Backdoor.Pirpi.D is a Trojan that opens a back door on the victimized PC. Once run, Backdoor.Pirpi.D may download the configuration file. Backdoor.Pirpi.D registers itself as a service by creating the registry subkey. Backdoor.Pirpi.D may then open a back door on the compromised PC and contact a command-and-control (C&C) server using http on UDP port 501. Backdoor.Pirpi.D may also be set up to use a UDP port between 1 and 255. Backdoor.Pirpi.D then enables cybercrooks to obtain remote access to carry out various damaging actions on the infected computer. Backdoor.Pirpi.D can open a remote shell, receive information from the attacked PC (for example, the IP address and the current date), close IP connections, enumerate and kill any running processes, and block running itself. Backdoor.Pirpi.D may also control network traffic on the affected PC. Backdoor.Pirpi.D can also make modifications to the firewall configuration in order to disable warnings and accept the UDP communications that are being used by the malware infection.