First issue of JS reverse tutorial

JS The first issue of reverse tutorial

Project brief introduction

• This article is suitable for novice crawlers js Read in reverse , Preliminary contact JS reverse , Not very familiar with reverse operation , This article can be used as a reference , First step , If there's a big guy , Criticism and correction are also welcome
• This article takes Enterprise name Technology Take this website as an example , A preliminary introduction JS Reverse basic operation

Environmental preparation

• This project involves JS Debugging verification of , So there needs to be Chrome browser ,Nodejs（js Operating environment ）,WebStorm（IDE）
• nodejs Download and install it directly from the official website , After installation, enter node --version, If the version number appears, the installation is successful .
• WebStorm Activation is required after installation , There are many Baidu activation tutorials , Search by yourself , if necessary , You can also comment or send me a private letter to get the tutorial .

The analysis process

First , Go to the website https://www.qimingpian.cn/finosda/project/pinvestment：

View the source code ：

It's all js A file called , Data cannot be obtained directly through source code . Open developer tools , Carry out the bag , choice Fetch/XHR And documentation , To view the requests sent by the website ：

You can see that there is productListVip and industryFiledVip Two documents , Blind guess the first file is the tag list of the page , The second file is the company data of the page *-.-*, Click the first file and find that there is data encrypt_data, But it's encrypted data , So you need to js Document analysis ：

First , We can blindly guess that the data is the data we need , Then we can run for the purpose of decrypting the data js debugging ,

First , since js There is a code that encrypts the data in the file , Then there must be code to decrypt the data , Because at last, it will be displayed again html Come on , If not decrypted , How to display it ？

therefore , We can... Again source Find the... Used by the page in the panel js Code file ：

Choose what we need to debug js file , Check the source code of the previous page , We can choose first app.c68… This js File debugging , On the right side of the source code page “XHR/ Extract breakpoints ”, Its function is to request data on the page , Stop it . If the code is stacked on one line , You can click {} Format symbols .

We set up XHR The breakpoint ：

When the request data URL contains industryFiledVip Time is truncated , Refresh the page , You can find that debugging has started ：

We can keep going , If you find suspicious code , You can place the mouse over the variable to view the value of the variable ：

You can also output the value of this variable directly on the console ：

here , We debugged , You can locate suspicious data in the statement in the following figure ：

Output this parameter , View the data ：

You can find , This data seems to be what we need industryFiledVip In the document encrypt_data Parameters , At this point, our goal is very clear , Is to find the function that decrypts this parameter .

At this time, function call execution , Check the function called in this statement ：

At this time, we can see that there is a s(e) function , There are pairs json Code for parsing , At this time, we output this on the console s(e) The result of function execution ：

here , We can see it clearly , The return value of this function is the data we want , That is, the result of decrypting the previously encrypted data , So this function is internal o() The function must be used to decrypt encrypted data , And only one of the parameters is the result of function execution , The rest are written dead .

Now we turn it on WebStorm, Create a new one js file , Copy all the functions involved to js In file ：

The final will be entry_data Bring it into the function to perform the operation , You can get the data you want , You can proceed to the next step ：

thus , This time, it is relatively simple js Reverse is the end , Welcome to criticize and correct .（*.*)