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社区首页 >专栏 >【JS逆向百例】云汉芯商城逆向分析

【JS逆向百例】云汉芯商城逆向分析

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K哥爬虫
发布2024-03-25 14:34:36
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发布2024-03-25 14:34:36
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文章被收录于专栏:Python 爬虫Python 爬虫
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声明

本文章中所有内容仅供学习交流使用,不用于其他任何目的,不提供完整代码,抓包内容、敏感网址、数据接口等均已做脱敏处理,严禁用于商业用途和非法用途,否则由此产生的一切后果均与作者无关!

本文章未经许可禁止转载,禁止任何修改后二次传播,擅自使用本文讲解的技术而导致的任何意外,作者均不负责,若有侵权,请在公众号【K哥爬虫】联系作者立即删除!

前言

继上次粉丝提问,K哥出了对应站点的分析文章之后,又有不少小伙伴提出了在逆向一些网站的时候碰到的问题,态度都很友好,K哥会尽力满足粉丝需求,不过只能一个个慢慢来,本文先对其中一个进行逆向分析:

01
01

逆向目标

  • 目标:某芯商城,逆向分析
  • 网页:aHR0cHM6Ly9zZWFyY2guaWNrZXkuY24vP2tleXdvcmQ9RVJKVTAzRjEwMDJW

逆向过程

抓包分析

打开开发者人员工具,随便搜索一个型号的芯片,在 Network 中即会抓包到相应的数据接口,即 /search/ajax-get-res-v001

02
02

请求参数如下,keyword 大概率就是加密的搜索内容,v_ 是固定值,font_identp_csrf 都会动态变化,需要逐个研究分析:

03
03

该网站存在风控,会弹出极验四代语序点选的验证码,这里就不赘述了,感兴趣的可以阅读K哥往期文章 【验证码逆向专栏】极验三代、四代点选类验证码逆向分析

04
04

逆向分析

keyword 参数

该接口是 XHR(XMLHttpRequest)类型的请求,可以直接下个 XHR 断点,这样定位到的位置通常在加密处理完成之后,已经准备发送请求了,优点是便于踪栈,更容易找到加密的地方。在开发者人员工具 Source 面板右侧的 XHR/fetch Breakpoints 中添加截取的接口 URL:

05
05

刷新网页即会断住:

06
06

向上跟栈到 ajax 中,于 send 处打下断点,F8 下步断点,断过来,可以看到,此时 keyword 参数的值是明文,也就是搜索的芯片型号:

07
07

接下来就需要找一下这段明文是在哪被加密的,向上跟栈到 psB-acac185595.js 中,很明显,该 js 经过了 OB 混淆(Obfuscator),感兴趣的可以使用 AST 技术解一下,关键的加密逻辑大概率就藏在这里面。跟到下图处,出现了几个接口所需的请求参数,这里的 keyword 仍是明文状态:

08
08

直接在 psB-acac185595.js 中 ctrl+f 搜索 keyword,总共有 23 个结果,不多,逐个分析下,在可能是加密算法的位置打断点分析,ERJU03F1002V 在下图处被加密成了 RVJKVTAzRjEwMDJW

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09

跟进到 _0x7f9865[_0xfe4009(0x82c)] 函数中,直接把算法扣下来:

代码语言:javascript
复制
function orOperator(_0x1e4532, _0x39fc6b) {
    return _0x1e4532 | _0x39fc6b;
}
​
function andOperator(_0x241af9, _0x10df1e) {
            return _0x241af9 & _0x10df1e;
        }
function lessCompare(_0x58aa60, _0x251729) {
    return _0x58aa60 < _0x251729;
}
​
function RightShiftOperator(_0x50cbd4, _0x2a3840) {
    return _0x50cbd4 >> _0x2a3840;
}
​
function addOperator(_0xea955f, _0x17d167) {
    return _0xea955f + _0x17d167;
}
​
function utf8Encode(_0xe407f5) {
    _0xe407f5 = _0xe407f5["replace"](/\r\n/g, '\x0a');
    for (var _0xeefa10 = '', _0x4fcfd7 = 0x0; _0x4fcfd7 < _0xe407f5["length"]; _0x4fcfd7++) {
        var _0x1451bf = _0xe407f5["charCodeAt"](_0x4fcfd7);
        lessCompare(_0x1451bf, 0x80) ? _0xeefa10 += String["fromCharCode"](_0x1451bf) : _0x1451bf > 0x7f && _0x1451bf < 0x800 ? (_0xeefa10 += String["fromCharCode"](_0x1451bf >> 0x6 | 0xc0),
            _0xeefa10 += String["fromCharCode"](orOperator(0x3f & _0x1451bf, 0x80))) : (_0xeefa10 += String["fromCharCode"](orOperator(_0x1451bf >> 0xc, 0xe0)),
            _0xeefa10 += String["fromCharCode"](_0x1451bf >> 0x6 & 0x3f | 0x80),
            _0xeefa10 += String["fromCharCode"](0x3f & _0x1451bf | 0x80));
    }
    return _0xeefa10;
}
​
function encryptKeyword(_0x3a29c2) {
    let keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
    let _0x40e006, _0x2e7dee, _0x2f707d, _0x70f89f, _0x1d4342, _0x55ace3, _0xee897c, _0x482490 = '',
        _0x4326f6 = 0x0;
    for (_0x3a29c2 = utf8Encode(_0x3a29c2); _0x4326f6 < _0x3a29c2["length"];)
        _0x40e006 = _0x3a29c2["charCodeAt"](_0x4326f6++),
            _0x2e7dee = _0x3a29c2["charCodeAt"](_0x4326f6++),
            _0x2f707d = _0x3a29c2["charCodeAt"](_0x4326f6++),
            _0x70f89f = _0x40e006 >> 0x2,
            _0x1d4342 = (0x3 & _0x40e006) << 0x4 | RightShiftOperator(_0x2e7dee, 0x4),
            _0x55ace3 = (0xf & _0x2e7dee) << 0x2 | _0x2f707d >> 0x6,
            _0xee897c = andOperator(0x3f, _0x2f707d),
            isNaN(_0x2e7dee) ? _0x55ace3 = _0xee897c = 0x40 : isNaN(_0x2f707d) && (_0xee897c = 0x40),
            _0x482490 = addOperator(addOperator(_0x482490, keyStr.charAt(_0x70f89f)) + keyStr.charAt(_0x1d4342), keyStr.charAt(_0x55ace3)) + keyStr.charAt(_0xee897c);
    return _0x482490;
}
​
let searchKeyWord = "ERJU03F1002V";
let searchKeyWordEncryptResult = encryptKeyword(searchKeyWord);
console.log(searchKeyWordEncryptResult);  // RVJKVTAzRjEwMDJW

我们来分析下这是什么算法,倒着看,_0x70f89f_0x1d4342 之类的是一些十进制数,keyStr.charAt(_0x70f89f) 就是获取 keyStr 字符串特定位置的字符值,最后拼接起来:

代码语言:javascript
复制
_0x482490 = addOperator(addOperator(_0x482490, keyStr.charAt(_0x70f89f)) + keyStr.charAt(_0x1d4342), keyStr.charAt(_0x55ace3)) + keyStr.charAt(_0xee897c);

keyStr 就是源码中的 this["_keyStr"],其值如下,长度为 65 位:

代码语言:javascript
复制
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=

这一串完全符合 Base64 编码索引表的特征,包含大写字母(A-Z)、小写字母(a-z)、数字(0-9)、加号(+)和斜杠(/),64 位,还有一个填充字符(=),Base64 编码的基本流程如下,例如编码 Hello 字符串:

  1. 首先,将 Hello 转换为 ASCII 码,得到 72 101 108 108 111
  2. 然后,每三个字节一组(数据块,不足三个则在末尾填充零),得到 72 101 108108 111 0
  3. 每组的三个 ASCII 码,分别转为八位二进制数,不足的在前面补 0,比如 72 101 108 得到 01001000 01100101 01101100,首尾相连,形成 24 位的二进制数;
  4. 将 24 位的二进制数,拆分为四个 6 位的小组;
  5. 将每组二进制数转换为十进制,并从 Base64 索引表中查找对应的字符;
  6. 使用填充字符 "=" 添加到编码结果的末尾,以保证编码结果的长度为 4 的倍数。

ASCII 码表和 Base64 索引表可于公众号回复关键词 ascii 或 base64 获取,Base64 编码图解:

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10

其实该数据接口对于 Base64 编码也有所提示 乛◡乛:

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11

可以去 K哥爬虫工具站 验证一下,结果一致:

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12

至此 keyword 参数就分析完成了。

v 参数

前文提到几个加密参数都在一块,如下图所示,断住后观察一下,v_0x501622,定义在上面几行,就是 13 位时间戳:

代码语言:javascript
复制
_0x501622 = JSON["stringify"](new Date()["getTime"]());
13
13

font_ident

font_ident 直接从 this 中取到,其值不是通过加密算法生成的,在该网页的源代码中,可以直接使用 xpath 或者正则表达式匹配出来:

14
14

p 参数

p 参数值长度为 32 位,看着很像是 MD5 加密,我们来跟一下,p 参数在下图处生成:

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15

跟到 _0x101cba[_0xfe4009(0x412) 函数中去,p 参数的值就是 window['x']

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16

直接 hook 一下 window 中的 x 参数,断住后跟栈分析,使用 Fiddler 或者油猴之类的都可以,hook 脚本如下:

代码语言:javascript
复制
(function() {
    'use strict';
    Object.defineProperty(window, 'x', {
        get: function() {
            debugger;
            return "";
        },
        set: function(value) {
            debugger;
            return value;
        },
    });
})();

刷新网页,成功断住,此时 window['x'] 的值已经生成了:

17
17

向上跟栈到 VM 中,可以看到 window.x = hex_md5('xxx'),这里像是 MD5 加密的源码:

18
18

我们直接拿加密内容去爬虫工具站测试一下,发现值并不一样,这里的 MD5 算法可能经过了魔改:

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19

先直接将整段代码扣下来,保存到本地,简单改改能直接运行:

20
20

来看看传入的 17104110xxx 是什么,接着向上跟栈到下图处,这里的逻辑就很有意思了,_0x4c3be9 就是 MD5 加密的参数:

代码语言:javascript
复制
eval(_0x24f5ec["decode"](_0x2b037f)["replace"]("mwqqppz", "'" + _0x4c3be9 + "'"));
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21

跟进到 _0x24f5ec["decode"] 函数中分析一下,取消 hook,断进去,_0xc8f1ce 就是 _0x2b037f,是一个固定的字符串,这里的算法逻辑是不是很眼熟,和 keyword 参数一样,是 base64,不过这里是解码的过程,将一大串字符串还原成了刚刚的 MD5 算法,用 replace 方法替换 mwqqppz 字符串传入待加密值,最后使用 eval 方法执行解码出的 JavaScript 代码,实现加密操作:

22
22

接着跟栈分析 17104110xxx,跟到 handleParamsV1 中去,加密参数就是由 p1p2_code 三个参数拼接而成的:

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23

往后跟下栈就会发现,p1 参数是个时间戳,其值和前文所讲的 v 参数的值相同,p2_ 就是搜索的芯片型号经过 base64 编码后得到的值,code 定义如下:

代码语言:javascript
复制
tmp = $.md5(p1 + p2_)
, code = eval(window.relwarckcuf + '("' + tmp + '")');

与前面的不同,$.md5 使用的是标准的 MD5 加密算法:

24
24

window.relwarckcuf 的值会变化,其值需要从该页面的源代码中获取:

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25

生成 code 同样使用到了 eval 方法,逻辑就是将 tmp 参数值传到了 window.relwarckcuf 函数中,生成了最终的 code 值,较为别致,跟进到这个函数中去:

26
26

跳转到 79baf82e5b7315e32957b68b5b3d0260 文件中,这个文件名是会动态变化的,每次刷新页面都不一样,同样可以从网页源代码中提取出来,完整链接 https://search.ickey.cn/x/c/79baf82e5b7315e32957b68b5b3d0260

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27

就是套了两个 switch,做了些运算,不同文件 4|1|2|3|6|5|0 的顺序会变,但算法的执行顺序其实是固定的,唯一会变的值就是 _0x5b2c03['lQMEJ'],先将函数部分扣下来:

28
28

JavaScript 代码:

代码语言:javascript
复制
function xb9397d46e271a79d37e14478d0bbd99d(_0x3589bd) {
    var _0x5b2c03 = {
        'NMqMe': function(_0xf40245, _0x5f3db1) {
            return _0xf40245 < _0x5f3db1;
        },
        'dutuH': function(_0x305515, _0x16b9ff) {
            return _0x305515 % _0x16b9ff;
        },
        'FgcEp': function(_0x4f1496, _0x4a009b) {
            return _0x4f1496 / _0x4a009b;
        },
        'Krfyp': function(_0x5e7e97, _0x3a2b65) {
            return _0x5e7e97 - _0x3a2b65;
        },
        'cuUNs': function(_0x482dab, _0x2d4aa7) {
            return _0x482dab / _0x2d4aa7;
        },
        'KYiBU': function(_0x63165e, _0x35b40d) {
            return _0x63165e + _0x35b40d;
        },
        'vAfft': function(_0x59664e, _0x587b82) {
            return _0x59664e + _0x587b82;
        },
        'lQMEJ': "abcd"
    }
      , _0x34838f = "4|1|2|3|6|5|0"["split"]('|')
      , _0xdf0619 = 0x0;
    while (!![]) {
        switch (_0x34838f[_0xdf0619++]) {
        case '0':
            return _0x27369a;
        case '1':
            var _0x5c31de = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
            continue;
        case '2':
            var _0x5e9e9b = 36;
            continue;
        case '3':
            var _0x7c3dbb = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'];
            continue;
        case '4':
            var _0x27369a = '';
            continue;
        case '5':
            for (var _0xb3aee8 = 0x0; _0x5b2c03['NMqMe'](_0xb3aee8, 32); _0xb3aee8++) {
                var _0x34f9cc = "4|0|5|2|3|1|6"["split"]('|')
                  , _0x1ff8ce = 0x0;
                while (!![]) {
                    switch (_0x34f9cc[_0x1ff8ce++]) {
                    case '0':
                        _0x1da465 = _0x5b2c03["dutuH"](_0x3b7479, _0x5e9e9b);
                        continue;
                    case '1':
                        _0x3a7eff = _0x5b2c03["dutuH"](_0x3b7479, _0x5e9e9b);
                        continue;
                    case '2':
                        _0x38b5d0 = _0x5b2c03["dutuH"](_0x3b7479, _0x5e9e9b);
                        continue;
                    case '3':
                        _0x3b7479 = _0x5b2c03["FgcEp"](_0x5b2c03["Krfyp"](_0x3b7479, _0x38b5d0), _0x5e9e9b);
                        continue;
                    case '4':
                        _0x3b7479 = _0x3589bd["charCodeAt"](_0xb3aee8);
                        continue;
                    case '5':
                        _0x3b7479 = _0x5b2c03["cuUNs"](_0x5b2c03["Krfyp"](_0x3b7479, _0x1da465), _0x5e9e9b);
                        continue;
                    case '6':
                        _0x27369a += _0x5b2c03["KYiBU"](_0x5b2c03["KYiBU"](_0x5b2c03["vAfft"](_0x7c3dbb[_0x3a7eff], _0x7c3dbb[_0x38b5d0]), _0x7c3dbb[_0x1da465]), _0x5b2c03["lQMEJ"]);
                        continue;
                    }
                    break;
                }
            }
            continue;
        case '6':
            var _0x3b7479, _0x1da465, _0x38b5d0, _0x3a7eff;
            continue;
        }
        break;
    }
}
console.log(xb9397d46e271a79d37e14478d0bbd99d('9b6ed790af9bae4b109a79870590af51'));

Python 复现:

代码语言:javascript
复制
def get_md5_encrypt_str(_0x3589bd):
    dynamic_parameter = 'abcd'
    _0x27369a = ''
    _0x5e9e9b = 36
    _0x7c3dbb = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I',
                 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z']
    _0x3b7479, _0x1da465, _0x38b5d0, _0x3a7eff = 0, 0, 0, 0
    for _0xb3aee8 in range(len(_0x3589bd)):
        _0x3b7479 = ord(_0x3589bd[_0xb3aee8])
        _0x1da465 = _0x3b7479 % _0x5e9e9b
        _0x3b7479 = int((_0x3b7479 - _0x1da465) / _0x5e9e9b)
        _0x38b5d0 = _0x3b7479 % _0x5e9e9b
        _0x3b7479 = int((_0x3b7479 - _0x38b5d0) / _0x5e9e9b)
        _0x3a7eff = _0x3b7479 % _0x5e9e9b
        _0x27369a += _0x7c3dbb[_0x3a7eff] + _0x7c3dbb[_0x38b5d0] + _0x7c3dbb[_0x1da465] + dynamic_parameter
    return _0x27369a
​
​
print(get_md5_encrypt_str('9b6ed790af9bae4b109a79870590af51'))

前文提到,下图的这个值是会改变的:

29
29

我们来分析一下,这个值为什么会变,跟进到 _0x2a0d2b 函数中去,这里都是通过传一个整数和一个字符串,_0x2c3e() 就是个大数组,会变化,从数组中按索引取值然后计算得到最终的参数值,0x1c2 位置的值也并非固定的,数组和这个值都需要匹配出来:

30
30

_0x7ebea5(大数组) 以及一些值需要动态提取,这段代码简化后如下:

代码语言:javascript
复制
function _0x1497(_0x187038, _0x57dea3) {
    _0x7ebea5 = ["w3RcVeZcUG", "WPruWOZcQgu", "W741WO7cGCkw", "WOSBzhPY", "W78+WRNdM8oKuHpcImorWOOgWOa", "zmkojCkPja", "xCk4WRVcRce", "F0iPWR3cImkXAYRdV1pdKLC", "BvFdP2ldOW", "s8oSubiw", "WOD/W67cJSku", "WRJdNf1hW6tcNSoQ", "W5eaW414W5GRWPFdMG", "W4/dNtFcL8k/vCk6W5iaWRj8qG", "m8okEd9L", "WQ8SW6CsW6a", "CCk5W7xcVtO", "W7xdNLjHW5K", "imohcmkieq", "cmk7W49TEq", "WPvDCSoZW6u", "ChldUh4S", "WOVcS3tcKMi", "kf8Gdai", "mfjGWOFdNIe", "W6pcUqZdVmknW44", "k0vKWPm", "WQumW6ioW5a", "WOVcP8o3W5hdQ8oeEb4", "W7G+WPpcQSkD", "WQ1+W7/cUHnO", "DSklWQFdUM0", "WR4dE8kD", "qCozWPNcVCoY", "wmoQDSorWRK", "cSo/FqTr", "t8kqmSkIkG", "lxu9aXS", "EutcHmkGjW", "WOaCyKXC", "FmkEWOdcSXO", "aCoEomk5na", "W7lcVJ/cHCo8queWWOe", "Bd8oC8oc", "FCk6WQFcPHqf", "WQjuW5/cVmkg", "CNxdI8kXW6RcSW", "tvOZiu16W4VcVSouW4OgWPtcN8owpG", "lbFcUtJcUxLnW6OSW5rcWO7cTxNdQW", "W77dKg1iW4C", "WPn9WOtcK2m", "WPrKWRdcNre", "c8oyW6xdK8kY", "awS/gZW", "W6hcVrtdSSkEW4FdNg7dJW", "W7u/WRNdLCoKwWNcG8o1WOWmWRy", "CgxdN04+W5i", "WPSFBgTubGVdTSoXW4u", "qCkpW7rKWOPnWOm", "DSouzZal", "WPqeALT9", "WQ5vW6TmW5u", "WPnAuSozzeDjpbdcLmoD", "FrG8q8oSW6FdKtddGSku", "WQ1TWOFcGb8", "W6dcLsFdSmks", "W4hcIHRdUmk4", "lCozp8ozW4jZnSk8W5XQlCk7bW", "W7BdVJlcG8o+q0OSWQZcVmoeW69fWQLbWOTAW6i9WPRdK3BcKGv+qSonjq/dJtrLdmoGov3cVrpdTdr9EZq8DSk3fSotfqdcOW3cS8kLcvK9CsHNW6mlydGxWRxdRmoSwCoHWPbvW5OeWRFdQcqUW4/cVcxcI8kUDmofW43cJ10NdCovrbJcKWxdO8kWn8owWQ0nW6ZcHXeiWQ8wWP7cMSkbW6hcISo7W44PW78lWOymifNdKCoOnCkAzaWnhMq", "dmkEW7LSBG", "ACk7WPpcIHi", "WQNcVmkDwmoh", "FIijWRbh", "wCoaWPNcLSos", "W7uBWPLCW7y", "WR5LWOVcQgJcQK/dKrnd", "gmoXhmkmjmk8wG", "bcDOcgq", "BKFdQCkqW5G", "W5zuWQZcS2u6omkzWQFcSSocoq", "aCozW7VdV8kH", "WRnrumoZW7rAW65D", "DKZcI8kyhq", "WRrJWO7cV1pcIK0", "WQtcHuNdLSoD", "jCobqWHP", "DWmTw8oc", "WRdcJeBdVCoD", "WPHmWOtcLfS", "WQyCW5ykW7e", "WPfhWPpcNL0", "WPtcNwBdGq", "tfXIFdq5WQZdQG", "W60mfsLR", "vSkAWPtdH0NcVW", "xghdVCkrW6K", "W65fl8onW5dcGCo2iXDbWQ00", "tCorAWhcMxdcTSkuWPDtiCkiW7aSeSkdWRVcK8k/W7JcV8oJyxW2W5ldMNuFu8o0WP5nWRy0AG", "sv9SzGa+WRVdPq", "WRdcJwZdLSo1", "W6ZcLH/cTmoB", "WQLFWQhcLZq", "zSoRxW", "wCoJW7JdHmk6W4fm", "WRPcrmoJyq", "bmkOW75tDG", "jmk6bvLNWQBdPSorWQRdPCoLWQi", "WQdcMLxcO2m", "oCkWW5fIWPq", "WRmivSkXWQu", "WPrdW6VcQCkx", "W58QpYm", "W5SvWQHAW4m", "W5bFjtC8qetcUSkBWPGKka", "cmoRrIin", "w8ouWORcU8od", "gwjUWPtdKG", "tmooWP7cG8oCWPxcL8kMEmkkWO/dN8kuCf/cPdRdNSkJW4hdSqC3WQ3dPaPnWQXctLFdSmkbW7veW6ddUs4", "W7ZdPwH5W64", "W6vdkSolW5ZcH8oFhYH5WR4b", "iSoCW4FdOCkd", "uCk1W43cKX0", "WQdcPh3cGe0", "CKldPwZdOYe", "s8omrI4g", "zSkoWR3dTfi", "W6WnprXmW74SeSoBb8okWRP9CmkAW5L+WOVcMmktW4bzW5vwW4bDWQ7dJdq", "WQ94WOJcVgG", "eW9VDrCI", "nCkshMRdMG", "fSkOW6jwEW", "aJH8W6ldVq", "zwJcSGVcVqFcR3FcIG", "WRCbBSkxWP0", "WRf9W4pcOCkv", "t0JcMCkAdgZcPG", "WQuuF8kjWOFdMq", "u8k+WPJcNCoRWPLQnd5CdCoC", "WPXquSonzf0", "WRtcPNldVSo2", "W7q/WR3dN8oQuaRcSCoWWQCnWPu", "cXJcHmkcdNVcH8kp", "W6BdRcRdJtlcMGNdNc9IWP/dKq", "WO9ZWQFcGcaKs2y", "zCktWOFcJra", "WQfpW6VdOmoEWOS4CWRdPx/dNq", "CHuZvSoBW6a", "D1BdKSkfW78", "WPXFWRNcRMu", "aCoeW7ZdS8kI", "zLpdL1iq", "hNulWO1O", "WQD4W4P/W44", "WQubCSksWPa", "WQD/W53cOCki", "FSk6WP7cGYi", "d8odsbjR", "W7KAWRtcV8ktW5m", "fCkQkeldVW", "bSkuW5rRWOW", "WPdcP8kkr8oi", "WReKwN1K", "WPu5z8kDWO0", "s8oEWQtcGCo4WQtcG8kGsCoFWONdLG", "ecjpxs0", "b2mWWO9l", "F1FdU2FdRG", "WQxdSwnKW4S", "omoxoCkdiW", "haD8W4ldLSogtqZdSLBdGeFdRCkMCIywW6OMlmoVW7zAW7OzWOpcKSkEWPVcSq7dNCkZptP2qW1JAsfPW4VdPHbiq20vW6tdUhhcM0BcTqtdH8kfW4S5WORcHmoqW4BdHM5NvCkSW5VdJCowW6fqWQBdK13cHZ0HnapdJmkRWPtdQSkaWQbGpCoxkSkJW6dcVa", "WPu5t8k0WOS", "wCoEAraG", "smonWO3cVCow", "kxqHpG0", "WPZcTSkpvSot", "WQT/WQtcVN0", "tw7cQw3cIG", "W5JcTHFdLmk8", "W5m0W5ZdMNLKdIGZW6CjyW", "W7ZcJ2PEW5/cKmoefW", "WPbXWQ7cUbS", "jcjonwe", "xKlcH8kfgx3cTSkzWPDcWRG", "c2ldSxJdJrKjE8kBWP5h", "WQTrymoMW7jAW69u", "tvS1ivv4WOZdMmkIWPPVWQu", "WQZdJeniW7hcLmoGdG", "aSo8W43dJa", "W4BcJZxdV8kk", "w1FcGXRcQG", "D8oaymocWOjN", "WQP3W7JcH8kM", "WRhcI0NdHCoI", "DmkfW5JcVay", "lcTKqrm", "EmonB8oxWRvGymkLWQ1I", "mmo5vZWZ", "tSkNWRtdHfm", "F8oVWP7cJ8oD", "W5xcIc3dT8kS", "tCkwWQtdUfm", "f8kBW6XaWQi", "wSoCxISb", "wSkQbNDmWPbUW6ibbxHX", "uxVcKKBcVa", "WQ1iW4FcR8k7", "WRddVg9fW5i", "wCodWPJcMmojWQxcJmk1", "W6BcSGBdVSkbW6NdJG", "vYK7q8oH", "vCkbW6NcNW", "y8kyWQhdOf8", "W4W6WO3cVmkX", "uCogsay4", "f8kuW5XcWOe", "WQX4r8otW4C"];
    if (_0x187038 > 0x1c2){
        _0x187038 = _0x187038 - 0x1c2;
    }
    var _0x979086 = _0x7ebea5[_0x187038];
​
    var _0x18815a = function (_0x12f3cc) {
        var _0x4baee4 = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789+/=';
        var _0x34cff1 = ''
            , _0x32f5a8 = ''
            , _0x5720b1 = _0x34cff1 + _0x18815a;
        for (var _0x5baceb = 0x0, _0x464e32, _0x444df3, _0x286151 = 0x0; _0x444df3 = _0x12f3cc['charAt'](_0x286151++); ~_0x444df3 && (_0x464e32 = _0x5baceb % 0x4 ? _0x464e32 * 0x40 + _0x444df3 : _0x444df3,
        _0x5baceb++ % 0x4) ? _0x34cff1 += _0x5720b1['charCodeAt'](_0x286151 + 0xa) - 0xa !== 0x0 ? String['fromCharCode'](0xff & _0x464e32 >> (-0x2 * _0x5baceb & 0x6)) : _0x5baceb : 0x0) {
            _0x444df3 = _0x4baee4['indexOf'](_0x444df3);
        }
        for (var _0x2093c7 = 0x0, _0x3586f3 = _0x34cff1['length']; _0x2093c7 < _0x3586f3; _0x2093c7++) {
            _0x32f5a8 += '%' + ('00' + _0x34cff1['charCodeAt'](_0x2093c7)['toString'](0x10))['slice'](-0x2);
        }
        return decodeURIComponent(_0x32f5a8);
    };
    
    var _0x39e653 = function (_0x218a50, _0x1ead99) {
        var _0x4ec5dd = [], _0x568ad6 = 0x0, _0x4d9de0, _0x4a61ba = '';
        _0x218a50 = _0x18815a(_0x218a50);
        var _0x590931;
        for (_0x590931 = 0x0; _0x590931 < 0x100; _0x590931++) {
            _0x4ec5dd[_0x590931] = _0x590931;
        }
        for (_0x590931 = 0x0; _0x590931 < 0x100; _0x590931++) {
            _0x568ad6 = (_0x568ad6 + _0x4ec5dd[_0x590931] + _0x1ead99['charCodeAt'](_0x590931 % _0x1ead99['length'])) % 0x100,
                _0x4d9de0 = _0x4ec5dd[_0x590931],
                _0x4ec5dd[_0x590931] = _0x4ec5dd[_0x568ad6],
                _0x4ec5dd[_0x568ad6] = _0x4d9de0;
        }
        _0x590931 = 0x0,
            _0x568ad6 = 0x0;
        for (var _0x2312e7 = 0x0; _0x2312e7 < _0x218a50['length']; _0x2312e7++) {
            _0x590931 = (_0x590931 + 0x1) % 0x100,
                _0x568ad6 = (_0x568ad6 + _0x4ec5dd[_0x590931]) % 0x100,
                _0x4d9de0 = _0x4ec5dd[_0x590931],
                _0x4ec5dd[_0x590931] = _0x4ec5dd[_0x568ad6],
                _0x4ec5dd[_0x568ad6] = _0x4d9de0,
                _0x4a61ba += String['fromCharCode'](_0x218a50['charCodeAt'](_0x2312e7) ^ _0x4ec5dd[(_0x4ec5dd[_0x590931] + _0x4ec5dd[_0x568ad6]) % 0x100]);
        }
        return _0x4a61ba;
    };
​
    var _0x55e8a2 = _0x7ebea5[0x0]
        , _0x2a1bd8 = _0x187038 + _0x55e8a2;
​
    _0x979086 = _0x39e653(_0x979086, _0x57dea3);
    return _0x979086;
}
​
console.log(_0x1497(633, 'Wc%L'));

一般情况下,可以使用 AST 技术或者正则表达式,将上述动态变化的值匹配出来,然后传入到算法中,即可得到最终的结果:

31
31

_csrf 参数

跟到 '_csrf': _0x66ec8(_0x506031(0x1e8) + 'rf')[_0x370168(0x7a1)]() 中分析一下就会发现,_csrf 参数与 font_ident 参数一样,都是从网页源代码中获取到的:

32
32

至此,所有参数都分析完成了。

cookies 中有个参数值 seaut,如果该值或者加密参数不对,是无法获取到数据的(网页端的 cookies 可删除、修改参数值):

33
33

结果验证

原创声明:本文系作者授权腾讯云开发者社区发表,未经许可,不得转载。

如有侵权,请联系 cloudcommunity@tencent.com 删除。

原创声明:本文系作者授权腾讯云开发者社区发表,未经许可,不得转载。

如有侵权,请联系 cloudcommunity@tencent.com 删除。

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目录
  • 声明
  • 前言
  • 逆向目标
  • 逆向过程
    • 抓包分析
    • 逆向分析
      • keyword 参数
        • v 参数
          • font_ident
            • p 参数
              • _csrf 参数
              • 结果验证
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