www.mcafee.com
Open in
urlscan Pro
104.70.95.190
Public Scan
URL:
https://www.mcafee.com/blogs/other-blogs/mcafee-labs/unmasking-asyncrat-new-infection-chain/
Submission: On November 09 via api from DE — Scanned from DE
Submission: On November 09 via api from DE — Scanned from DE
Form analysis 4 forms found in the DOM
https://www.mcafee.com/blogs
<form class="desktop-search-form-v2" action="https://www.mcafee.com/blogs">
<div><span class="search_icon_desktop"> <img src="/blogs/wp-content/themes/securingtomorrow-brillio/img/new-icons/search_icon_black.svg" alt="search grey icon"> </span></div>
<div class="desktop-search-div"><input class="dsk-search" autocomplete="off" name="s" type="text" placeholder="Search"></div>
</form>https://www.mcafee.com/blogs
<form class="desktop-search-form" style="display: none;" action="https://www.mcafee.com/blogs">
<div class="desktop-search-div"><input class="dsk-search" autocomplete="off" name="s" type="text" placeholder="Type and hit enter..."></div>
<div><span class="close_icon_desktop"> <img src="https://www.mcafee.com/blogs/wp-content/themes/securingtomorrow-brillio/img/new-icons/cross-grey-icon.svg" alt="close grey icon"> </span></div>
</form>https://www.mcafee.com/blogs
<form class="form-inline my-2 my-lg-0" action="https://www.mcafee.com/blogs">
<div class="input-group mb-3 search-div">
<div class="input-group-append"><button class="sarch-btn" type="button"><span class="fa fa-search" title="Type and hit enter..."><span style="display: none;">.</span></span> </button>
</div>
</div>
</form>https://www.mcafee.com/blogs
<form action="https://www.mcafee.com/blogs" class="desktop-search-form" style="display: none;">
<div class="desktop-search-div">
<input class="dsk-search" name="s" type="text" placeholder="Type and hit enter..." autocomplete="off">
</div>
<div><span class="close_icon_desktop">
<img src="https://www.mcafee.com/blogs/wp-content/themes/securingtomorrow-brillio/img/new-icons/cross-grey-icon.svg" alt="close grey icon">
</span>
</div>
</form>Text Content
* Products
* All-In-One Protection Recommended
* NEW!
McAfee+ Products
Worry-free protection for your privacy, identity and all your personal
devices.
Individual and family plans
* NEW!
McAfee+ Ultimate
Our most comprehensive privacy, identity and device protection with $2M
ID theft coverage.
* Total Protection
Protection for your devices with identity monitoring and VPN
* Device Protection
* Antivirus
* Virtual Private Network (VPN)
* Mobile Security
* Free Tools & Downloads
* Web Protection
* Free Antivirus Trial
* Device Security Scan
* Other Services
* PC Optimizer
* Techmaster Concierge
* Virus Removal
* Features
* Keep Me Private Online
* Personal Data Cleanup
* VPN (Virtual Private Network)
* Safeguard My Identity
* Identity Monitoring
* Security Freeze
* Identity Theft Coverage & Restoration
* Password Manager
* Protect My Devices
* Antivirus
* Web Protection
* Protect My Family
* Protection Score
* Parental Controls
* About Us
* Our Company
* Company Overview
* Awards & Reviews
* Investors
* Our Efforts
* Inclusion & Diversity
* Integrity & Ethics
* Public Policy
* Join Us
* Careers
* Life at McAfee
* Our Teams
* Our Locations
* Resources
* Stay Updated
* McAfee Blog
* Reports and Guides
* McAfee Labs
* McAfee on YouTube
* Learn More
* Learn at McAfee
* What is Antivirus?
* What is a VPN?
* What is Identity Theft?
* Press & News
* McAfee Newsroom
* Why McAfee
Products
Recommended
All-In-One Protection
NEW! McAfee+ Products
Worry-free protection for your privacy, identity and all your personal devices.
Individual and family plans
NEW! McAfee+ Ultimate
Our most comprehensive privacy, identity and device protection with $2M ID theft
coverage.
Total Protection
Protection for your devices with identity monitoring and VPN
Device Protection
Antivirus
Virtual Private Network (VPN)
Mobile Security
Free Tools & Downloads
Web Protection
Free Antivirus Trial
Device Security Scan
Other Services
PC Optimizer
Techmaster Concierge
Virus Removal
Features
Keep Me Private Online
Personal Data Cleanup
VPN (Virtual Private Network)
Safeguard My Identity
Identity Monitoring
Security Freeze
Identity Theft Coverage & Restoration
Password Manager
Protect My Devices
Antivirus
Web Protection
Protect My Family
Protection Score
Parental Controls
About Us
Our Company
Company Overview
Awards & Reviews
Investors
Our Efforts
Inclusion & Diversity
Integrity & Ethics
Public Policy
Join Us
Careers
Life at McAfee
Our Teams
Our Locations
Resources
Stay Updated
McAfee Blog
Reports and Guides
McAfee Labs
McAfee on YouTube
Learn More
Learn at McAfee
What is Antivirus?
What is a VPN?
What is Identity Theft?
Press & News
McAfee Newsroom
Why McAfee
Support
Help
Customer Support
Support Community
FAQs
Contact Us
Activation
Activate Retail Card
Choose Region
Sign in
* Support
* Help
* Customer Support
* Community
* FAQs
* Contact Us
* Activation
* Activate Retail Card
*
* Sign in
*
* Blog
* Topics
Internet Security Mobile Security Family Safety Privacy & Identity Protection
Security News Tips & Tricks
* At McAfee
McAfee News Executive Perspectives McAfee Labs Life at McAfee Hackable?
Podcast
* English
* Portuguese (BR)
* Spanish
* French(FR)
* German
* Italian
* Japanese
* French(CA)
* Portuguese (PT)
* Spanish (MX)
*
* Blog
* Topics
Internet Security Mobile Security Family Safety Privacy & Identity Protection
Security News Tips & Tricks
* At McAfee
McAfee News Executive Perspectives McAfee Labs Life at McAfee Hackable?
Podcast
* .
* Portuguese (BR) Spanish French(FR) German Italian Japanese French(CA)
Portuguese (PT) Spanish (MX)
Blog Other Blogs McAfee Labs Unmasking AsyncRAT New Infection Chain
UNMASKING ASYNCRAT NEW INFECTION CHAIN
McAfee Labs
Nov 03, 2023
7 MIN READ
Authored by Lakshya Mathur & Vignesh Dhatchanamoorthy
AsyncRAT, short for “Asynchronous Remote Access Trojan,” is a sophisticated
piece of malware designed to compromise the security of computer systems and
steal sensitive information. What sets AsyncRAT apart from other malware strains
is its stealthy nature, making it a formidable adversary in the world of
cybersecurity.
McAfee Labs has observed a recent AsyncRAT campaign being distributed through a
malicious HTML file. This entire infection strategy employs a range of file
types, including PowerShell, Windows Script File (WSF), VBScript (VBS), and
more, in order to bypass antivirus detection measures.
Figure 1 – AsyncRAT prevalence for the last one month
TECHNICAL ANALYSIS
A recipient receives a spam email containing a nefarious web link. When
accessed, this link triggers the download of an HTML file. Within this HTML
file, an ISO file is embedded, and this ISO image file harbors a WSF (Windows
Script File). The WSF file subsequently establishes connections with various
URLs and proceeds to execute multiple files in formats such as PowerShell, VBS
(VBScript), and BAT. These executed files are employed to carry out a process
injection into RegSvcs.exe, a legitimate Microsoft .NET utility. This
manipulation of RegSvcs.exe allows the attacker to covertly hide their
activities within a trusted system application.
Infection Chain
Figure 2 – Infection Chain
Stage 1: Analysis of HTML & WSF file
The sequence begins with a malicious URL found within the email, which initiates
the download of an HTML file. Inside this HTML file, an ISO file is embedded.
Further JavaScript is utilized to extract the ISO image file.
Figure 3 – Contents of HTML file
Figure 4 – Extracted ISO file when HTML is run
Within the ISO file is a WSF script labeled as
“FXM_20231606_9854298542_098.wsf.” This file incorporates junk strings of data,
interspersed with specific “<job>” and “<VBScript>” tags (as indicated in Figure
5 and highlighted in red). These tags are responsible for establishing a
connection to the URL “hxxp://45.12.253.107:222/f[.]txt” to fetch a PowerShell
file.
Figure 5 – Contents of WSF file
Stage 2: Analysis of PowerShell files
The URL “hxxp://45.12.253.107:222/f[.]txt” retrieves a text file that contains
PowerShell code.
Figure 6 – Contents of the First PowerShell file
The initial PowerShell code subsequently establishes a connection to another
URL, “hxxp://45.12.253.107:222/j[.]jpg,” and retrieves the second PowerShell
file.
Figure 7 – Contents of Second PowerShell file
The PowerShell script drops four files into the ProgramData folder, including
two PowerShell files, one VBS file, and one BAT file. The contents of these four
files are embedded within this PowerShell script. It then proceeds to create a
folder named “xral” in the ProgramData directory, where it writes and extracts
these files, as depicted in Figure 8.
Figure 8 – Second PowerShell creating 4 files and writing content in them using
[IO.File]::WriteAllText command
Figure 9 – Files extracted in the “ProgramData/xral” folder
Stage 3: Analysis of Files dropped in the ProgramData folder
Following this, the PowerShell script executes “xral.ps1,” which is responsible
for establishing a scheduled task to achieve persistence. Additionally, it
initiates the execution of the ” xral.vbs ” file.
Figure 10 – Content of VBS file
The VBS script proceeds to execute the “1.bat” file, which, in turn, is
responsible for executing the final PowerShell script, “hrlm.ps1.”
In a nutshell, after the second powershell, the execution goes like:
xral.ps1 -> xral.vbs -> 1.bat -> hrlm.ps1
These various executions of different file types are strategically employed to
circumvent both static and behavior-based antivirus detections.
Stage 4: Analysis of the final PowerShell file
Figure 11 – Content of final PowerShell file
As depicted in the preceding figure, this PowerShell file contains a PE
(Portable Executable) file in hexadecimal format. This file is intended for
injection into a legitimate process. In the second red-highlighted box, it’s
evident that the attackers have obfuscated the process name, which will be
revealed after performing a replacement operation. It is now evident that this
PE file is intended for injection into
“C:\Windows\Microsoft.NET\Framework\v4.0.30319\RegSvcs.exe.” The process
injection is accomplished through the Reflection Assembly load functionality of
the PowerShell file, which allows access and invocation of .NET data from within
PowerShell.
After the process injection, the RegSvcs utility is initiated and executed
without any additional parameters.
Stage 5: Analysis of infected RegSvcs.exe
Once PowerShell successfully injects malicious code into RegSvcs, the
compromised RegSvcs.exe runs, and the AsyncRAT server establishes a connection
to it. The artifacts of this infected RegSvcs.exe running are illustrated in
Figure 12.
Figure 12 – AsyncRAT server strings in RegSvcs
Further analysis uncovered that this sample possesses keylogging capabilities.
It recorded all activities performed on the system after replication, storing
this information in a “log.tmp” file within the TEMP folder for record-keeping
purposes.
Figure 13 – Log file created in %temp% folder logging all keystrokes
Furthermore, this sample was actively engaged in the theft of credentials and
browser-related data. Additionally, it attempted to search for
cryptocurrency-related information, including data related to Bitcoin, Ethereum,
and similar assets. The illicitly acquired data was being transmitted over TCP
to the IP address 45[.]12.253.107 on port 8808.
Figure 14 – TCP information of RegSvcs.exe
SUMMARY
The infection chain begins with a malicious URL embedded in a spam email,
leading to the download of an HTML file containing an ISO. Within the ISO file,
a WSF script connects to external URLs and downloads a PowerShell script, which,
in turn, initiates a series of non-PE file executions and ultimately injects a
hexadecimal-encoded PE file into the legitimate “RegSvcs.exe.” This compromised
process connects to an AsyncRAT server. The malware exhibits keylogging
capabilities, records user activities, and steals credentials, browser data, and
crypto-related information. Data is exfiltrated over TCP to an IP address and
port. This intricate chain leverages diverse file types and obfuscation methods
to avoid detection, ultimately resulting in the attackers gaining remote control
and successfully stealing data.
INDICATOR OF COMPROMISE (IOCS)
File SHA256/URL HTML
83c96c9853245a32042e45995ffa41393eeb9891e80ebcfb09de8fae8b5055a3 ISO
97f91122e541b38492ca2a7c781bb9f6b0a2e98e5b048ec291d98c273a6c3d62 WSF
ac6c6e196c9245cefbed223a3b02d16dd806523bba4e74ab1bcf55813cc5702a PS1
0159bd243221ef7c5f392bb43643a5f73660c03dc2f74e8ba50e4aaed6c6f531 PS1
f123c1df7d17d51115950734309644e05f3a74a5565c822f17c1ca22d62c3d99 PS1
19402c43b620b96c53b03b5bcfeaa0e645f0eff0bc6e9d1c78747fafbbaf1807 VBS
34cb840b44befdd236610f103ec1d0f914528f1f256d9ab375ad43ee2887d8ce BAT
1c3d5dea254506c5f7c714c0b05f6e2241a25373225a6a77929e4607eb934d08 PS1
83b29151a192f868362c0ecffe5c5fabe280c8baac335c79e8950fdd439e69ac URL
hxxp://45.12.253[.]107:222/f[.]txt hxxp://45.12.253[.]107:222/j[.]jpg
INTRODUCING MCAFEE+
Identity theft protection and privacy for your digital life
Download McAfee+ Now
Stay Updated
Follow us to stay updated on all things McAfee and on top of the latest consumer
and mobile security threats.
McAfee Labs Threat Research Team
McAfee Labs is one of the leading sources for threat research, threat
intelligence, and cybersecurity thought leadership. See our blog posts below for
more information.
MORE FROM MCAFEE LABS
Previous
CLOP RANSOMWARE EXPLOITS MOVEIT SOFTWARE
Authored by: Abhishek Karnik and Oliver Devane You may have heard recently in
the news that several...
Jun 21, 2023 | 3 MIN READ
GULOADER CAMPAIGNS: A DEEP DIVE ANALYSIS OF A HIGHLY EVASIVE SHELLCODE BASED
LOADER
Authored by: Anandeshwar Unnikrishnan Stage 1: GULoader Shellcode Deployment In
recent GULoader campaigns, we are seeing a...
May 09, 2023 | 22 MIN READ
NEW WAVE OF SHTML PHISHING ATTACKS
Authored By Anuradha McAfee Labs has recently observed a new wave of phishing
attacks. In this wave,...
May 08, 2023 | 5 MIN READ
DECONSTRUCTING AMADEY’S LATEST MULTI-STAGE ATTACK AND MALWARE DISTRIBUTION
Authored by By Yashvi Shah McAfee Labs have identified an increase in
Wextract.exe samples, that drop a...
May 05, 2023 | 17 MIN READ
EXPLORING WINRAR VULNERABILITY (CVE-2023-38831)
Authored by Neil Tyagi On 23 August 2023, NIST disclosed a critical RCE
vulnerability CVE-2023-38831. It is...
Sep 19, 2023 | 8 MIN READ
AGENT TESLA’S UNIQUE APPROACH: VBS AND STEGANOGRAPHY FOR DELIVERY AND INTRUSION
Authored by Yashvi Shah Agent Tesla functions as a Remote Access Trojan (RAT)
and an information stealer...
Sep 08, 2023 | 13 MIN READ
PEELING BACK THE LAYERS OF REMCOSRAT MALWARE
Authored by Preksha Saxena McAfee labs observed a Remcos RAT campaign where
malicious VBS files were delivered...
Aug 29, 2023 | 9 MIN READ
CRYPTO SCAM: SPACEX TOKENS FOR SALE
Authored by: Neil Tyagi Scam artists know no bounds—and that also applies to
stealing your cryptocurrency. Crypto...
Aug 24, 2023 | 5 MIN READ
INVISIBLE ADWARE: UNVEILING AD FRAUD TARGETING ANDROID USERS
Authored by SangRyol Ryu, McAfee Threat Researcher We live in a world where
advertisements are everywhere, and...
Aug 04, 2023 | 6 MIN READ
THE SEASON OF BACK TO SCHOOL SCAMS
Authored by: Lakshya Mathur and Yashvi Shah As the Back-to-School season
approaches, scammers are taking advantage of...
Aug 02, 2023 | 5 MIN READ
SCAMMERS FOLLOW THE REBRANDING OF TWITTER TO X, TO DISTRIBUTE MALWARE
Authored by: Vallabh Chole and Yerko Grbic On July 23rd, 2023, Elon Musk
announced that the social...
Jul 25, 2023 | 3 MIN READ
ANDROID SPYNOTE ATTACKS ELECTRIC AND WATER PUBLIC UTILITY USERS IN JAPAN
Authored by Yukihiro Okutomi McAfee’s Mobile team observed a smishing campaign
against Japanese Android users posing as...
Jul 21, 2023 | 5 MIN READ
CLOP RANSOMWARE EXPLOITS MOVEIT SOFTWARE
Authored by: Abhishek Karnik and Oliver Devane You may have heard recently in
the news that several...
Jun 21, 2023 | 3 MIN READ
GULOADER CAMPAIGNS: A DEEP DIVE ANALYSIS OF A HIGHLY EVASIVE SHELLCODE BASED
LOADER
Authored by: Anandeshwar Unnikrishnan Stage 1: GULoader Shellcode Deployment In
recent GULoader campaigns, we are seeing a...
May 09, 2023 | 22 MIN READ
NEW WAVE OF SHTML PHISHING ATTACKS
Authored By Anuradha McAfee Labs has recently observed a new wave of phishing
attacks. In this wave,...
May 08, 2023 | 5 MIN READ
DECONSTRUCTING AMADEY’S LATEST MULTI-STAGE ATTACK AND MALWARE DISTRIBUTION
Authored by By Yashvi Shah McAfee Labs have identified an increase in
Wextract.exe samples, that drop a...
May 05, 2023 | 17 MIN READ
EXPLORING WINRAR VULNERABILITY (CVE-2023-38831)
Authored by Neil Tyagi On 23 August 2023, NIST disclosed a critical RCE
vulnerability CVE-2023-38831. It is...
Sep 19, 2023 | 8 MIN READ
AGENT TESLA’S UNIQUE APPROACH: VBS AND STEGANOGRAPHY FOR DELIVERY AND INTRUSION
Authored by Yashvi Shah Agent Tesla functions as a Remote Access Trojan (RAT)
and an information stealer...
Sep 08, 2023 | 13 MIN READ
PEELING BACK THE LAYERS OF REMCOSRAT MALWARE
Authored by Preksha Saxena McAfee labs observed a Remcos RAT campaign where
malicious VBS files were delivered...
Aug 29, 2023 | 9 MIN READ
CRYPTO SCAM: SPACEX TOKENS FOR SALE
Authored by: Neil Tyagi Scam artists know no bounds—and that also applies to
stealing your cryptocurrency. Crypto...
Aug 24, 2023 | 5 MIN READ
INVISIBLE ADWARE: UNVEILING AD FRAUD TARGETING ANDROID USERS
Authored by SangRyol Ryu, McAfee Threat Researcher We live in a world where
advertisements are everywhere, and...
Aug 04, 2023 | 6 MIN READ
THE SEASON OF BACK TO SCHOOL SCAMS
Authored by: Lakshya Mathur and Yashvi Shah As the Back-to-School season
approaches, scammers are taking advantage of...
Aug 02, 2023 | 5 MIN READ
SCAMMERS FOLLOW THE REBRANDING OF TWITTER TO X, TO DISTRIBUTE MALWARE
Authored by: Vallabh Chole and Yerko Grbic On July 23rd, 2023, Elon Musk
announced that the social...
Jul 25, 2023 | 3 MIN READ
ANDROID SPYNOTE ATTACKS ELECTRIC AND WATER PUBLIC UTILITY USERS IN JAPAN
Authored by Yukihiro Okutomi McAfee’s Mobile team observed a smishing campaign
against Japanese Android users posing as...
Jul 21, 2023 | 5 MIN READ
CLOP RANSOMWARE EXPLOITS MOVEIT SOFTWARE
Authored by: Abhishek Karnik and Oliver Devane You may have heard recently in
the news that several...
Jun 21, 2023 | 3 MIN READ
GULOADER CAMPAIGNS: A DEEP DIVE ANALYSIS OF A HIGHLY EVASIVE SHELLCODE BASED
LOADER
Authored by: Anandeshwar Unnikrishnan Stage 1: GULoader Shellcode Deployment In
recent GULoader campaigns, we are seeing a...
May 09, 2023 | 22 MIN READ
NEW WAVE OF SHTML PHISHING ATTACKS
Authored By Anuradha McAfee Labs has recently observed a new wave of phishing
attacks. In this wave,...
May 08, 2023 | 5 MIN READ
DECONSTRUCTING AMADEY’S LATEST MULTI-STAGE ATTACK AND MALWARE DISTRIBUTION
Authored by By Yashvi Shah McAfee Labs have identified an increase in
Wextract.exe samples, that drop a...
May 05, 2023 | 17 MIN READ
Next
* 1
* 2
* 3
Back to top
*
*
*
*
*
--------------------------------------------------------------------------------
Corporate Headquarters
6220 America Center Drive
San Jose, CA 95002 USA
Products
McAfee+
McAfee® Total Protection
McAfee Antivirus
McAfee Safe Connect
McAfee PC Optimizer
McAfee Techmaster
McAfee Mobile Security
Resources
Antivirus
Free Downloads
Parental Controls
Malware
Firewall
Blogs
Activate Retail Card
McAfee Labs
Support
Customer Support
FAQs
Renewals
Support Community
About
About McAfee
Careers
Contact Us
Newsroom
Investors
Legal Terms
Your Privacy Choices
System Requirements
Sitemap
--------------------------------------------------------------------------------
United States / English Copyright © 2023 McAfee, LLC
United States / English Copyright © 2023 McAfee, LLC
✓
Thanks for sharing!
AddToAny
More…