|Brontok.BJ is a worm with that has backdoor characteristics. Brontok.BJ spreads by copying itself, without infecting other files. Its main objective is to collapse computers and networks, thus preventing users from working on their computers.|
Furthermore, due to its backdoor characteristics, Brontok.BJ allows hackers to gain remote access to the affected computer. Therefore, hackers will be able to carry out actions that compromise user confidentiality and impede the tasks carried out on the computer.
It captures certain information entered or saved by the user, with the corresponding threat to privacy:
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 displays pop-up windows; causes system slowdowns; 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 opens one or more ports to allow remote access to the computer and takes action that compromises user confidentiality; it listens on open ports in order to control the computer remotely; it awaits remote-control orders received through
other channels; it changes system permissions, decreasing the security level.
Brontok.BJ prevents access from programs to websites of several companies related with security tools (antivirus programs, firewalls, etc.).
It uses stealth techniques to avoid being detected by the user:
- 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 prevents scanning tools from running, such as Windows Registry Editor, FileMonitor, etc.
Brontok.BJ 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.
- Email: sending emails that include a copy of itself as an attachment. The computer is infected when the attachment is run.
- Computer networks (mapped drives): it creates copies of itself in mapped drives.
- Computer networks (shared resources): it creates copies of itself in shared network resources to which it has access.