Alert level

TrojanDownloader:Win32/Zlob


Encyclopedia entry
Updated: Dec 10, 2007  |  Published: Feb 20, 2006

Aliases
  • TROJ_ZLOB (Trend Micro)

Alert Level (?)
Severe

Antimalware protection details
Microsoft recommends that you download the latest definitions to get protected.
Detection last updated:
Definition: 1.71.240.0
Released: Nov 25, 2009
Detection initially created:
Definition: 1.45.287.0
Released: Oct 07, 2008


Summary

TrojanDownloader:Win32/Zlob is generic detection for a component of the greater Win32/Zlob malware family. Win32/Zlob refers to a large multi-component family of malware that modifies Internet Explorer's settings, alters and redirects the user's default Internet search page and home page, and attempts to download and execute arbitrary files (including additional malicious software). The Win32/Zlob family has also been associated with rogue security programs that display misleading warnings regarding bogus malware infections.


Symptoms

The following system change may be indicative of a TrojanDownloader:Win32/Zlob infection:
  • Infection warning messages are displayed.


Technical Information (Analysis)

TrojanDownloader:Win32/Zlob is generic detection for a component of the greater Win32/Zlob malware family. Win32/Zlob refers to a large multi-component family of malware that modifies Internet Explorer's settings, alters and redirects the user's default Internet search page and home page, and attempts to download and execute arbitrary files (including additional malicious software). The Win32/Zlob family has also been associated with rogue security programs that display misleading warnings regarding bogus malware infections.


Prevention

Take the following steps to help prevent infection on your system:
  • Enable a firewall on your computer.
  • Get the latest computer updates.
  • Use up-to-date antivirus software.
  • Use caution with attachments and file transfers.

Enable a firewall on your computer

Use a third-party firewall product or turn on the Microsoft Windows XP Internet Connection Firewall.
To turn on the Internet Connection Firewall in Windows XP
  1. Click Start, and click Control Panel.
  2. Click Network and Internet Connections. If you do not see Network and Internet Connections, click Switch to Category View.
  3. Click Change Windows Firewall Settings.
  4. Select On.
  5. Click OK.

Get the latest computer updates

Updates help protect your computer from viruses, worms, and other threats as they are discovered. You can use the Automatic Updates feature in Windows XP to automatically download future Microsoft security updates while your computer is on and connected to the Internet.
To turn on Automatic Updates in Windows XP
  1. Click Start, and click Control Panel
  2. Click System.
  3. Click Automatic Updates.
  4. Select a setting. Microsoft recommends selecting Automatic. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.

Use up-to-date antivirus software

Most antivirus software can detect and prevent infection by known malicious software. To help protect you from infection, you should always run antivirus software that is updated with the latest signature files. Antivirus software is available from several sources. For more information, see http://www.microsoft.com/athome/security/downloads/default.mspx

Use caution with attachments and file transfers

Exercise caution with e-mail and attachments received from unknown sources, or received unexpectedly from known sources.  Use extreme caution when accepting file transfers from known or unknown sources.


Recovery

Manual removal is not recommended. To detect and remove this Trojan and other malicious software that may have been installed, run a full-system scan with an up-to-date antivirus product such as the Microsoft online scanner (http://safety.live.com). For more information, visit http://www.microsoft.com/athome/security/downloads/default.mspx.