爬虫反爬：JS逆向之某东参数

科技 08-02 来源：阿呆攻防

简介

从上面两节实战中已经可以做一个属于自己的翻译应用了，甚至可以对翻译结果进行对比然后通过一些语意软件进行优化，这里的所有的DEMO都只是为了学习JS逆向这些技能的过程，今天这节是关于某东登陆参数的逆向，只是为了巩固调试技巧，在实际操作上也不能直接登陆，因为还有一个滑块验证，这个后期再学习。

实战信息

网址：

aHR0cHM6Ly9wYXNzcG9ydC5qZC5jb20vbmV3L2xvZ2luLmFzcHg=

接口：

aHR0cHM6Ly9wYXNzcG9ydC5qZC5jb20vdWMvbG9naW5TZXJ2aWNlP3V1aWQ9NTMzZGJiN2MtNzQ3Yi00MzhmLTgwOGUtZWNiOTRkNzhjM2FiJiZyPTAuNTg0MzU4NzYxMDE0ODc0NCZ2ZXJzaW9uPTIwMTU=

逆向参数：

- uuid

- eid

- fp

- nloginpwd

- authcode

- pubKey

- sa_token

- seqSid

实战流程

一、找接口

点击登陆通过按F12打开控制台的network找到发请求的包。这里由于有个参数是通过页面加载时发送的一个请求获取的，建议在打开控制台后刷新页面重新抓包加载。

二、下断点

首先肯定先测试XHR断点，因为XHR可以快速断到函数的调用栈，从栈中往上找即可。

通过"/uc/loginService"可以直接断住。

看函数名称就可以知道是"loginSubmit"，所以我们可以直接打过去查看传参位置。

可以看到uuid、eid、fp、pubKey、sa_token是直接.val()获取的，从这里可以看出调用的是jQuey的input文本框里面的属性值，但是我们没有从界面上看到，所以他肯定是，所以可以直接去html中找到，直接搜索即可。nloginpwd参数使用了加密方法getEntryptPwd()，seqSid参数是通过window中的属性拿到的。

我们首先在页面中找到这些参数，直接搜索"f8....."这些具体数据即可。

所以在login.aspx中可以直接在input的value的属性中找到。

然后去找nloginpwd参数的调用方法，然后抠下来去本地运行即可。

function getEntryptPwd(pwd){      var pubKey = $('#pubKey').val();      if(!pwd || !pubKey || !SysConfig.encryptInfo){          return pwd;      }      var encrypt = new JSEncrypt();      encrypt.setPublicKey(pubKey);      return encrypt.encrypt(pwd);  }

这里可以看到$('#pubKey').val()就是获取html公钥所以抠下来的代码需要替换掉，可以抠下测试代码来，这里需要一些本地Navigator还有Window这些对象环境，所以直接放到Snippets上运行。

debug运行结果：

Snippets面板结果：

最后寻找seqSid这个参数是从window._jdtdmap_sessionId中来，我们首先搜索一下里面的值"351931498402249129"。

从这里也可以看到_jdtdmap_sessionId的值是写死的，但是在这段代码里没看到加入到window中，所以我们直接搜索_jdtdmap_sessionId，去寻找哪里加入到window中或者是否被处理。

在排除完后发现只有这段混淆的代码疑似可能是放到window对象中的代码。

看到代码的最前部分是由eval()方法独立运行的，创建一个vm的方式那就是可以直接全抠。

window.a1 = function(p, a, c, k, e, r) {    e = function(c) {        return (c < a ? '' : e(parseInt(c / a))) + ((c = c % a) > 35 ? String.fromCharCode(c + 29) : c.toString(36))    }    ;    if (!''.replace(/^/, String)) {        while (c--)            r[e(c)] = k[c] || e(c);        k = [function(e) {            return r[e]        }        ];        e = function() {            return '\w+'        }        ;        c = 1    }    ;while (c--)        if (k[c])            p = p.replace(new RegExp('\b' + e(c) + '\b','g'), k[c]);    return p}

抠出方法来改写运行将自执行的参数填入，最后在控制台运行得到混淆前的代码。

最后得到这段字符串代码。

(function(){var m=["clstag","id","tdtag","class"],u=0,v="",w="click blur focus change scroll input keydown keypress keyup".split(" "),x="onclick onblur onfocus onchange onscroll onpropertychange onkeydown onkeypress onkeyup".split(" "),A=("https:"==document.location.protocol?"https://":"http://")+"seq.jd.com/jseq.html",k="click input change focus blur scroll keydown keypress keyup sniffV sniffL".split(" "),B={49:"a",50:"a",51:"a",52:"a",53:"a",54:"a",55:"a",56:"a",57:"a",48:"a",96:"a",97:"a",98:"a",99:"a",100:"a",101:"a",102:"a",103:"a",104:"a",105:"a",81:"b",87:"b",69:"b",82:"b",84:"b",89:"b",85:"b",73:"b",79:"b",80:"b",65:"b",83:"b",68:"b",70:"b",71:"b",90:"b",88:"b",72:"b",74:"b",75:"b",76:"b",67:"b",86:"b",66:"b",78:"b",77:"b",192:"c",189:"c",187:"c",219:"c",221:"c",220:"c",186:"c",222:"c",188:"c",190:"c",191:"c",111:"c",106:"c",109:"c",107:"c",110:"c",32:"c"};this.init=function(){if(!("undefined"==typeof _jdtdseq_config_data||null==_jdtdseq_config_data||0>=_jdtdseq_config_data.length)){var a=_jdtdseq_config_data.bizId;globalUnixstamp(a);scrollSeq(window,joinReturnObj(null,null,a,"0",k[5]));for(var b=_jdtdseq_config_data.seqs,e=0;e>Math.round(((19<<43)/90^34)/214);h=(h&3)<<4|f>>4;var l=(f&15)<<2|e>>6;c=e&Math.round(((19<<43)/90^34)/6)-4;isNaN(f)?l=c=Math.round(((19<<43)/90^34)/6)-3:isNaN(e)&&(c=Math.round(((19<<43)/90^34)/6)-3);g=g+b.charAt(k)+b.charAt(h)+b.charAt(l)+b.charAt(c);k=h=l=c=h=f=e=""}while(d<=a.length);return g+"/"},C=function(a){if(void 0==a||null==a)return null;var b="{",e;for(e in a)b+="'"+e+"':",b="string"==typeof a[e]?b+("'"+a[e]+"'"):b+a[e],b+=",";b=b.substring(0,b.length-1);return E(b+"}")},r=function(a){var b=B[a];return b?b:a};this.init()})();

格式化后运行看一下是否有window._jdtdmap_sessionId｜window['_jdtdmap_sessionId']｜window["_jdtdmap_sessionId"]有就说明是成功的，因为是自执行里面必须会有window对象。

(function () {    var m = ["clstag", "id", "tdtag", "class"], u = 0, v = "",        w = "click blur focus change scroll input keydown keypress keyup".split(" "),        x = "onclick onblur onfocus onchange onscroll onpropertychange onkeydown onkeypress onkeyup".split(" "),        A = ("https:" == document.location.protocol ? "https://" : "http://") + "seq.jd.com/jseq.html",        k = "click input change focus blur scroll keydown keypress keyup sniffV sniffL".split(" "), B = {            49: "a",            50: "a",            51: "a",            52: "a",            53: "a",            54: "a",            55: "a",            56: "a",            57: "a",            48: "a",            96: "a",            97: "a",            98: "a",            99: "a",            100: "a",            101: "a",            102: "a",            103: "a",            104: "a",            105: "a",            81: "b",            87: "b",            69: "b",            82: "b",            84: "b",            89: "b",            85: "b",            73: "b",            79: "b",            80: "b",            65: "b",            83: "b",            68: "b",            70: "b",            71: "b",            90: "b",            88: "b",            72: "b",            74: "b",            75: "b",            76: "b",            67: "b",            86: "b",            66: "b",            78: "b",            77: "b",            192: "c",            189: "c",            187: "c",            219: "c",            221: "c",            220: "c",            186: "c",            222: "c",            188: "c",            190: "c",            191: "c",            111: "c",            106: "c",            109: "c",            107: "c",            110: "c",            32: "c"        };    this.init = function () {        if (!("undefined" == typeof _jdtdseq_config_data || null == _jdtdseq_config_data || 0 >= _jdtdseq_config_data.length)) {            var a = _jdtdseq_config_data.bizId;            globalUnixstamp(a);            scrollSeq(window, joinReturnObj(null, null, a, "0", k[5]));            for (var b = _jdtdseq_config_data.seqs, e = 0; e < b.length; e++) {                var c = b[e];                var d = null;                var g = c.selVal;                switch (c.selType) {                    case m[0]:                        d = y("[" + m[0] + "='" + g + "']")[0];                        break;                    case m[1]:                        d = document.getElementById(g);                        break;                    case m[2]:                        d = y("[" + m[2] + "='" + g + "']")[0];                        break;                    case m[3]:                        d = g;                        if (document.getElementsByClassName) d = document.getElementsByClassName(d); else {                            g = document.getElementsByTagName("*");                            for (var h = [], f = 0; f < g.length; f++) for (var z = g[f], q = z.className.split(" "), p = 0; p < q.length; p++) if (q[p] == d) {                                h.push(z);                                break                            }                            d = h                        }                        d = d[0]                }                if (null != d && void 0 != d) for (g = 0; g < c.seq.length; g++) switch (h = c.seq[g], f = {}, f.bizId = a, f.elementId = c.elementId, f.seq = h, f.sessionId = _jdtdmap_sessionId, f.special = c.special, h) {                    case k[0]:                        clickCount(d, f);                        break;                    case k[1]:                        inputEvent(d, f);                        break;                    case k[2]:                        changeEvent(d, f);                        break;                    case k[3]:                        focusEvent(d, f);                        break;                    case k[4]:                        blurEvent(d, f);                        break;                    case k[5]:                        scrollSeq(d, f);                        break;                    case k[6]:                        keyDownEvent(d, f);                        break;                    case k[7]:                        keyPressEvent(d, f);                        break;                    case k[8]:                        keyUpEvent(d, f);                        break;                    case k[9]:                        sniffV(d, f);                        break;                    case k[10]:                        sniffL(d, f)                }            }        }    };    this.globalUnixstamp = function (a) {        var b = joinReturnObj(null, "1", a, "0", k[3]);        n(b);        l(window, 2, function () {            return joinReturnObj(null, "1", a, "0", k[3])        });        l(window, 1, function () {            return joinReturnObj(null, "1", a, "0", k[4])        })    };    this.clickCount = function (a, b) {        l(a, 0, function () {            return b = joinReturnObj(b, "1")        })    };    this.focusEvent = function (a, b) {        l(a, 2, function () {            return b = joinReturnObj(b, "1")        })    };    this.blurEvent = function (a, b) {        l(a, 1, function () {            return b = joinReturnObj(b, "1")        })    };    this.changeEvent = function (a, b) {        l(a, 3, function () {            return b = joinReturnObj(b, a.value.length)        })    };    this.inputEvent = function (a, b) {        l(a, 5, function () {            return b = joinReturnObj(b, a.value.length)        })    };    this.scrollSeq = function (a, b) {        l(a, 4, function () {            return b = joinReturnObj(b, document.documentElement.scrollTop || document.body.scrollTop)        })    };    this.keyDownEvent = function (a, b) {        l(a, 6, function (a, c) {            c = c || window.event;            a = c.keyCode && 0 < c.keyCode ? c.keyCode : c.which;            a = "undefined" == typeof a ? c.charCode : a;            "1" == b.special && (a = r(a));            return joinReturnObj(b, a)        })    };    this.keyPressEvent = function (a, b) {        l(a, 7, function (a, c) {            c = c || window.event;            a = c.keyCode && 0 < c.keyCode ? c.keyCode : c.which;            a = "undefined" == typeof a ? c.charCode : a;            "1" == b.special && (a = r(a));            return joinReturnObj(b, a)        })    };    this.keyUpEvent = function (a, b) {        l(a, 8, function (a, c) {            c = c || window.event;            a = c.keyCode && 0 < c.keyCode ? c.keyCode : c.which;            a = "undefined" == typeof a ? c.charCode : a;            "1" == b.special && (a = r(a));            return joinReturnObj(b, a)        })    };    this.sniffV = function (a, b) {        a = a ? a.value : "unknow";        commonFn();        b = joinReturnObj(b, a);        n(b)    };    this.sniffL = function (a, b) {        function e(b) {            b = b || event; 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