By analyzing the vulnerabilities of IEEE 802.11 protocol, and based on the scheme of capturing, filtering and analyzing frames, the algorithm for cracking WEP protocol key was put forward to intruding the target host in WLAN. Then combined with the key technologies of Trojans such as the covert and anti-killing, a remote monitoring framework based on the mechanism of Trojans was designed. According to practical requirements, some forensics methods were provided in the framework such as screen monitoring and file management. Experiments results show that the forensics system was of high reliabi...