【自执行闭包JS逆向】某网站登录MD5加密分析

一、写在前面

   最近工作比较忙，不过还是在督促自己利用有限的时间学习更新一些技术文章。互联网这个行业大家目前也都知道是非常内卷的，所有大家在工作之余养成良好的自主学习习惯是非常好的，多的就不说了，开始本期重点！

分析站点：

aHR0cHM6Ly9pLmZrdy5jb20v

在开始之前这里说一下“自执行”和“闭包”。它们概念相似，但不完全相同。自执行函数是一种函数，它在定义之后会立即执行，通常使用 (function() { /* code */ })(); 这种形式。闭包是一个更广泛的概念，它指的是一个函数能够访问并保存在其外部定义的变量的能力

二、抓包分析

  这次分析的还是登陆参数，加密的对象是密码pwd。大家一定记得看看我之前写的这篇文章：JS逆向中快速搜索定位加密函数技巧总结

这里我们简单构造一个用户名密码进行登录抓包分析，密码就123456（MD5加密的话16位以49开头、32位e10或E10开头）

老规矩这里我们可以搜索pwd或者我们已经猜到加密方式，根据我上面文章的各个密码特征关键词搜索都是可以的：

像我上面所示，根据MD5加密算法的关键词1732584193进行搜索也能够快速定位到加密函数位置！

同样也可以搜索pwd或者断点方式调式找到加密加密位置，发现md5鼠标点击跳转到加密函数

三、加密函数分析

  通过下图我们可以看到md5加密函数是一个自执行闭包函数，这里我们将*jQuery这部分稍微修改一下，无需引入 jQuery，修改加密JS代码如下：

(function(g) {function o(u, z) {var w = (u & 65535) + (z & 65535), v = (u >> 16) + (z >> 16) + (w >> 16);return (v << 16) | (w & 65535)}function s(u, v) {return (u << v) | (u >>> (32 - v))}function c(A, w, v, u, z, y) {return o(s(o(o(w, A), o(u, y)), z), v)}function b(w, v, B, A, u, z, y) {return c((v & B) | ((~v) & A), w, v, u, z, y)}function i(w, v, B, A, u, z, y) {return c((v & A) | (B & (~A)), w, v, u, z, y)}function n(w, v, B, A, u, z, y) {return c(v ^ B ^ A, w, v, u, z, y)}function a(w, v, B, A, u, z, y) {return c(B ^ (v | (~A)), w, v, u, z, y)}function d(F, A) {F[A >> 5] |= 128 << ((A) % 32);F[(((A + 64) >>> 9) << 4) + 14] = A;var w, z, y, v, u, E = 1732584193, D = -271733879, C = -1732584194, B = 271733878;for (w = 0; w < F.length; w += 16) {z = E;y = D;v = C;u = B;E = b(E, D, C, B, F[w], 7, -680876936);B = b(B, E, D, C, F[w + 1], 12, -389564586);C = b(C, B, E, D, F[w + 2], 17, 606105819);D = b(D, C, B, E, F[w + 3], 22, -1044525330);E = b(E, D, C, B, F[w + 4], 7, -176418897);B = b(B, E, D, C, F[w + 5], 12, 1200080426);C = b(C, B, E, D, F[w + 6], 17, -1473231341);D = b(D, C, B, E, F[w + 7], 22, -45705983);E = b(E, D, C, B, F[w + 8], 7, 1770035416);B = b(B, E, D, C, F[w + 9], 12, -1958414417);C = b(C, B, E, D, F[w + 10], 17, -42063);D = b(D, C, B, E, F[w + 11], 22, -1990404162);E = b(E, D, C, B, F[w + 12], 7, 1804603682);B = b(B, E, D, C, F[w + 13], 12, -40341101);C = b(C, B, E, D, F[w + 14], 17, -1502002290);D = b(D, C, B, E, F[w + 15], 22, 1236535329);E = i(E, D, C, B, F[w + 1], 5, -165796510);B = i(B, E, D, C, F[w + 6], 9, -1069501632);C = i(C, B, E, D, F[w + 11], 14, 643717713);D = i(D, C, B, E, F[w], 20, -373897302);E = i(E, D, C, B, F[w + 5], 5, -701558691);B = i(B, E, D, C, F[w + 10], 9, 38016083);C = i(C, B, E, D, F[w + 15], 14, -660478335);D = i(D, C, B, E, F[w + 4], 20, -405537848);E = i(E, D, C, B, F[w + 9], 5, 568446438);B = i(B, E, D, C, F[w + 14], 9, -1019803690);C = i(C, B, E, D, F[w + 3], 14, -187363961);D = i(D, C, B, E, F[w + 8], 20, 1163531501);E = i(E, D, C, B, F[w + 13], 5, -1444681467);B = i(B, E, D, C, F[w + 2], 9, -51403784);C = i(C, B, E, D, F[w + 7], 14, 1735328473);D = i(D, C, B, E, F[w + 12], 20, -1926607734);E = n(E, D, C, B, F[w + 5], 4, -378558);B = n(B, E, D, C, F[w + 8], 11, -2022574463);C = n(C, B, E, D, F[w + 11], 16, 1839030562);D = n(D, C, B, E, F[w + 14], 23, -35309556);E = n(E, D, C, B, F[w + 1], 4, -1530992060);B = n(B, E, D, C, F[w + 4], 11, 1272893353);C = n(C, B, E, D, F[w + 7], 16, -155497632);D = n(D, C, B, E, F[w + 10], 23, -1094730640);E = n(E, D, C, B, F[w + 13], 4, 681279174);B = n(B, E, D, C, F[w], 11, -358537222);C = n(C, B, E, D, F[w + 3], 16, -722521979);D = n(D, C, B, E, F[w + 6], 23, 76029189);E = n(E, D, C, B, F[w + 9], 4, -640364487);B = n(B, E, D, C, F[w + 12], 11, -421815835);C = n(C, B, E, D, F[w + 15], 16, 530742520);D = n(D, C, B, E, F[w + 2], 23, -995338651);E = a(E, D, C, B, F[w], 6, -198630844);B = a(B, E, D, C, F[w + 7], 10, 1126891415);C = a(C, B, E, D, F[w + 14], 15, -1416354905);D = a(D, C, B, E, F[w + 5], 21, -57434055);E = a(E, D, C, B, F[w + 12], 6, 1700485571);B = a(B, E, D, C, F[w + 3], 10, -1894986606);C = a(C, B, E, D, F[w + 10], 15, -1051523);D = a(D, C, B, E, F[w + 1], 21, -2054922799);E = a(E, D, C, B, F[w + 8], 6, 1873313359);B = a(B, E, D, C, F[w + 15], 10, -30611744);C = a(C, B, E, D, F[w + 6], 15, -1560198380);D = a(D, C, B, E, F[w + 13], 21, 1309151649);E = a(E, D, C, B, F[w + 4], 6, -145523070);B = a(B, E, D, C, F[w + 11], 10, -1120210379);C = a(C, B, E, D, F[w + 2], 15, 718787259);D = a(D, C, B, E, F[w + 9], 21, -343485551);E = o(E, z);D = o(D, y);C = o(C, v);B = o(B, u)}return [E, D, C, B]}function p(v) {var w, u = "";for (w = 0; w < v.length * 32; w += 8) {u += String.fromCharCode((v[w >> 5] >>> (w % 32)) & 255)}return u}function j(v) {var w, u = [];u[(v.length >> 2) - 1] = undefined;for (w = 0; w < u.length; w += 1) {u[w] = 0}for (w = 0; w < v.length * 8; w += 8) {u[w >> 5] |= (v.charCodeAt(w / 8) & 255) << (w % 32)}return u}function k(u) {return p(d(j(u), u.length * 8))}function f(w, z) {var v, y = j(w), u = [], x = [], A;u[15] = x[15] = undefined;if (y.length > 16) {y = d(y, w.length * 8)}for (v = 0; v < 16; v += 1) {u[v] = y[v] ^ 909522486;x[v] = y[v] ^ 1549556828}A = d(u.concat(j(z)), 512 + z.length * 8);return p(d(x.concat(A), 512 + 128))}function t(w) {var z = "0123456789abcdef", v = "", u, y;for (y = 0; y < w.length; y += 1) {u = w.charCodeAt(y);v += z.charAt((u >>> 4) & 15) + z.charAt(u & 15)}return v}function m(u) {return unescape(encodeURIComponent(u))}function q(u) {return k(m(u))}function l(u) {return t(q(u))}function h(u, v) {return f(m(u), m(v))}function r(u, v) {return t(h(u, v))}g.md5 = function(v, w, u) {if (!w) {if (!u) {return l(v);} else {return q(v);}}if (!u) {return r(w, v);} else {return h(w, v);}}
}(typeof window !== "undefined" ? window : this));

最后我们使用JS调试工具就能验证了，这里我直接在控制台把扣出来的JS加密函数贴进去调用测试如下：

  好了，到这里又到了跟大家说再见的时候了。创作不易，帮忙点个赞再走吧。你的支持是我创作的动力，希望能带给大家更多优质的文章