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Virus Encyclopedia

Welcome to the Virus Encyclopedia of Panda Security.

Gaobot.NLA

Threat LevelHigh threatDamageSevereDistributionNot widespread
Common name:Gaobot.NLA
Technical name:W32/Gaobot.NLA.worm
Threat level:Medium
Type:Worm
Effects:   It spreads and affects other computers. It captures certain information entered or saved by the user, with the corresponding threat to privacy. It affects the productivity of the computer, the network to which it’s connected or other remote sites. It carries out actions that decrease the security level of the computer. It uses stealth techniques to avoid being detected by the user. It uses anti-monitoring techniques in order to prevent it being detected by antivirus companies. It spreads by exploiting vulnerabilities, across the Internet.
Affected platforms:

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

First detected on:June 16, 2006
Detection updated on:June 16, 2006
StatisticsNo
Proactive protection:
Yes, using TruPrevent Technologies

Brief Description 

    

Gaobot.NLA is a worm that spreads by copying itself, without infecting other files.

 

It captures certain information entered or saved by the user, with the corresponding threat to privacy: passwords saved by certain Windows services; keystrokes, in order to obtain information for accessing online banking services, passwords and other confidential information.

 

It affects productivity, preventing tasks from being carried out:

  • In the affected computer: it converts the computer into a platform for taking malicious action surreptitiously: spam sending, launch of Denial of Service attacks, malware distribution, etc.
  • In the local network: it generates a large amount of network activity and consumes bandwidth.

 

It reduces the security level of the computer: it opens one or more ports to allow remote access to the computer and takes action that compromises user confidentiality; it awaits remote-control orders received through IRC; it changes system permissions, decreasing the security level.

 

It uses stealth techniques to avoid being detected by the user:

  • It deletes the original file from which it was run once it is installed on the computer.

 

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.
  • Its code is encrypted and it is only decrypted when it is going to run. Because of this, its code is not legible through a memory dump.
  • It terminates its own execution if it detects that a debugging program is active.

 

Gaobot.NLA 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.