Legmir.UH is a Trojan, which although seemingly inoffensive, can actually carry out attacks and intrusions. It captures certain information entered or saved by the user, with the corresponding threat to privacy:
passwords saved by certain Windows services. 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:
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.
It reduces the security level of the computer:
it changes the security settings of Internet Explorer, decreasing its security level; it opens one or more ports to allow remote access to the computer and takes action that compromises user confidentiality; 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 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.
- It terminates its own execution if it detects that a memory dump program is running, such as Procdump.
- It terminates its own execution if it detects that a debugging program is active.
Legmir.UH 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. |