Trj/SysSrv.A is a Trojan, which although seemingly inoffensive, can actually carry out attacks and intrusions.
It reduces the security level of the computer:
it changes the security settings of Internet Explorer, decreasing its security level.
It uses stealth techniques to avoid being detected by the user:
- It injects itself in running processes.
- 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.
- It terminates its own execution if it detects that a debugging program is active.
Trj/SysSrv.A 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.