Agentdoc.d is a trojan that drops malicious files on the infected computer. Once executed, the parasite installs itself to the system along with the keylogger that logs all user keystrokes and transfers gathered data to a predetermined web site. Agentdoc.d also opens a back door providing the attacker with unauthorized access to the compromised computer. The intruder can control the infected system and access user confidential inforamation. The trojan uses an integrated rootkit to hide its files and registry entries, and therefore avoid detection. It also injects malicious code into the Internet Explorer process. Agentdoc.d runs on every Windows startup.