"Trojan" program is currently a relatively popular virus file. Unlike ordinary viruses, it does not reproduce itself and does not "intentionally" infect other files. It entices users to download and execute by disguising themselves as normal files. The trojan opens the portal of the seed computer so that the seed owner can destroy it arbitrarily, steal files from the seed computer, and even remotely control the seed computer. According to the above definitions, which of the following are main hazards caused by "trojan" programs? ['Corrupt System Files.', 'Reduce running speed.', 'Stealing user privacy.', 'Disguising normal files.']