www.trendmicro.com Open in urlscan Pro
23.32.242.31  Public Scan

URL: https://www.trendmicro.com/en_us/research/23/k/parasitesnatcher-how-malicious-chrome-extensions-target-brazil-.html?&web_vi...
Submission: On November 27 via api from DE — Scanned from DE

Form analysis 1 forms found in the DOM

<form class="main-menu-search" aria-label="Search Trend Micro" data-equally-id="equally_ai___gQNBS">
  <div class="main-menu-search__field-wrapper" id="cludo-search-form">
    <table class="gsc-search-box">
      <tbody>
        <tr>
          <td class="gsc-input">
            <input type="text" class="gsc-input-field" name="search" title="search" placeholder="Search" autocomplete="off" aria-label="search">
          </td>
        </tr>
      </tbody>
    </table>
  </div>
</form>

Text Content

Business

search close

 * Solutions
   * By Challenge
       
     * By Challenge
         
       * By Challenge
         Learn more
         
     * Understand, Prioritize & Mitigate Risks
         
       * Understand, Prioritize & Mitigate Risks
         
         Improve your risk posture with attack surface management
         
         Learn more
         
     * Protect Cloud-Native Apps
         
       * Protect Cloud-Native Apps
         
         Security that enables business outcomes
         
         Learn more
         
     * Protect Your Hybrid World
         
       * Protect Your Hybrid, Multi-Cloud World
         
         Gain visibility and meet business needs with security
         
         Learn more
         
     * Securing Your Borderless Workforce
         
       * Securing Your Borderless Workforce
         
         Connect with confidence from anywhere, on any device
         
         Learn more
         
     * Eliminate Network Blind Spots
         
       * Eliminate Network Blind Spots
         
         Secure users and key operations throughout your environment
         
         Learn more
         
     * See More. Respond Faster.
         
       * See More. Respond Faster.
         
         Move faster than your adversaries with powerful purpose-built XDR,
         attack surface risk management, and zero trust capabilities
         
         Learn more
         
     * Extend Your Team
         
       * Extend Your Team. Respond to Threats Agilely
         
         Maximize effectiveness with proactive risk reduction and managed
         services
         
         Learn more
         
     * Operationalizing Zero Trust
         
       * Operationalizing Zero Trust
         
         Understand your attack surface, assess your risk in real time, and
         adjust policies across network, workloads, and devices from a single
         console
         
         Learn more
         
   * By Role
       
     * By Role
         
       * By Role
         Learn more
         
     * CISO
         
       * CISO
         
         Drive business value with measurable cybersecurity outcomes
         
         Learn more
         
     * SOC Manager
         
       * SOC Manager
         
         See more, act faster
         
         Learn more
         
     * Infrastructure Manager
         
       * Infrastructure Manager
         
         Evolve your security to mitigate threats quickly and effectively
         
         Learn more
         
     * Cloud Builder and Developer
         
       * Cloud Builder and Developer
         
         Ensure code runs only as intended
         
         Learn more
         
     * Cloud Security Ops
         
       * Cloud Security Ops
         
         Gain visibility and control with security designed for cloud
         environments
         
         Learn more
         
   * By Industry
       
     * By Industry
         
       * By Industry
         Learn more
         
     * Healthcare
         
       * Healthcare
         
         Protect patient data, devices, and networks while meeting regulations
         
         Learn more
         
     * Manufacturing
         
       * Manufacturing
         
         Protecting your factory environments – from traditional devices to
         state-of-the-art infrastructures
         
         Learn more
         
     * Oil & Gas
         
       * Oil & Gas
         
         ICS/OT Security for the oil and gas utility industry
         
         Learn more
         
     * Electric Utility
         
       * Electric Utility
         
         ICS/OT Security for the electric utility
         
         Learn more
         
     * Federal
         
       * Federal
         Learn more
         
     * Automotive
         
       * Automotive
         Learn more
         
     * 5G Networks
         
       * 5G Networks
         Learn more
         
   * Small & Midsized Business Security
       
     * Small & Midsized Business Security
       
       Stop threats with comprehensive, set-it-and-forget-it protection
       
       Learn more
       
 * Platform
   * Vision One Platform
       
     * Trend Vision One
       Our Unified Platform
       
       Bridge threat protection and cyber risk management
       
       Learn more
       
   * Attack Surface Management
       
     * Attack Surface Management
       
       Stop breaches before they happen
       
       Learn more
       
   * XDR (Extended Detection & Response)
       
     * XDR (Extended Detection & Response)
       
       Stop adversaries faster with a broader perspective and better context to
       hunt, detect, investigate, and respond to threats from a single platform
       
       Learn more
       
   * Cloud Security
       
     * Cloud Security
         
       * Trend Vision One™
         Cloud Security Overview
         
         The most trusted cloud security platform for developers, security
         teams, and businesses
         
         Learn more
         
     * Attack Surface Risk Management for Cloud
         
       * Attack Surface Risk Management for Cloud
         
         Cloud asset discovery, vulnerability prioritization, Cloud Security
         Posture Management, and Attack Surface Management all in one
         
         Learn more
         
     * XDR for Cloud
         
       * XDR for Cloud
         
         Extend visibility to the cloud and streamline SOC investigations
         
         Learn more
         
     * Workload Security
         
       * Workload Security
         
         Secure your data center, cloud, and containers without compromising
         performance by leveraging a cloud security platform with CNAPP
         capabilities
         
         Learn more
         
     * Container Security
         
       * Container Security
         
         Simplify security for your cloud-native applications with advanced
         container image scanning, policy-based admission control, and container
         runtime protection
         
         Learn more
         
     * File Storage Security
         
       * File Storage Security
         
         Security for cloud file/object storage services leveraging cloud-native
         application architectures
         
         Learn more
         
   * Endpoint Security
       
     * Endpoint Security
         
       * Endpoint Security Overview
         
         Defend the endpoint through every stage of an attack
         
         Learn more
         
     * XDR for Endpoint
         
       * XDR for Endpoint
         
         Stop adversaries faster with a broader perspective and better context
         to hunt, detect, investigate, and respond to threats from a single
         platform
         
         Learn more
         
     * Workload Security
         
       * Workload Security
         
         Optimized prevention, detection, and response for endpoints, servers,
         and cloud workloads
         
         Learn more
         
     * Industrial Endpoint Security
         
       * Industrial Endpoint Security
         Learn more
         
     * Mobile Security
         
       * Mobile Security
         
         On-premises and cloud protection against malware, malicious
         applications, and other mobile threats
         
         Learn more
         
   * Network Security
       
     * Network Security
         
       * Network Security Overview
         
         Expand the power of XDR with network detection and response
         
         Learn more
         
     * XDR for Network
         
       * XDR for Network
         
         Stop adversaries faster with a broader perspective and better context
         to hunt, detect, investigate, and respond to threats from a single
         platform
         
         Learn more
         
     * Network Intrusion Prevention (IPS)
         
       * Network Intrusion Prevention (IPS)
         
         Protect against known, unknown, and undisclosed vulnerabilities in your
         network
         
         Learn more
         
     * Breach Detection System (BDS)
         
       * Breach Detection System (BDS)
         
         Detect and respond to targeted attacks moving inbound, outbound, and
         laterally
         
         Learn more
         
     * Secure Service Edge (SSE)
         
       * Secure Service Edge (SSE)
         
         Redefine trust and secure digital transformation with continuous risk
         assessments
         
         Learn more
         
     * Industrial Network Security
         
       * Industrial Network Security
         Learn more
         
   * Email Security
       
     * Email Security
       
       Stop phishing, malware, ransomware, fraud, and targeted attacks from
       infiltrating your enterprise
       
       Learn more
       
   * OT Security
       
     * OT Security
         
       * OT Security
         
         Learn about solutions for ICS / OT security.
         
         Learn more
         
     * XDR for OT
         
       * XDR for OT
         
         Stop adversaries faster with a broader perspective and better context
         to hunt, detect, investigate, and respond to threats from a single
         platform
         
         Learn more
         
     * Industrial Network Security
         
       * Industrial Network Security
         Industrial Network Security
         
     * Industrial Endpoint Security
         
       * Industrial Endpoint Security
         Learn more
         
   * Threat Intelligence
       
     * Threat Intelligence
       
       Keep ahead of the latest threats and protect your critical data with
       ongoing threat prevention and analysis
       
       Learn more
       
   * All Products, Services and Trials
       
     * All Products, Services and Trials
       Learn more
       
 * Research
   * Research
       
     * Research
         
       * Research
         Learn more
         
     * Research, News, and Perspectives
         
       * Research, News, and Perspectives
         Learn more
         
     * Research and Analysis
         
       * Research and Analysis
         Learn more
         
     * Security News
         
       * Security News
         Learn more
         
     * Zero Day Initiatives (ZDI)
         
       * Zero Day Initiatives (ZDI)
         Learn more
         
 * Services
   * Our Services
       
     * Our Services
         
       * Our Services
         Learn more
         
     * Service Packages
         
       * Service Packages
         
         Augment security teams with 24/7/365 managed detection, response, and
         support
         
         Learn more
         
     * Managed XDR
         
       * Managed XDR
         
         Augment threat detection with expertly managed detection and response
         (MDR) for email, endpoints, servers, cloud workloads, and networks
         
         Learn more
         
     * Incident Response
         
       * Incident Response
           
         * Incident Response
           
           Our trusted experts are on call whether you're experiencing a breach
           or looking to proactively improve your IR plans
           
           Learn more
           
       * Insurance Carriers and Law Firms
           
         * Insurance Carriers and Law Firms
           
           Stop breaches with the best response and detection technology on the
           market and reduce clients’ downtime and claim costs
           
           Learn more
           
     * Support Services
         
       * Support Services
         Learn more
         
 * Partners
   * Partner Program
       
     * Partner Program
         
       * Partner Program Overview
         
         Grow your business and protect your customers with the best-in-class
         complete, multilayered security
         
         Learn more
         
     * Managed Security Service Provider
         
       * Managed Security Service Provider
         
         Deliver modern security operations services with our industry-leading
         XDR
         
         Learn more
         
     * Managed Service Provider
         
       * Managed Service Provider
         
         Partner with a leading expert in cybersecurity, leverage proven
         solutions designed for MSPs
         
         Learn more
         
     * Cloud Service Provider
         
       * Cloud Service Provider
         
         Add market-leading security to your cloud service offerings – no matter
         which platform you use
         
         Learn more
         
     * Professional Services
         
       * Professional Services
         
         Increase revenue with industry-leading security
         
         Learn more
         
     * Resellers
         
       * Resellers
         
         Discover the possibilities
         
         Learn more
         
     * Marketplace
         
       * Marketplace
         Learn more
         
     * System Integrators
         
       * System Integrators
         Learn more
         
   * Alliance Partners
       
     * Alliance Partners
         
       * Alliance Overview
         
         We work with the best to help you optimize performance and value
         
         Learn more
         
     * Technology Alliance Partners
         
       * Technology Alliance Partners
         Learn more
         
     * Our Alliance Partners
         
       * Our Alliance Partners
         Learn more
         
   * Partner Tools
       
     * Partner Tools
         
       * Partner Tools
         Learn more
         
     * Partner Login
         
       * Partner Login
         Login
         
     * Education and Certification
         
       * Education and Certification
         Learn more
         
     * Partner Successes
         
       * Partner Successes
         Learn more
         
     * Distributors
         
       * Distributors
         Learn more
         
     * Find a Partner
         
       * Find a Partner
         Learn more
         
 * Company
   * Why Trend Micro
       
     * Why Trend Micro
         
       * Why Trend Micro
         Learn more
         
     * Customer Success Stories
         
       * Customer Success Stories
         Learn more
         
     * The Human Connection
         
       * The Human Connection
         Learn more
         
     * Industry Accolades
         
       * Industry Accolades
         Learn more
         
     * Strategic Alliances
         
       * Strategic Alliances
         Learn more
         
   * About Us
       
     * About Us
         
       * About Us
         Learn more
         
     * Trust Center
         
       * Trust Center
         Learn more
         
     * History
         
       * History
         Learn more
         
     * Diversity, Equity and Inclusion
         
       * Diversity, Equity and Inclusion
         Learn more
         
     * Corporate Social Responsibility
         
       * Corporate Social Responsibility
         Learn more
         
     * Leadership
         
       * Leadership
         Learn more
         
     * Security Experts
         
       * Security Experts
         Learn more
         
     * Internet Safety and Cybersecurity Education
         
       * Internet Safety and Cybersecurity Education
         Learn more
         
     * Legal
         
       * Legal
         Learn more
         
     * Investors
         
       * Investors
         Learn more
         
   * Connect with Us
       
     * Connect with Us
         
       * Connect with Us
         Learn more
         
     * Newsroom
         
       * Newsroom
         Learn more
         
     * Events
         
       * Events
         Learn more
         
     * Careers
         
       * Careers
         Learn more
         
     * Webinars
         
       * Webinars
         Learn more
         

Back

Back

Back

Back

 * Free Trials
 * Contact Us

Looking for home solutions?
Under Attack?
4 Alerts

Back
Unread
All


 * Join us at AWS re:Invent Nov. 27-Dec. 1
   
   close
   
   Engage with us >

 * Understanding ChatGPT's potential for misuse via malware creation
   
   close
   
   Learn more >

 * How threat actors leverage file-sharing to harvest credentials
   
   close
   
   Learn more >

 * Understanding how stolen data is acquired and sold
   
   close
   
   Protect your organization >

Folio (0)
Support
 * Business Support Portal
 * Business Community
 * Virus and Threat Help
 * Education and Certification
 * Contact Support
 * Find a Support Partner

Resources
 * Cyber Risk Index/Assessment
 * CISO Resource Center
 * DevOps Resource Center
 * What Is?
 * Threat Encyclopedia
 * Cloud Health Assessment
 * Cyber Insurance
 * Glossary of Terms
 * Webinars

Log In
 * Support
 * Partner Portal
 * Cloud One
 * Product Activation and Management
 * Referral Affililate

Back

arrow_back
search



close

Content has been added to your Folio

Go to Folio (0) close

Cyber Threats


PARASITESNATCHER: HOW MALICIOUS CHROME EXTENSIONS TARGET BRAZIL

We detail the modular framework of malicious Chrome extensions that consist of
various highly obfuscated components that leverage Google Chrome API to monitor,
intercept, and exfiltrate victim data.

By: Aliakbar Zahravi, Peter Girnus November 23, 2023 Read time: 12 min (3275
words)

Save to Folio

Subscribe

--------------------------------------------------------------------------------

Our investigations on potential security threats uncovered a malicious Google
Chrome extension that we named “ParaSiteSnatcher.” The ParaSiteSnatcher
framework allows threat actors to monitor, manipulate, and exfiltrate highly
sensitive information from multiple sources. ParaSiteSnatcher also utilizes the
powerful Chrome Browser API to intercept and exfiltrate all POST requests
containing sensitive account and financial information before the HTTP request
initiates a transmission control protocol (TCP) connection.

Our research shows that the malicious extension is specifically designed to
target users in Latin America, particularly Brazil; it exfiltrates data from
Banco do Brasil- and Caixa Econômica Federal (Caixa)-related URLs. It can also
initiate and manipulate transactions in PIX, a Brazilian instant payment
ecosystem, and payments made through Boleto Bancario, another payment method
regulated by the Bank of Brazil. We also observed that it can exfiltrate
Brazilian Tax ID numbers for both individuals and businesses, as well as
cookies, including those used for Microsoft accounts.  

Once installed, the extension manifests with the help of extensive permissions
enabled through the Chrome extension, allowing it to manipulate web sessions,
web requests, and track user interactions across multiple tabs using the Chrome
tabs API. The malware includes various components that facilitate its operation,
content scripts that enable malicious code injection into web pages, monitor
Chrome tabs, and intercept user input and web browser communication.

It is worth noting that while ParaSiteSnatcher specifically targets Google
Chrome browsers, the malicious extension will also work on browsers that support
Chrome extension API and runtime, such as Chromium-based browsers like newer
versions of Microsoft Edge, Brave, and Opera. These extensions could potentially
be compatible with Firefox and Safari as well, but changes such as the browser
namespace are necessary.

The ParaSiteSnatcher downloader

ParaSiteSnatcher is downloaded through a VBScript downloader hosted on Dropbox
and Google Cloud and installed onto an infected system. 

Our analysis has identified three distinct variants of the VBScript downloader,
which are characterized by differing levels of obfuscation and complexity:

 *  
 * Variant 1. This variant presents a straightforward approach where the payload
   is not obfuscated, making it relatively easier to analyze and understand.
 *  
 * Variant 2. In this iteration, critical strings within the payload are
   obfuscated using a Reverse String technique. This adds a layer of complexity
   to the code, requiring a reverse operation to decipher the original content.
 *  
 * Variant 3. This variant incorporates additional obfuscation techniques. It
   includes junk code that serves to confuse the analysis process, anti-debug
   and anti-tamper protections, alongside the use of randomly generated names
   for variables and functions to prevent easy pattern detection. It also
   utilizes Reverse String obfuscation to further conceal the payload,
   presenting a more challenging structure for analysts to decipher.

Upon execution, the downloader performs an initial check for the presence of the
%ProgramFiles%\Google\Chrome\Application\chrome.exe file, and the
%APPDATA%\%USERNAME% folder. If found not present, the script will terminate its
process.

Figure 1. Verifying chrome installation and AppData path presence

The malware establishes communication with the attacker’s C&C by constructing
and sending a GET request to hxxps[:]//storage.googleapis[.]com/98jk3m5azb/-.
The response from the server is an obfuscated list of URLs. 

The malware then de-obfuscates this list with a series of string manipulations
performed on the C&C response that reverses the string back to its original
order. It then replaces specific characters with their correct counterparts to
reconstruct the URLs:

 *  
 * "[h]" is replaced with "https://", specifying the protocol part of the URL.
 *  
 * "-" is replaced with ".", reconstructing the domain names.
   
 *  
 * "_" is substituted with "/", fixing the path structure.
 *  
 * ">" is replaced with ":", correcting port specifications.

Figure 2. De-obfuscating URLs from the C&C response

Once the actual URLs are retrieved, they are used to download additional
malicious modules masquerading as Google Chrome extensions.

Figure 3. The list of obfuscated URLs from the threat actor’s C&C response

The first URL from above list (hxxps[:]//rezumdolly[.]com:8443/api/alert) is
used to register an infected system and notify the attacker. The malware first
utilizes the Windows Management Instrumentation (WMI) service to perform a query
against the Win32_OperatingSystem class, which retrieves details about the
operating system that are subsequently sent to the attacker’s C&C server.

Figure 4. ParaSiteSnatcher gathers the victim’s system information upon arrival

It then constructs a .json-formatted string that encapsulates several pieces of
system information as follows:

 * comp. The computer's name, which can be used to uniquely identify the system
   on a network.
 *  
 * user. The registered user's name, providing insights into who uses or owns
   the system.
 *  
 * version. The operating system version, indicating the specific build and
   potential vulnerabilities.
 *  
 * arch. The architecture of the operating system (e.g., 32-bit or 64-bit),
   which is useful for tailoring further attacks to the system's specifications.
 *  
 * caption. A descriptive label for the operating system, often including the
   edition (e.g., Windows 10 Pro).

Figure 5. Registering an infected system with the attacker's command and control
server

The malware uses the down() function to download and save ParaSiteSnatcher
malicious extension modules on an infected system’s %APPDATA%\%USERNAME%
directory.

Figure 6. The ParaSiteSnatcher download function

The malware then attempts to locate and delete Chrome shortcuts by searching for
any shortcuts that contain "chrome.lnk" in the Desktop, Public Desktop, and
Quick Launch folders.

Figure 7. ParaSiteSnatcher removing Chrome shortcuts from the victim’s Desktop
and Quick Launch folders with VBScript

To achieve persistence on the victim’s system and load malicious execution on
every execution, the malware creates a Google Chrome shortcut on the desktop,
which is configured to launch the browser with custom startup parameters. These
parameters include the specification of a default user profile directory and the
initiation of a malicious browser extension housed within the user's application
data folder. This process is engineered to ensure that the malicious extension
is loaded each time Chrome is started via the created shortcut.

Figure 8. The malware’s persistence

Extension and C&C communication

Figure 9. A diagram showing how the different components of the ParaSiteSnatcher
Chrome extension communicate.

The communication mechanism employed by ParaSiteSnatcher Chrome extensions rely
heavily on using the Chrome sendMessage API to communicate with various
extension components when specific conditions are met. 

When messages are received, the malicious Chrome extension executes internal
functions on these events: some components pass along the targeted and processed
and targeted data directly to the attacker C&C, while most of the other
components contain logic that can receive and update commands directly from the
threat actor. 

The extension’s service worker, which we will discuss further into this blog,
leverages the chrome.windows and chrome.tabs API for navigating and focusing the
document object model (DOM) that other ParaSiteSnatcher components rely on. 

Analyzing ParaSiteSnatcher Chrome extension files

In this section we explore the various files that comprise the ParaSiteSnatcher
Framework's malicious Chrome extension. 


Figure 10. Properties of the malicious Chrome extension we investigated

manifest.json

Every Google Chrome extension includes a manifest.json file in its root
directory. This background manifest key contains essential information, such as
the extension’s name, version, permissions, and any scripts associated with the
Chrome extension. The extension uses a service worker (yyva.js) as part of its
background processes for handling tasks, orchestrating modules and data
synchronization in the background.

Figure 11. The manifest.json file in the ParaSiteSnatcher’s root directory

The manifest.json file contains the following:

 * Basic metadata. This includes the name, description, version, and author key
   of the browser extension. 
 * Service workers. These are JavaScript files that act as the extension's
   primary event handler. These events include more than just servicing web
   requests and can respond to events like navigating a new page, clicking
   notifications, and opening or closing tabs. Not that Chrome makes the
   critical distinction between a web service worker and an extension service
   worker to highlight that the extension service worker is more than just a web
   request proxy service. The service worker specified in the background key is
   the extension service worker.
 * Content scripts. These allow developers to statistically load JavaScript
   files when webpages are opened that match a specific URL pattern.
 *  Permissions. These determine which capabilities are exposed to their
   respective extension. 

In the sample of the ParaSiteSnatcher extension we investigated, we saw some
critical content_script keys that determine what scripts are injected, where
they are injected, and how they behave:

 * matches. This type of key specifies the pattern to be used for matching.
   The <all_urls> value matches any URL that starts with a permitted scheme,
   such as http, https, and file.
 * run_at. This key specifies when the script should be injected into the page,
   where the document_end value injects the script while the page resources are
   still loading.
 * all_frames. This is a Boolean value.  When set to true, the extension will
   inject scripts into all <iframe> elements even if the frame is not the
   topmost in the tab.
 * persistent. When the persistent Boolean value is true, the extension
   developer can access the chrome.webRequest API to block or modify network
   requests. This is the only use case for setting the persistent boolean to
   true; by default, this value is set to false for performance reasons. 

Additionally, the malicious extension contained host_permissions among the
permissions in its manifest file. The host_permission key grants extra
permissions for the extension’s API to read and modify host data such as
accessing the API cookies, receiving events using the webRequest API,
programmatically injecting scripts, bypassing tracking protections, and reading
tab-specific metadata. It can also access XMLHttpRequest and fetch access to
origins without cross-origin restrictions. 


If an extension uses the host_permissions key, the user could be prompted to
grant these permissions to the extension. As of June 2023, Safari, Firefox, and
some Chromium-based browsers don't prompt the user during installation. In this
malicious sample, the host_permissions allow the extension to read and modify
all URLs using the <all_urls> value.

ParaSiteSnatcher also contains the permissions JSON key, which contains specific
WebExtension API keywords that the extension requests to use. The malicious
extension requests the following WebExtension JavaScript APIs:

 * webNavigation. This API adds an event listener for various stages of
   navigation, such as in response to a user action, like clicking a link or
   adding a URL in the location bar.
 *  notifications. This API allows extensions to create and display
   notifications to users in the system tray.
 * declarativeNetRequest. This API allows extensions to specify conditions and
   actions on handling network requests, allowing extensions to block and
   upgrade network requests without explicit host permissions.
 * declarativeNetRequestFeedback. This API allows extensions to access functions
   and events that return information on declarative rules, such as those
   through the declarativeNetrequest API.
 * scripting. The scripting API allows the insertion of JavaScript into
   websites, such as through the scripting.executeScript() and
   scripting.registerContentScripts() methods.
 * webRequest. The webRequest API grants access to add event listeners to HTTP
   and WebSocket requests. These event listeners can receive detailed
   information about such requests, including the ability to modify and cancel
   these requests.
 *  storage. The storage API allows extensions to store and receive data and
   listen for changes in stored data.
 * tabs. The tabs API allows extensions to interact with the Chrome browser’s
   tab system, including creating, modifying, and rearranging browser tabs. This
   powerful API also includes taking screenshots and communicating with a tab’s
   content scripts.
 * activeTab. This API permits access to the currently active tab when users
   execute browser and page actions.
 * cookies. The cookies API allows the extension to query and modify cookies and
   be notified of cooking changes.

It is important to note that many other API permissions exist in Chrome for
developers API Reference. From a security perspective, it is essential to
understand that web browser extensions can declare many permissions, and not all
extensions will request the user to grant explicit access. This highlights the
essential need to understand what any downloaded extension does and its declared
permission levels. 


yyva.js

This component is an Extension Service Worker or Service Worker, the central
event handler for Google Chrome extensions that handles web events and messages
from other extension components. The extension service worker can respond
to standard service worker events in addition to extension events, such as
navigating to a new page, clicking a notification, or closing a tab. This
service worker is declared with the service_worker key.

In our research, all extension components are highly obfuscated, but after
deobfuscating each component and cleaning up the code, we uncovered the
following important extension service worker features working with the Chrome
API:

 * Event listening and handling. The yavvy.js service worker is tasked with
   listening for events using the chrome.runtime.onMessage.addListener API.
   Within Chrome extensions, various components can leverage the Chrome API to
   message each other using the sendMessage API. The service worker is
   specifically tasked with listening for navigation, focus, and getcookies
   messages.
 *  
 * Listening and intercepting POST requests. The yavvy.js service worker uses
   the Chrome.webRequest.onBeforeRequest.addListener to create a callback
   function to listen for web request events containing a POST request, as well
   as gather tab information using the chrome.tabs.get API, which it uses for
   analysis.

Figure 12. ParaSiteSnatcher uses chrome.runtime.onMessage.addListener to listen
for specific events.

Despite its extensive listening, it is worth noting that ParaSiteSnatcher
excludes local network addresses and C&C domain from its monitoring.

Figure 13. ParaSiteSnatcher excludes local network addresses and C&C domain from
its monitoring.

It also intercepts and monitors user activity, and handles the following
messages received from other modules:

 * messageDetails.type == 'focus'
 *  
 * messageDetails.type == 'navigate'
 *  
 * messageDetails.type == 'getcookie'

The functions that handle the navigate and focus events use the chrome.windows
and chrome.tabs API for navigating and focusing the document object model (DOM).
Other components of this malicious Chrome extension leverage these messages
extensively.

jsync.js (Jquery 3.3.1) 

This file is injected as a Chrome extension dependency and is a content script
used primarily for Asynchronous JavaScript and XML (AJAX) communication with the
attacker C&C to exfiltrate sensitive data from infected users.

sovvy.js 

This primary content script in the malicious Chrome extension periodically
monitors specific forms and elements on a webpage and sets up event listeners on
certain buttons every two seconds. It leverages the Chrome runtime API using the
chrome.runtime.onMessage.addListener API method to listen for the custom
messages passed between various extension events with the types, “lixo,”
“cookie,” and “timer.” When events with these message types are initiated, they
in turn trigger ParaSiteSnatcher to run these specific functions: 

 * Intercepting POST requests. The lixo message is a catch-all event and does
   not look for specific URL patterns. Instead, it tracks all POST requests in
   which the attackers search for sensitive information such as usernames,
   passwords, emails, and credit card information. 

Figure 14. ParaSiteSnatcher tracks all POST requests
 * Stealing cookies and user sessions. The cookie message sends a POST request
   to the attacker C&C for cookie and session theft.


Figure 15. ParaSiteSnatcher also gathers data related to cookies.
 * Stealing Microsoft cookies. When cookies matching Microsoft live.com exist,
   the sovvy.js file sends a message using the chrome.runtime.sendMessage API to
   send this data to the service worker, which processes this data to filter and
   extract the found Microsoft account cookies. These can be leveraged for
   account theft and pass-the-cookie attacks as well as pivoting to the cloud.

Figure 16. ParaSiteSnatcher uses the chrome.runtime.sendMessage API to get a
victim’s user information related to Microsoft accounts.
 * Stealing Banking Details. Our investigation of ParaSiteSnatcher revealed that
   the malicious extension conducts multiple URL checks related to Brazilian
   online banking companies, including Banco do Brasil and Caixa Econômica
   Federal. When the victim interacts with URLs related to these financial
   institutions, the malicious Chrome extension begins processing the data,
   looking for items such as usernames, passwords, and credit cards numbers, and
   sending the data with a POST request to the attacker’s C&C.

Figure 17. ParaSiteSnatcher looks out for communication with banking sites and
get password entries by victims
 * Fetching commands from the attacker’s C&C. Within this the sovvy.js script is
   the ability for the malicious Chrome extension to retrieve commands from the
   attacker C&C server with a standard HTTP GET request.

Figure 18. sovvy.js contains script that retrieves commands from the threat
actor’s C&C server.

33nhauh.js 

The 33nhuah.js file contains business logic to monitor bank account details and
perform PIX instant payment actions. PIX is an instant payment platform created
and regulated by the Banco Central do Brasil (Central Bank of Brazil). 

Some key features of this content script include HTML templates for password
input forms, definitions for enum type data representing command types, account
information, PIX key types, and parameters for PIX transactions. This content
script also contains functions to monitor bank account balances and perform PIX
transactions. Additionally, there are functions that manipulate the user
interface, such as setting and resetting forms, clicking on menu items, and
hiding or loading process indicators. 

This content script uses the standard HTML DOM selector to find specific
elements containing sensitive PIX elements such as receiving PIX institution
names, and user account information such as:

 * CPF/CNPJ (Brazilian Individual & Business Taxpayer Registration) details
 *  
 * Email addresses
 *  
 * Cellphone numbers
 *  
 * PIX Keys


Figure 19. ParaSiteSnatcher monitors activity related to PIX transactions,
gathers victim data from these transactions, and performs actions such as
navigating the PIX menu and selecting buttons within its interface.

unpgp2.js 

The content script unpgp2.js is designed to navigate, focus, and interact with
the internet banking interface of the Caixa Econômica Federal’s web interface.
This content script performs various actions such as navigating pages, fetching
account details, focusing on elements, executing financial transactions and
initiating PIX transactions.

Figure 20. ParSiteSnatcher specifically looks for activity with URLs related to
Caixa Econômica Federal.

s12ih0a.js

This content script primarily contains logic that is used to periodically
monitor windows and tabs content specifically those that contain or are related
to the following:

 * Boleto Bancário 
 *  
 * The CPF (Cadastro de Pessoas Físicas or Natural Persons Register) numbers of
   both the payer and receiver in transactions
 *  
 * The CNPJ (Cadastro Nacional da Pessoa Juridica or Taxpayer Identification)
   number of both the payer and receiver in transactions 
 *  
 * Bank payment slips

The logic contained in this content script is called during specific intervals
to monitor the DOM and user-input through the sovvy.js content script. The
s12ih0a.js content script will also POST elements such as telephone numbers and
email addresses to the attacker C&C.

Figure 21. The ParaSiteSnatcher data exfiltration to its C&C server

In the following table, we summarize the functions of each ParaSiteSnatcher
extension component:

Module Name Functions yyva.js 

async function timerMonitor()

function getCookies()

async function navigate()

async function setFocusTab()

function addLog()

async function analyzeRequest()

sovvy.js 

function setCommandRetorno()

function updateCmd()

function timerMonitor()

function postSession()

function postLixo()

function getCmd()

function updateCmd()

function updateStatusOn()

function getVersion()

function getUser()

function getElement()

function addlog()

function trim()

function toLowerCase()

function extractDigits()

function getForm()

function preparePostData()

function buildInputMap()

function checkElementClick()

function checkInputPost()

function ValidateEmail()

function GenerateToken()

function SetToken()

function updateUserId()

33nhauh.js 

function monitorBB()

function resetCommand_BB()

function getSaldo_BB()

function clickMenuSaldo()

function focoTab_BB()

function hideProcesso()

function action_pix_BB()

function checkComprovante()

function setSConta()

function setValor()

function setChave()

function clickMenuPix()

function clickMenu()

function setAccountPasswordForm()

function getAgencyAndAccountNumber()

function resetAccountPasswordForm()

s12ih0a.js 

function monitor2Via()

function setEventDesco()

function setEventBB()

function click_isPagina()

function setMessageDesco()

function setMessageBB()

function setHtmlBB()

function setHtmlDesco()

function getDadosSegundaVia()

function post2Via()

function checkDebugging()

function innerFunction()

unpgp2.js 

function monitorAzul()

function get_azul_ass()

function get_azul_Saldo()

function focoTab_Azul()

function resetCommand_Azul()

function get_azul_agcc()

function azul_pedidos_automaticos()

Conclusion 

The use of malicious Google Chrome extensions by leveraging the powerful Chrome
API in ways specifically designed to intercept, exfiltrate, and potentially
modify sensitive user data underscores the importance of being vigilant when
granting permissions to extensions and when using web browsers.
ParaSiteSnatcher’s multifaceted approach to obfuscate its arrival onto victim’s
systems also ensures persistence and stealth, making detection and removal
efforts challenging, so users should be doubly watchful of the specific
extensions they download and install onto their browsers. 

Despite our investigations showing that ParaSiteSnatcher specifically targets
Google Chrome browsers, users who utilize other browsers that are Chromium-based
and that support various APIs used by Chrome extensions should be equally wary.

Indicators of Compromise (IoCs)

You can find the full list of ParaSiteSnatcher IoCs here.

Tags
Articles, News, Reports | Cyber Threats | Research


AUTHORS

 * Aliakbar Zahravi
   
   Staff Researcher

 * Peter Girnus
   
   Sr. Threat Researcher

Contact Us
Subscribe


RELATED ARTICLES

 * Exploring Weaknesses in Private 5G Networks
 * Attack Signals Possible Return of Genesis Market, Abuses Node.js, and EV Code
   Signing
 * Beware: Lumma Stealer Distributed via Discord CDN

See all articles


Try our services free for 30 days

 * Start your free trial today

 * 
 * 
 * 
 * 
 * 


RESOURCES

 * Blog
 * Newsroom
 * Threat Reports
 * DevOps Resource Center
 * CISO Resource Center
 * Find a Partner


SUPPORT

 * Business Support Portal
 * Contact Us
 * Downloads
 * Free Trials
 * 
 * 


ABOUT TREND

 * About Us
 * Careers
 * Locations
 * Upcoming Events
 * Trust Center
 * 

Select a country / region

United States expand_more
close

THE AMERICAS

 * United States
 * Brasil
 * Canada
 * México

MIDDLE EAST & AFRICA

 * South Africa
 * Middle East and North Africa

EUROPE

 * België (Belgium)
 * Česká Republika
 * Danmark
 * Deutschland, Österreich Schweiz
 * España
 * France
 * Ireland
 * Italia
 * Nederland
 * Norge (Norway)
 * Polska (Poland)
 * Suomi (Finland)
 * Sverige (Sweden)
 * Türkiye (Turkey)
 * United Kingdom

ASIA & PACIFIC

 * Australia
 * Центральная Азия (Central Asia)
 * Hong Kong (English)
 * 香港 (中文) (Hong Kong)
 * भारत गणराज्य (India)
 * Indonesia
 * 日本 (Japan)
 * 대한민국 (South Korea)
 * Malaysia
 * Монголия (Mongolia) and рузия (Georgia)
 * New Zealand
 * Philippines
 * Singapore
 * 台灣 (Taiwan)
 * ประเทศไทย (Thailand)
 * Việt Nam

Privacy | Legal | Accessibility | Site map

Copyright ©2023 Trend Micro Incorporated. All rights reserved


sXpIBdPeKzI9PC2p0SWMpUSM2NSxWzPyXTMLlbXmYa0R20xk

This website uses cookies for website functionality, traffic analytics,
personalization, social media functionality and advertising. Our Cookie Notice
provides more information and explains how to amend your cookie settings.Learn
more

Cookies Settings Accept

word word word word word word word word word word word word word word word word
word word word word word word word word word word word word word word word word
word word word word word word word word word word word word word word word word
word word word word word word word word word word word word word word word word
word word word word word word word word word word word word word word word word
word word word word word word word word word word word word word word word word
word word word word word word word word word word word word word word word word
word word word word word word word word word word word word word word word word
word word word word word word word word word word word word word word word word
word word word word word word word word word word word word word word word word
word word word word word word word word word word word word word word word word
word word word word word word word word word word word word word word word word
word word word word word word word word

mmMwWLliI0fiflO&1
mmMwWLliI0fiflO&1
mmMwWLliI0fiflO&1
mmMwWLliI0fiflO&1
mmMwWLliI0fiflO&1
mmMwWLliI0fiflO&1
mmMwWLliI0fiflO&1



Sumo