Sempo.A is a hacking tool that allows DoS (denial of service) attacks to be launched, in order to prevent legitimate users from accessing services.
DoS attacks are launched by sending a large number of service request packets from one computer to a specific server. This server is unable to answer to all the requests and is flooded, preventing legitimate users from accessing its services.
Sempo.A prevents access from programs to websites of several companies related with security tools (antivirus programs, firewalls, etc.).
Sempo.A redirects attempts to access web pages of certain banks to spoofed pages, with the aim of logging information entered by the user in these pages.
Sempo.A redirects attempts to access several web pages to a specific IP address.
Sempo.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.