell

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2016 Internet Security Threat Report, Volume 21
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