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Virus Encyclopedia

Welcome to the Virus Encyclopedia of Panda Security.

Gaobot.OCC

Threat LevelHigh threatDamageSevereDistributionNot widespread
Common name:Gaobot.OCC
Technical name:W32/Gaobot.OCC.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 , across the Internet.
Affected platforms:

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

First detected on:Sept. 11, 2006
Detection updated on:Sept. 11, 2006
StatisticsNo
Proactive protection:
Yes, using TruPrevent Technologies

Brief Description 

    

Gaobot.OCC 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; screenshots of actions carried out.

It sends the gathered information to a remote user by any available means: email, FTP, etc.

 

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 terminates processes belonging to security tools, such as antivirus programs and firewalls, leaving the computer defenseless against attacks from other malware; it changes the security settings of Internet Explorer, decreasing its security level; it notifies the attacker that the computer has been compromised and is ready to be used maliciously; it awaits remote-control orders received through IRC or FTP; it changes system permissions, decreasing the security level.

 

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

  • It uses techniques included in its code to hide itself while it is active.
  • It terminates processes corresponding to several security tools, such as antivirus programs and firewalls, to prevent detection.
  • It deletes the original file from which it was run once it is installed on the computer.
  • It modifies system permissions in order to hide itself.

 

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

  • It terminates its own execution if it detects that a memory dump program is running, such as Procdump.
  • 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.

 

Gaobot.OCC 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.