病毒注解：绕过安全性控制而获取对程序或系统访问权的方法。在软件的开发阶段，程序员常会在软件内创建后门以便可以修改程序中的缺陷。如果后门被其他人知道，或是在发布软件之前没有删除后门，那么它就成了安全风险。
这也有可能是个木马
清除木马的步骤：
打开注册表Regedit
点击目录至：
HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
删除右边的‘c:windows
otpa.exe /o=yes‘
关闭Regedit，重新启动到MSDOS系统中
删除c:windows
otpa.exe
注意：不要删除真正的notepad.exe笔记本程序
危害级别：1
说明：
中文名称—“后门”， 是指在用户不知道也不允许的情况下，在被感染的系统上以隐蔽的方式运行可以对被感染的系统进行远程控制，而且用户无法通过正常的方法禁止其运行。“后门”其实是木马的一种特例，它们之间的区别在于“后门”可以对被感染的系统进行远程控制（如：文件管理、进程控制等）。
英文释义Backdoor:
a. 秘密的
英英解释:
名词backdoor:
1. an undocumented way to get access to a computer system or the data it contains
同义词：back door
2. an entrance at the rear of a building
同义词：back door, back entrance
3. a secret or underhand means of access (to a place or a position)
同义词：back door
DOTA 中的 Backdoor 战术
又称偷塔
越兵拆塔
小鸡偷渡到对方家附近
飞鞋全体转移
下面是英文原义
The act of attacking enemy buildings in their respective base while allied creeps are not inside the base together with the hero(es).
Base: Any building opposed to your side of the team, beginning from the third-line towers protecting the barracks to the Frozen Throne or Tree of Life.
Allied creep(s): Creep(s) generated only by the barracks, and excludes summoned units, i.e. Furion's (Prophet) Forces of Nature, Black Arachnia's (Broodmother) Spawn Spiderlings, Necronomicon's Demon Mages, etc., creep(s) under spell/item effect(s), i.e. Aiustha's (Enchantress) Enchant, Chen's (Holy Knight) Holy Persuasion, Helm of Dominator's effect, etc., image(s), i.e. Azwraith (Phantom Lancer), Slithice (Naga Siren), Terrorblade (Soul Keeper), Manta Style effect, etc., and so on.
It is not considered as backdoor as long as there are allied creeps in the base, no matter which lane those creeps were generated from.
Backdooring is allowed IF AND ONLY IF either one of these conditions are fulfilled:
For game(s) which has equal number of players in each team when game started:
The number of players on each team must be the same, e.g. 5v5, 4v4, 3v3.
The team of the backdooring player has a lower number of the opposing team, e.g. 4v5, 3v4, 2v3.
For game(s) which has different number of players in each team when game started:
No number-of-players restrictions apply for backdooring, i.e. Any player(s) can choose to backdoor anytime, anywhere regardless the number of remaining players in the game.
In ANY case, backdooring The Throne/World Tree is not allowed.
