Agysteo.Q is a rootkit. These are programs used to hide files, Windows Registry entries or processes, either their own or those of other programs.
In this way, even when a user looks for these items on a computer, they won't be able to see them.
Rootkits have been widely used for malicious ends, to camouflage other programs on computers that have previously been compromised through other means.
There are certain examples of malware that use rootkits in order to go unnoticed on the computer they have infected.
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 injects itself in running processes.
- 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.
Agysteo.Q does not spread automatically using its own means. It needs an attacking user's intervention in order to reach the affected computer. The means of transmission used include, among others, floppy disks, CD-ROMs, email messages with attached files, Internet downloads, FTP, IRC channels, peer-to-peer (P2P) file sharing networks, etc.