js逆向实战之某市场监管公告服务平台返回数据解密

声明：本篇文章仅用于知识交流分享，不用于其他用途

练习网站：https://jzsc.mohurd.gov.cn/data/company

解密过程分析

访问网站，随便选择一个区域，点击查询，看触发哪些数据包。

只有一个数据包，且其响应数据一看就是经过加密的。
有经验的人就会条件反射是拦截器，全局搜索interceptors。

总共有7处，拦截器分为请求拦截器和响应拦截器，这里只需关注响应拦截器即可，有2处。

第二处相当于压栈的操作，所以这处就不用管了，重点看第一处。
打上断点，重新查询让其触发断点。
看到传进来的t变量的data属性值就是流量包中的响应数据，这段代码中跟t.data相关的代码只有一行var e = JSON.parse(b(t.data));，涉及到b函数，定位到b函数，打断点，让代码运行。
可以很明显的看到AES字样了，说明数据是经过AES加解密的，接下来我们只要搞清楚iv、mode和padding就可以解密了。一步一步往下执行，看每一行代码什么意思。
var e = d.a.enc.Hex.parse(t)：将t解析为一个WordArray对象
n = d.a.enc.Base64.stringify(e)：对上一步得到的e进行base64编码
```
a = d.a.AES.decrypt(n, f, {
  iv: m,
  mode: d.a.mode.CBC,
  padding: d.a.pad.Pkcs7
})
```
关键代码：n是需要解密的字符串，f是密钥，iv是偏移量、mode是aes解密的模式，padding是填充的方式，看看其对应的值分别是什么。
f = d.a.enc.Utf8.parse("jo8j9wGw%6HbxfFn")是个定值

m = d.a.enc.Utf8.parse("0123456789ABCDEF");是个定值

mode是CBC，padding是默认的Pkcs7，知道这些，那整个解密逻辑也就清楚了。
编写js代码。

var CryptoJS = require("crypto-js");

function decrypt(t) {
    var e = CryptoJS.enc.Hex.parse(t)
        , n = CryptoJS.enc.Base64.stringify(e)
        , a = CryptoJS.AES.decrypt(n, f, {
            iv: m,
            mode: CryptoJS.mode.CBC,
            padding: CryptoJS.pad.Pkcs7
        }),
        r = a.toString(CryptoJS.enc.Utf8);
    return r.toString()
}

f = {
    "words": [
        1148467306,
        964118391,
        624314466,
        2019968622
    ],
    "sigBytes": 16
};
m = {
    "words": [
        808530483,
        875902519,
        943276354,
        1128547654
    ],
    "sigBytes": 16
};

var t = "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console.log(decrypt(t));

运行结果如下：

这里有一点很奇怪，当我把f和m的值换成如下代码的时候就会一直报utf8编码错误的问题，不知该如何解决，希望有大佬能够解答。

代码如下：

function decrypt(t) {
    var e = CryptoJS.enc.Hex.parse(t)
        , f = CryptoJS.enc.Utf8.parse("jo8j9wGw%6HbxfFn")
        , m = CryptoJS.enc.Utf8.parse("0123456789ABCDEF")
        , n = CryptoJS.enc.Base64.stringify(e)
        , a = CryptoJS.AES.decrypt(n, f, {
            iv: m,
            mode: CryptoJS.mode.CBC,
            padding: CryptoJS.pad.Pkcs7
        }),
        r = a.toString(CryptoJS.enc.Utf8);
    return r.toString()
}

运行结果如下：

7. 编写python代码调用js代码实现数据的爬虫。

from functools import partial  # 锁定参数
import subprocess

subprocess.Popen = partial(subprocess.Popen, encoding="utf-8")

import requests
import execjs


url = "https://jzsc.mohurd.gov.cn/APi/webApi/dataservice/query/comp/list?qy_region=210200"
params = {"pg": 0, "pgsz": 15, "total": 0, }
headers = {"user-agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) "
                         "Chrome/130.0.0.0 Safari/537.36", "referer": "https://jzsc.mohurd.gov.cn/data/company",
           "accept": "application/json, text/plain, */*", "v": "231012"}

resp = requests.get(url, params=params, headers=headers)
file = open("decrypt.js", mode='r')
exec_js = file.read()
exec_code = execjs.compile(exec_js)
ming = exec_code.call("decrypt", resp.text)
print(ming)

运行结果如下：

与界面一致。

写完收工。

posted @ 2024-10-26 16:41 死不悔改奇男子阅读(60) 评论(0) 编辑收藏举报

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