Gaobot.OBC 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.OBC 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.
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