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这个神奇的JavaScript代码如何工作?

作者:互联网

这是一小段警告“Hello world”的JavaScript代码:

゚ω゚ノ=/`m´)ノ~┻━┻//*´∇`*/['_'];o=(゚ー゚)=_=3;c=(゚Θ゚)=(゚ー゚)-(゚ー゚);(゚Д゚)=(゚Θ゚)=(o^_^o)/(o^_^o);(゚Д゚)={゚Θ゚:'_',゚ω゚ノ:((゚ω゚ノ==3)+'_')[゚Θ゚],゚ー゚ノ:(゚ω゚ノ+'_')[o^_^o-(゚Θ゚)],゚Д゚ノ:((゚ー゚==3)+'_')[゚ー゚]};(゚Д゚)[゚Θ゚]=((゚ω゚ノ==3)+'_')[c^_^o];(゚Д゚)['c']=((゚Д゚)+'_')[(゚ー゚)+(゚ー゚)-(゚Θ゚)];(゚Д゚)['o']=((゚Д゚)+'_')[゚Θ゚];(゚o゚)=(゚Д゚)['c']+(゚Д゚)['o']+(゚ω゚ノ+'_')[゚Θ゚]+((゚ω゚ノ==3)+'_')[゚ー゚]+((゚Д゚)+'_')[(゚ー゚)+(゚ー゚)]+((゚ー゚==3)+'_')[゚Θ゚]+((゚ー゚==3)+'_')[(゚ー゚)-(゚Θ゚)]+(゚Д゚)['c']+((゚Д゚)+'_')[(゚ー゚)+(゚ー゚)]+(゚Д゚)['o']+((゚ー゚==3)+'_')[゚Θ゚];(゚Д゚)['_']=(o^_^o)[゚o゚][゚o゚];(゚ε゚)=((゚ー゚==3)+'_')[゚Θ゚]+(゚Д゚).゚Д゚ノ+((゚Д゚)+'_')[(゚ー゚)+(゚ー゚)]+((゚ー゚==3)+'_')[o^_^o-゚Θ゚]+((゚ー゚==3)+'_')[゚Θ゚]+(゚ω゚ノ+'_')[゚Θ゚];(゚ー゚)+=(゚Θ゚);(゚Д゚)[゚ε゚]='\\';(゚Д゚).゚Θ゚ノ=(゚Д゚+゚ー゚)[o^_^o-(゚Θ゚)];(o゚ー゚o)=(゚ω゚ノ+'_')[c^_^o];(゚Д゚)[゚o゚]='\"';(゚Д゚)['_']((゚Д゚)['_'](゚ε゚+(゚Д゚)[゚o゚]+(゚Д゚)[゚ε゚]+(゚Θ゚)+(゚ー゚)+(゚Θ゚)+(゚Д゚)[゚ε゚]+(゚Θ゚)+((゚ー゚)+(゚Θ゚))+(゚ー゚)+(゚Д゚)[゚ε゚]+(゚Θ゚)+(゚ー゚)+((゚ー゚)+(゚Θ゚))+(゚Д゚)[゚ε゚]+(゚Θ゚)+((o^_^o)+(o^_^o))+((o^_^o)-(゚Θ゚))+(゚Д゚)[゚ε゚]+(゚Θ゚)+((o^_^o)+(o^_^o))+(゚ー゚)+(゚Д゚)[゚ε゚]+((゚ー゚)+(゚Θ゚))+(c^_^o)+(゚Д゚)[゚ε゚]+(゚ー゚)+((o^_^o)-(゚Θ゚))+(゚Д゚)[゚ε゚]+(゚Θ゚)+(゚Θ゚)+(c^_^o)+(゚Д゚)[゚ε゚]+(゚Θ゚)+(゚ー゚)+((゚ー゚)+(゚Θ゚))+(゚Д゚)[゚ε゚]+(゚Θ゚)+((゚ー゚)+(゚Θ゚))+(゚ー゚)+(゚Д゚)[゚ε゚]+(゚Θ゚)+((゚ー゚)+(゚Θ゚))+(゚ー゚)+(゚Д゚)[゚ε゚]+(゚Θ゚)+((゚ー゚)+(゚Θ゚))+((゚ー゚)+(o^_^o))+(゚Д゚)[゚ε゚]+(゚ー゚)+(c^_^o)+(゚Д゚)[゚ε゚]+(゚Θ゚)+((o^_^o)-(゚Θ゚))+((゚ー゚)+(o^_^o))+(゚Д゚)[゚ε゚]+(゚Θ゚)+((゚ー゚)+(゚Θ゚))+((゚ー゚)+(o^_^o))+(゚Д゚)[゚ε゚]+(゚Θ゚)+((o^_^o)+(o^_^o))+((o^_^o)-(゚Θ゚))+(゚Д゚)[゚ε゚]+(゚Θ゚)+((゚ー゚)+(゚Θ゚))+(゚ー゚)+(゚Д゚)[゚ε゚]+(゚Θ゚)+(゚ー゚)+(゚ー゚)+(゚Д゚)[゚ε゚]+(゚ー゚)+((o^_^o)-(゚Θ゚))+(゚Д゚)[゚ε゚]+((゚ー゚)+(゚Θ゚))+(゚Θ゚)+(゚Д゚)[゚o゚])(゚Θ゚))('_');

好看的版本:

゚ω゚ノ = /`m´)ノ~┻━┻//*´∇`*/['_'];
o = (゚ー゚) = _ = 3;
c = (゚Θ゚) = (゚ー゚) - (゚ー゚);
(゚Д゚) = (゚Θ゚) = (o^_^o)/(o^_^o);
(゚Д゚) = {
  ゚Θ゚:  '_',
  ゚ω゚ノ: ((゚ω゚ノ==3)+'_')[゚Θ゚],
  ゚ー゚ノ: (゚ω゚ノ+'_')[o^_^o-(゚Θ゚)],
  ゚Д゚ノ: ((゚ー゚==3)+'_')[゚ー゚]
};
(゚Д゚)[゚Θ゚] = ((゚ω゚ノ==3)+'_')[c^_^o];
(゚Д゚)['c'] = ((゚Д゚)+'_')[(゚ー゚)+(゚ー゚)-(゚Θ゚)];
(゚Д゚)['o'] = ((゚Д゚)+'_')[゚Θ゚];
(゚o゚)=(゚Д゚)['c'] + (゚Д゚)['o'] + (゚ω゚ノ + '_')[゚Θ゚] + ((゚ω゚ノ==3) + '_')[゚ー゚] + ((゚Д゚) + '_')[(゚ー゚) + (゚ー゚)] + ((゚ー゚==3) + '_')[゚Θ゚] + ((゚ー゚==3) + '_')[(゚ー゚) - (゚Θ゚)] + (゚Д゚)['c'] + ((゚Д゚) + '_')[(゚ー゚) + (゚ー゚)] + (゚Д゚)['o'] + ((゚ー゚==3) + '_')[゚Θ゚];
(゚Д゚)['_'] = (o^_^o)[゚o゚][゚o゚];
(゚ε゚) = ((゚ー゚==3) + '_')[゚Θ゚] + (゚Д゚).゚Д゚ノ + ((゚Д゚) + '_')[(゚ー゚) + (゚ー゚)] + ((゚ー゚==3) + '_')[o^_^o-゚Θ゚] + ((゚ー゚==3) + '_')[゚Θ゚] + (゚ω゚ノ+'_')[゚Θ゚];
(゚ー゚) += (゚Θ゚);
(゚Д゚)[゚ε゚] = '\\';
(゚Д゚).゚Θ゚ノ = (゚Д゚+゚ー゚)[o^_^o-(゚Θ゚)];
(o゚ー゚o) = (゚ω゚ノ+'_')[c^_^o];
(゚Д゚)[゚o゚] = '\"';
(゚Д゚)['_']((゚Д゚)['_'](゚ε゚+(゚Д゚)[゚o゚]+(゚Д゚)[゚ε゚]+(゚Θ゚)+(゚ー゚)+(゚Θ゚)+(゚Д゚)[゚ε゚]+(゚Θ゚)+((゚ー゚)+(゚Θ゚))+(゚ー゚)+(゚Д゚)[゚ε゚]+(゚Θ゚)+(゚ー゚)+((゚ー゚)+(゚Θ゚))+(゚Д゚)[゚ε゚]+(゚Θ゚)+((o^_^o)+(o^_^o))+((o^_^o)-(゚Θ゚))+(゚Д゚)[゚ε゚]+(゚Θ゚)+((o^_^o)+(o^_^o))+(゚ー゚)+(゚Д゚)[゚ε゚]+((゚ー゚)+(゚Θ゚))+(c^_^o)+(゚Д゚)[゚ε゚]+(゚ー゚)+((o^_^o)-(゚Θ゚))+(゚Д゚)[゚ε゚]+(゚Θ゚)+(゚Θ゚)+(c^_^o)+(゚Д゚)[゚ε゚]+(゚Θ゚)+(゚ー゚)+((゚ー゚)+(゚Θ゚))+(゚Д゚)[゚ε゚]+(゚Θ゚)+((゚ー゚)+(゚Θ゚))+(゚ー゚)+(゚Д゚)[゚ε゚]+(゚Θ゚)+((゚ー゚)+(゚Θ゚))+(゚ー゚)+(゚Д゚)[゚ε゚]+(゚Θ゚)+((゚ー゚)+(゚Θ゚))+((゚ー゚)+(o^_^o))+(゚Д゚)[゚ε゚]+(゚ー゚)+(c^_^o)+(゚Д゚)[゚ε゚]+(゚Θ゚)+((o^_^o)-(゚Θ゚))+((゚ー゚)+(o^_^o))+(゚Д゚)[゚ε゚]+(゚Θ゚)+((゚ー゚)+(゚Θ゚))+((゚ー゚)+(o^_^o))+(゚Д゚)[゚ε゚]+(゚Θ゚)+((o^_^o)+(o^_^o))+((o^_^o)-(゚Θ゚))+(゚Д゚)[゚ε゚]+(゚Θ゚)+((゚ー゚)+(゚Θ゚))+(゚ー゚)+(゚Д゚)[゚ε゚]+(゚Θ゚)+(゚ー゚)+(゚ー゚)+(゚Д゚)[゚ε゚]+(゚ー゚)+((o^_^o)-(゚Θ゚))+(゚Д゚)[゚ε゚]+((゚ー゚)+(゚Θ゚))+(゚Θ゚)+(゚Д゚)[゚o゚])(゚Θ゚))('_');

JSFiddle

它取自这里:https://codegolf.stackexchange.com/questions/23975/obfuscation-challenge/24041#24041

它是如何工作的?我甚至没有看到该代码中的警报.

解决方法:

在仔细查看代码之前,您必须知道,因为JavaScript 1.5 identifiers不仅包含ASCII字符,还包含Unicode字符.

在这种情况下,许多这些有趣的序列只是标识符.通过更简单的标识符交换这些标识符并删除不必要的注释和括号后,代码如下所示:

a = /`m´)ノ~┻━┻/['_'];
o = b = _ = 3;
c = d = b-b;
e = d = o^_^o/o^_^o;
e = {
  d: '_',
  a: ((a==3)+'_')[d],
  h: (a+'_')[o^_^o-d],
  i: ((b==3)+'_')[b]
};
e[d]   = ((a==3)+'_')[c^_^o];
e['c'] = (e+'_')[b+b-d];
e['o'] = (e+'_')[d];
f      = e['c']+e['o']+(a+'_')[d]+((a==3)+'_')[b]+(e+'_')[b+b]+((b==3)+'_')[d]+((b==3)+'_')[b-d]+e['c']+(e+'_')[b+b]+e['o']+((b==3)+'_')[d];
e['_'] = (o^_^o)[f][f];
g      = ((b==3)+'_')[d]+e.i+(e+'_')[b+b]+((b==3)+'_')[o^_^o-d]+((b==3)+'_')[d]+(a+'_')[d];
b      += d;
e[g]   = '\\';
e.j    = (e+b)[o^_^o-d];
obo    = (a+'_')[c^_^o];
e[f]   = '\"';
e['_'](e['_'](g+e[f]+e[g]+d+b+d+e[g]+d+(b+d)+b+e[g]+d+b+(b+d)+e[g]+d+((o^_^o)+(o^_^o))+((o^_^o)-d)+e[g]+d+((o^_^o)+(o^_^o))+b+e[g]+(b+d)+(c^_^o)+e[g]+b+((o^_^o)-d)+e[g]+d+d+(c^_^o)+e[g]+d+b+(b+d)+e[g]+d+(b+d)+b+e[g]+d+(b+d)+b+e[g]+d+(b+d)+(b+(o^_^o))+e[g]+b+(c^_^o)+e[g]+d+((o^_^o)-d)+(b+(o^_^o))+e[g]+d+(b+d)+(b+(o^_^o))+e[g]+d+((o^_^o)+(o^_^o))+((o^_^o)-d)+e[g]+d+(b+d)+b+e[g]+d+b+b+e[g]+b+((o^_^o)-d)+e[g]+(b+d)+d+e[f])(d))('_');

现在我们可以一次评估每个语句:

> a = /`m’)ノ〜┻━┻/ [‘_’]的计算结果为a = undefined
> o = b = _ = 3指定o,b和_整数3
> c = d = b-b分配c和d整数0
> e = d = o ^ _ ^ o / o ^ _ ^ o指定e和d整数1(o ^ _ ^ o计算结果为3 XOR 3 XOR 3,产生3)
> e = {d:’_’,a:((a == 3)’_’)[d],h:(a’_’)[o ^ _ ^ od],i :((b == 3)’_’)[b]}指定对象{d:’_’,a:’a’,h:’d’,i:’e’}
> e [d] =((a == 3)’_’)[c ^ _ ^ o]赋予e [1]字符串’f’
> e [‘c’] =(e’_’)[b b-d]为e [‘c’]指定字符串’c’
> e [‘o’] =(e’_’)[d]为e [‘o’]指定字符串’o’

这只是设置,并设置了以下变量:

a = undefined
b = 3
c = 0
d = 1
e = {
    1: "f",
    a: "a",
    c: "c",
    d: "_",
    h: "d",
    i: "e",
    o: "o"
}

下一个语句是第一个构造东西的语句:

f = e['c'] +             // => "c"
    e['o'] +             // => "o"
    (a+'_')[d] +         // => "undefined_"[1] = "n"
    ((a==3)+'_')[b] +    // => "false_"[3]     = "s"
    (e+'_')[b+b] +       // => "object_"[6]    = "t"
    ((b==3)+'_')[d] +    // => "true_"[1]      = "r"
    ((b==3)+'_')[b-d] +  // => "true_"[2]      = "s"
    e['c'] +             // => "c"
    (e+'_')[b+b] +       // => "object_"[6]    = "t"
    e['o'] +             // => "o"
    ((b==3)+'_')[d];     // => "true"[1]       = "r"

所以f =“构造函数”.在下一个语句中,这个“构造函数”用于检索函数:

e['_'] = (o^_^o)[f][f]

这相当于(3).constructor.constructor,它产生function Function,所以:

e['_'] = Function

这个Function函数是特殊的,因为可以通过参数传递函数体代码来动态构造函数:

f = Function("alert(1)")
// equivalent to
f = function() { alert(1) }

我将跳过接下来的几个语句,然后编写结果变量和值:

a = undefined
b = 4
c = 0
d = 1
e = {
    1: "f",
    _: Function,
    a: "a",
    c: "c",
    constructor: "\"",
    d: "_",
    h: "d",
    i: "e",
    j: "b",
    o: "o",
    return: "\\"
}
f = "constructor"
obo = "u"

最后一个陈述完成了最后的工作:

e['_'](e['_'](g+e[f]+e[g]+d+b+d+e[g]+d+(b+d)+b+e[g]+d+b+(b+d)+e[g]+d+((o^_^o)+(o^_^o))+((o^_^o)-d)+e[g]+d+((o^_^o)+(o^_^o))+b+e[g]+(b+d)+(c^_^o)+e[g]+b+((o^_^o)-d)+e[g]+d+d+(c^_^o)+e[g]+d+b+(b+d)+e[g]+d+(b+d)+b+e[g]+d+(b+d)+b+e[g]+d+(b+d)+(b+(o^_^o))+e[g]+b+(c^_^o)+e[g]+d+((o^_^o)-d)+(b+(o^_^o))+e[g]+d+(b+d)+(b+(o^_^o))+e[g]+d+((o^_^o)+(o^_^o))+((o^_^o)-d)+e[g]+d+(b+d)+b+e[g]+d+b+b+e[g]+b+((o^_^o)-d)+e[g]+(b+d)+d+e[f])(d))('_');

这相当于:

Function(Function( … )(1))('_')

long表达式构建以下字符串:

return"\141\154\145\162\164\50\42\110\145\154\154\157\40\127\157\162\154\144\42\51"

转义字符串计算:

alert("Hello World")

此返回代码传递给Function,它创建一个匿名函数,如:

function anonymous() {
    return"\141\154\145\162\164\50\42\110\145\154\154\157\40\127\157\162\154\144\42\51";
}

我们知道,相当于:

function anonymous() {
    return"alert(\"Hello World\")";
}

然后使用1作为参数执行此函数,该参数返回结果字符串:

alert("Hello World")

然后再将其传递给Function,这将创建一个新的匿名函数:

function anonymous() {
    alert("Hello World");
}

最后,还使用’_’作为参数调用此函数.

标签:deobfuscation,javascript,obfuscation
来源: https://codeday.me/bug/20191003/1850642.html