Kolabc.BU is a worm that spreads by copying itself, without infecting other files. 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.
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 listens on open ports in order to control the computer remotely; 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 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.
- It prevents scanning tools from running, such as Windows Registry Editor, FileMonitor, etc.
- It terminates its own execution if it detects that a debugging program is active.
Kolabc.BU 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.
- IRC: It sends a copy of itself to all users connected to the channel to which the infected user is connected.
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