Friday, March 29, 2024

FIN7 Hackers Using Weaponized Windows 11 Themed Word Document To Drop JavaScript Backdoor

Researchers uncovered a weaponized word document that mimics a malicious Windows 11 Alpha-theme used as a medium to drop a JavaScript payload with a JavaScript backdoor.

FIN7 is an APT threat group believed to reside in the Eastern European active since 2015, and this group considers as one of the notorious hacking groups targeted 100+ companies that involved with credit card theft of over 15 million payment card records that cost organizations around the world approximately one billion dollars (USD) in losses.

Researchers uncovered a weaponized word document that mimics a malicious Windows 11 Alpha-theme used as a medium to drop a JavaScript payload with a JavaScript backdoor.

FIN7 group operating with a different name including Carbon Spider, Gold Niagara, Calcium, also closely working with “Carbanak” another threat group that sharing TTP’s and their backdoor.

This group new come up with a new way of targeted attack by abusing the latest windows 11 update from Microsoft to inject a backdoor on the windows system using malicious Microsoft Word document (.doc) files.

Technical Analysis

The initial stage of the infection chain starts with an email phishing or spear-phishing campaign that contains a malicious Microsoft Word document (.doc) along with a decoy image posed as Windows 11 Alpha.

The image trick the victims to Enable Editing and Content to proceed to the next stage of the installation process, and the file embedded with the image contain a VBA macro. Once the victim enabled the content, then the Macro will be executed immediately.

Researchers from Anomali found a junk data is a common tactic used by threat actors to impede analysis. Once they remove this junk data, they are left with a VBA macro.

VBA Macro without Junk Data

Attackers also prevent the execution for some of the countries includes Russian, Ukrainian, Sorbian, Slovak, Slovenian, Estonian, Serbian, and if these languages are detected, the function me2XKr is called which deletes the table and stops running.

Also they are preventing the malware to execute on virtual machine and its stop the execution once its detected. Script also checks the following:-

  • Domain name, specifically CLEARMIND (Figure 9)
  • Language, if any of the languages listed in Table 1
  • Reg Key Language Preference for Russian
  • Virtual machine – VMWare, VirtualBox, innotek, QEMU, Oracle, Hyper and Parallels, if a VM is detected the script is killed (Figure 8)
  • Memory Available, if there is less than 4GB then don’t proceed
  • Check for RootDSE via LDAP

In-depth Analysis reveals an obfuscated strings, once replaced the obfuscated values with the deobfuscated strings, JavaScript backdoor functionalities are identified that are similar to the other FIN7 backdoors.

Finally, JavaScript backdoor is executed after connecting to the bypassociation[.]com address by checking the script for an active IP to retrieve the MAC address and DNSHostName.

“While not providing solid attribution, the language check function and table it scores against indicate a likely geographic location for the creator of this malicious doc file”. researchers said.

You can collect an IOC and malicious IP address here.

You can follow us on Linkedin, Twitter, Facebook for daily Cybersecurity and hacking news updates.

Website

Latest articles

IT and security Leaders Feel Ill-Equipped to Handle Emerging Threats: New Survey

A comprehensive survey conducted by Keeper Security, in partnership with TrendCandy Research, has shed...

How to Analyse .NET Malware? – Reverse Engineering Snake Keylogger

Utilizing sandbox analysis for behavioral, network, and process examination provides a foundation for reverse...

GoPlus’s Latest Report Highlights How Blockchain Communities Are Leveraging Critical API Security Data To Mitigate Web3 Threats

GoPlus Labs, the leading Web3 security infrastructure provider, has unveiled a groundbreaking report highlighting...

Wireshark 4.2.4 Released: What’s New!

Wireshark stands as the undisputed leader, offering unparalleled tools for troubleshooting, analysis, development, and...

Zoom Unveils AI-Powered All-In-One AI Work Workplace

Zoom has taken a monumental leap forward by introducing Zoom Workplace, an all-encompassing AI-powered...

iPhone Users Beware! Darcula Phishing Service Attacking Via iMessage

Phishing allows hackers to exploit human vulnerabilities and trick users into revealing sensitive information...
Balaji
Balaji
BALAJI is an Ex-Security Researcher (Threat Research Labs) at Comodo Cybersecurity. Editor-in-Chief & Co-Founder - Cyber Security News & GBHackers On Security.

Mitigating Vulnerability Types & 0-day Threats

Mitigating Vulnerability & 0-day Threats

Alert Fatigue that helps no one as security teams need to triage 100s of vulnerabilities.

  • The problem of vulnerability fatigue today
  • Difference between CVSS-specific vulnerability vs risk-based vulnerability
  • Evaluating vulnerabilities based on the business impact/risk
  • Automation to reduce alert fatigue and enhance security posture significantly

Related Articles