最近需要参考下易企秀H5的json配置文件，发现已经做了加密，其实前端的加密分析起来只是麻烦点。

抓包分析

先看一个H5： https://h5.eqxiu.com/s/XvEn30op

F12可以看到，配置json地址是：https://s1-cdn.eqxiu.com/eqs/page/142626394?code=XvEn30op&time=1542972816000

对应的json：

{"success":true,"code":200,"msg":"操作成功","obj":"加密后的字符串"}

obj对应的是正式的配置信息

解码分析

需要对加密信息进行解密，首先可以定位到解密代码

function _0x230bc7(_0x2fb175) {

    return _0x3c31('0xee') == typeof _0x2fb175[_0x3c31('0x25')] && _0x2fb175['\x6f\x62\x6a'][_0x3c31('0xe')] > 0x64 ? _0x54c90c[_0x3c31('0x31f')]()['\x74\x68\x65\x6e'](function() {

        _0x249a60();

        var _0x5ab652 = null

          , _0x2cf0a4 = null

          , _0x4d1175 = null;

        try {

            var _0x3dbfaa = _0x2fb175[_0x3c31('0x25')]['\x73\x75\x62\x73\x74\x72\x69\x6e\x67'](0x0, 0x13)

              , _0x360e25 = _0x2fb175[_0x3c31('0x25')][_0x3c31('0xeb')](0x13 + 0x10);

            _0x2cf0a4 = _0x2fb175[_0x3c31('0x25')][_0x3c31('0xeb')](0x13, 0x13 + 0x10),

            _0x4d1175 = _0x2cf0a4,

            _0x5ab652 = _0x3dbfaa + _0x360e25,

            _0x2cf0a4 = CryptoJS['\x65\x6e\x63'][_0x3c31('0x320')][_0x3c31('0x6b')](_0x2cf0a4),

            _0x4d1175 = CryptoJS[_0x3c31('0x321')][_0x3c31('0x320')]['\x70\x61\x72\x73\x65'](_0x4d1175);

            var _0x57e61a = CryptoJS[_0x3c31('0x322')][_0x3c31('0x323')](_0x5ab652, _0x2cf0a4, {

                '\x69\x76': _0x4d1175,

                '\x6d\x6f\x64\x65': CryptoJS[_0x3c31('0x324')][_0x3c31('0x325')],

                '\x70\x61\x64\x64\x69\x6e\x67': CryptoJS[_0x3c31('0x326')][_0x3c31('0x327')]

            });

            return _0x2fb175[_0x3c31('0x36')] = JSON[_0x3c31('0x6b')](CryptoJS[_0x3c31('0x321')][_0x3c31('0x320')][_0x3c31('0x267')](_0x57e61a)),

            _0x2fb175;

        } catch (_0x36fffe) {

            _0x5ab652 = _0x2fb175[_0x3c31('0x25')]['\x73\x75\x62\x73\x74\x72\x69\x6e\x67'](0x0, _0x2fb175[_0x3c31('0x25')][_0x3c31('0xe')] - 0x10),

            _0x2cf0a4 = _0x2fb175[_0x3c31('0x25')][_0x3c31('0xeb')](_0x2fb175[_0x3c31('0x25')][_0x3c31('0xe')] - 0x10),

            _0x4d1175 = _0x2cf0a4,

            _0x2cf0a4 = CryptoJS[_0x3c31('0x321')][_0x3c31('0x320')][_0x3c31('0x6b')](_0x2cf0a4),

            _0x4d1175 = CryptoJS[_0x3c31('0x321')][_0x3c31('0x320')][_0x3c31('0x6b')](_0x4d1175);

            var _0x4ff7de = CryptoJS[_0x3c31('0x322')][_0x3c31('0x323')](_0x5ab652, _0x2cf0a4, {

                '\x69\x76': _0x4d1175,

                '\x6d\x6f\x64\x65': CryptoJS['\x6d\x6f\x64\x65'][_0x3c31('0x325')],

                '\x70\x61\x64\x64\x69\x6e\x67': CryptoJS[_0x3c31('0x326')][_0x3c31('0x327')]

            });

            return _0x2fb175[_0x3c31('0x36')] = JSON[_0x3c31('0x6b')](CryptoJS[_0x3c31('0x321')]['\x55\x74\x66\x38'][_0x3c31('0x267')](_0x4ff7de)),

            _0x2fb175;

        }

    }) : Promise[_0x3c31('0x1e')](_0x2fb175);

这个代码基本不可读，简单分析下可以发现，_0x3c31('0x321')对应一个字符串，'\x6f\x62\x6a'等也可以转义：

先转义：

function decode(xData) {

    return xData.replace(/\\x(\w{2})/g, function (_, $1) { return String.fromCharCode(parseInt($1, 16)) });

}

然后替换下：

Function.prototype.getMultiLine = function () {

    var lines = new String(this);

    lines = lines.substring(lines.indexOf("/*") + 3, lines.lastIndexOf("*/"));

    return lines;

}

function decode(xData) {

    return xData.replace(/\\x(\w{2})/g, function (_, $1) { return String.fromCharCode(parseInt($1, 16)) });

}

var str1 = function () {

    /*

   var _0x5ab652 = _0x50019d(_0x3c31('0x30c'))

, _0x2cf0a4 = _0x50019d('\x63\x6f\x6d\x70\x4b\x65\x79')

, _0x5cba8a = {

  '\x74\x79\x70\x65': _0x3c31('0x16c'),

  '\x75\x72\x6c': _0x8aa6f1()

}

, _0xfca4af = {

  '\x74\x79\x70\x65': _0x3c31('0x16c'),

  '\x75\x72\x6c': _0xefaeb()

};

_0x31f1b8 && (_0x5cba8a[_0x3c31('0x2cb')] = {

  '\x70\x61\x73\x73\x77\x6f\x72\x64': _0x31f1b8

});

var _0x11871b = null

, _0x170c7e = Promise[_0x3c31('0x1e')](null);

var _0x256cd0 = _0x2cf0a4(0x16)

, _0x36150e = _0x2cf0a4(0x15)

, _0x42a8d9 = _0x36150e['\x61\x6a\x61\x78']

, _0xdc46dc = _0x36150e[_0x3c31('0x1ef')]

, _0xcca797 = _0x2cf0a4(0x18)

, _0x50019d = _0xcca797[_0x3c31('0x5f')]

, _0x5c77e3 = _0xcca797['\x70\x61\x72\x73\x65\x55\x72\x6c']

, _0x36d54a = _0x2cf0a4(0x3a)['\x70\x65\x72\x66\x65\x63\x74\x4d\x65\x74\x61']

, _0x4c6a9e = _0x2cf0a4(0x2c)[_0x3c31('0x328')]

, _0x296a9b = _0x2cf0a4(0x2c)[_0x3c31('0x329')]

, _0x54c90c = _0x2cf0a4(0x17)

, _0x50f238 = _0x2cf0a4(0x3d)[_0x3c31('0x32a')]

, 0x13 = 0x13

, 0x0 = 0x0

, 0x10 = 0x10

, CryptoJS = null;

    function _0x230bc7(_0x2fb175) {

    return _0x3c31('0xee') == typeof _0x2fb175[_0x3c31('0x25')] && _0x2fb175['\x6f\x62\x6a'][_0x3c31('0xe')] > 0x64 ? _0x54c90c[_0x3c31('0x31f')]()['\x74\x68\x65\x6e'](function() {

        _0x249a60();

        var _0x5ab652 = null

          , _0x2cf0a4 = null

          , _0x4d1175 = null;

        try {

            var _0x3dbfaa = _0x2fb175[_0x3c31('0x25')]['\x73\x75\x62\x73\x74\x72\x69\x6e\x67'](0x0, 0x13)

              , _0x360e25 = _0x2fb175[_0x3c31('0x25')][_0x3c31('0xeb')](0x13 + 0x10);

            _0x2cf0a4 = _0x2fb175[_0x3c31('0x25')][_0x3c31('0xeb')](0x13, 0x13 + 0x10),

            _0x4d1175 = _0x2cf0a4,

            _0x5ab652 = _0x3dbfaa + _0x360e25,

            _0x2cf0a4 = CryptoJS['\x65\x6e\x63'][_0x3c31('0x320')][_0x3c31('0x6b')](_0x2cf0a4),

            _0x4d1175 = CryptoJS[_0x3c31('0x321')][_0x3c31('0x320')]['\x70\x61\x72\x73\x65'](_0x4d1175);

            var _0x57e61a = CryptoJS[_0x3c31('0x322')][_0x3c31('0x323')](_0x5ab652, _0x2cf0a4, {

                '\x69\x76': _0x4d1175,

                '\x6d\x6f\x64\x65': CryptoJS[_0x3c31('0x324')][_0x3c31('0x325')],

                '\x70\x61\x64\x64\x69\x6e\x67': CryptoJS[_0x3c31('0x326')][_0x3c31('0x327')]

            });

            return _0x2fb175[_0x3c31('0x36')] = JSON[_0x3c31('0x6b')](CryptoJS[_0x3c31('0x321')][_0x3c31('0x320')][_0x3c31('0x267')](_0x57e61a)),

            _0x2fb175;

        } catch (_0x36fffe) {

            _0x5ab652 = _0x2fb175[_0x3c31('0x25')]['\x73\x75\x62\x73\x74\x72\x69\x6e\x67'](0x0, _0x2fb175[_0x3c31('0x25')][_0x3c31('0xe')] - 0x10),

            _0x2cf0a4 = _0x2fb175[_0x3c31('0x25')][_0x3c31('0xeb')](_0x2fb175[_0x3c31('0x25')][_0x3c31('0xe')] - 0x10),

            _0x4d1175 = _0x2cf0a4,

            _0x2cf0a4 = CryptoJS[_0x3c31('0x321')][_0x3c31('0x320')][_0x3c31('0x6b')](_0x2cf0a4),

            _0x4d1175 = CryptoJS[_0x3c31('0x321')][_0x3c31('0x320')][_0x3c31('0x6b')](_0x4d1175);

            var _0x4ff7de = CryptoJS[_0x3c31('0x322')][_0x3c31('0x323')](_0x5ab652, _0x2cf0a4, {

                '\x69\x76': _0x4d1175,

                '\x6d\x6f\x64\x65': CryptoJS['\x6d\x6f\x64\x65'][_0x3c31('0x325')],

                '\x70\x61\x64\x64\x69\x6e\x67': CryptoJS[_0x3c31('0x326')][_0x3c31('0x327')]

            });

            return _0x2fb175[_0x3c31('0x36')] = JSON[_0x3c31('0x6b')](CryptoJS[_0x3c31('0x321')]['\x55\x74\x66\x38'][_0x3c31('0x267')](_0x4ff7de)),

            _0x2fb175;

        }

    }) : Promise[_0x3c31('0x1e')](_0x2fb175);

}"

  */

}

var js1 = decode(str1.getMultiLine());

js1 = js1.replace(/_0x3c31\('([^\']+)'\)/g, function ($v, $g) { return _0x3c31($g); })

得到

var _0x5ab652 = _0x50019d(userKey)

, _0x2cf0a4 = _0x50019d('compKey')

, _0x5cba8a = {

  'type': GET,

  'url': _0x8aa6f1()

}

, _0xfca4af = {

  'type': GET,

  'url': _0xefaeb()

};

_0x31f1b8 && (_0x5cba8a[data] = {

  'password': _0x31f1b8

});

var _0x11871b = null

, _0x170c7e = Promise[resolve](null);

var _0x256cd0 = _0x2cf0a4(0x16)

, _0x36150e = _0x2cf0a4(0x15)

, _0x42a8d9 = _0x36150e['ajax']

, _0xdc46dc = _0x36150e[$ajax]

, _0xcca797 = _0x2cf0a4(0x18)

, _0x50019d = _0xcca797[getUrlParam]

, _0x5c77e3 = _0xcca797['parseUrl']

, _0x36d54a = _0x2cf0a4(0x3a)['perfectMeta']

, _0x4c6a9e = _0x2cf0a4(0x2c)[isVipScene]

, _0x296a9b = _0x2cf0a4(0x2c)[isTgScene]

, _0x54c90c = _0x2cf0a4(0x17)

, _0x50f238 = _0x2cf0a4(0x3d)[setJsCrypto]

, 0x13 = 0x13

, 0x0 = 0x0

, 0x10 = 0x10

, CryptoJS = null;

    function _0x230bc7(_0x2fb175) {

    return string == typeof _0x2fb175[obj] && _0x2fb175['obj'][length] > 0x64 ? _0x54c90c[$loadCryptoJS]()['then'](function() {

        _0x249a60();

        var _0x5ab652 = null

          , _0x2cf0a4 = null

          , _0x4d1175 = null;

        try {

            var _0x3dbfaa = _0x2fb175[obj]['substring'](0x0, 0x13)

              , _0x360e25 = _0x2fb175[obj][substring](0x13 + 0x10);

            _0x2cf0a4 = _0x2fb175[obj][substring](0x13, 0x13 + 0x10),

            _0x4d1175 = _0x2cf0a4,

            _0x5ab652 = _0x3dbfaa + _0x360e25,

            _0x2cf0a4 = CryptoJS['enc'][Utf8][parse](_0x2cf0a4),

            _0x4d1175 = CryptoJS[enc][Utf8]['parse'](_0x4d1175);

            var _0x57e61a = CryptoJS[AES][decrypt](_0x5ab652, _0x2cf0a4, {

                'iv': _0x4d1175,

                'mode': CryptoJS[mode][CFB],

                'padding': CryptoJS[pad][NoPadding]

            });

            return _0x2fb175[list] = JSON[parse](CryptoJS[enc][Utf8][stringify](_0x57e61a)),

            _0x2fb175;

        } catch (_0x36fffe) {

            _0x5ab652 = _0x2fb175[obj]['substring'](0x0, _0x2fb175[obj][length] - 0x10),

            _0x2cf0a4 = _0x2fb175[obj][substring](_0x2fb175[obj][length] - 0x10),

            _0x4d1175 = _0x2cf0a4,

            _0x2cf0a4 = CryptoJS[enc][Utf8][parse](_0x2cf0a4),

            _0x4d1175 = CryptoJS[enc][Utf8][parse](_0x4d1175);

            var _0x4ff7de = CryptoJS[AES][decrypt](_0x5ab652, _0x2cf0a4, {

                'iv': _0x4d1175,

                'mode': CryptoJS['mode'][CFB],

                'padding': CryptoJS[pad][NoPadding]

            });

            return _0x2fb175[list] = JSON[parse](CryptoJS[enc]['Utf8'][stringify](_0x4ff7de)),

            _0x2fb175;

        }

    }) : Promise[resolve](_0x2fb175);

}"

基板上可以读了，使用CryptoJS做的前端解密，然后直接给最后的代码：

// 依赖： https://lib.eqh5.com/CryptoJS/1.0.1/cryptoJs.js

function decrypt(result) {

    var ciphertext = null

        , key = null

        , iv = null;

    try {

        var part0 = result.obj.substring(0x0, 0x13)

            , part1 = result.obj.substring(0x13 + 0x10);

        key = result.obj.substring(0x13, 0x13 + 0x10),

            iv = key,

            ciphertext = part0 + part1,

            key = CryptoJS.enc.Utf8.parse(key),

            iv = CryptoJS.enc.Utf8.parse(iv);

        var decryptData = CryptoJS.AES.decrypt(ciphertext, key, {

            'iv': iv,

            'mode': CryptoJS.mode.CFB,

            'padding': CryptoJS.pad.NoPadding

        });

        return CryptoJS.enc.Utf8.stringify(decryptData);

    } catch (_0x36fffe) {

        ciphertext = result[obj]['substring'](0x0, result.obj.length - 0x10),

            key = result[obj][substring](result.obj.length - 0x10),

            iv = key,

            key = CryptoJS.enc.Utf8.parse(key),

            iv = CryptoJS.enc.Utf8.parse(iv);

        var decryptData = CryptoJS.AES.decrypt(ciphertext, key, {

            'iv': iv,

            'mode': CryptoJS.mode.CFB,

            'padding': CryptoJS.pad.NoPadding

        });

        return CryptoJS.enc.Utf8.stringify(decryptData)

    }

}