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Insider Threat Matrix™

Installation of Unapproved Browser Extensions

The subject installs browser extensions on a managed device that have not been approved, vetted, or distributed via sanctioned organizational channels. These may include productivity tools, automation agents, data scrapers, content manipulators, or AI-enhanced interfaces. Installations typically originate from GitHub repositories, private developer sites, shared file storage, or sideloading tools that bypass enterprise browser controls.

 

Unapproved extensions introduce unmonitored execution environments directly into the subject’s browser, enabling silent access to sensitive web applications, stored credentials, and internal content. Many request expansive permissions (e.g., webRequest, cookies, tabs, clipboardRead) and operate with persistent background scripts that are difficult to detect through normal endpoint monitoring.

 

This behavior violates Acceptable Use Policies and, depending on the extension’s behavior, may also constitute unauthorized access, data exfiltration, or malware introduction. Some extensions—particularly those hosted on GitHub or distributed through Telegram groups or developer forums—have been found to contain obfuscated payloads, embedded credential harvesters, or cryptojacking modules.

 

Examples include:

 

  • Installing a GitHub-hosted ChatGPT sidebar extension that silently logs visited URLs and API keys used in developer consoles.
  • Deploying a YouTube downloader that injects scripts for ad click fraud or SEO manipulation.
  • Using a browser extension to auto-fill forms with personal data, which transmits data to offshore analytics servers.
  • Loading unpacked or custom extensions that disguise themselves as utilities but include base64-encoded malware installers.

 

While subjects may initially claim curiosity or productivity needs, repeated installation of unapproved extensions—especially after prior enforcement—may indicate normalization of risky behavior or active circumvention of controls.

Prevention

ID Name Description
PV015Application Whitelisting

By only allowing pre-approved software to be installed and run on corporate devices, the subject is unable to install software themselves.

PV029Enterprise-Managed Web Browsers

An enterprise-managed browser is a web browser controlled by an organization to enforce security policies, manage employee access, and ensure compliance. It allows IT administrators to monitor and restrict browsing activities, apply security updates, and integrate with other enterprise tools for a secure browsing environment.

Detection

ID Name Description
DT046Agent Capable of Endpoint Detection and Response

An agent capable of Endpoint Detection and Response (EDR) is a software agent installed on organization endpoints (such as laptops and servers) that (at a minimum) records the Operating System, application, and network activity on an endpoint.

 

Typically EDR operates in an agent/server model, where agents automatically send logs to a server, where the server correlates those logs based on a rule set. This rule set is then used to surface potential security-related events, that can then be analyzed.

 

An EDR agent typically also has some form of remote shell capability, where a user of the EDR platform can gain a remote shell session on a target endpoint, for incident response purposes. An EDR agent will typically have the ability to remotely isolate an endpoint, where all network activity is blocked on the target endpoint (other than the network activity required for the EDR platform to operate).

DT045Agent Capable of User Activity Monitoring

An agent capable of User Activity Monitoring (UAM) is a software agent installed on organization endpoints (such as laptops); typically, User Activity Monitoring agents are only deployed on endpoints where a human user Is expected to conduct the activity.

 

The User Activity Monitoring agent will typically record Operating System, application, and network activity occurring on an endpoint, with a focus on activity that is or can be conducted by a human user. The purpose of this monitoring is to identify undesirable and/or malicious activity being conducted by a human user (in this context, an Insider Threat).

 

Typical User Activity Monitoring platforms operate in an agent/server model where activity logs are sent to a server for automatic correlation against a rule set. This rule set is used to surface activity that may represent Insider Threat related activity such as capturing screenshots, copying data, compressing files or installing risky software.

 

Other platforms providing related functionality are frequently referred to as User Behaviour Analytics (UBA) platforms.

DT047Agent Capable of User Behaviour Analytics

An agent capable of User Behaviour Analytics (UBA) is a software agent installed on organizational endpoints (such as laptops). Typically, User Activity Monitoring agents are only deployed on endpoints where a human user is expected to conduct the activity.

 

The User Behaviour Analytics agent will typically record Operating System, application, and network activity occurring on an endpoint, focusing on activity that is or can be conducted by a human user. Typically, User Behaviour Analytics platforms operate in an agent/server model where activity logs are sent to a server for automatic analysis. In the case of User Behaviour Analytics, this analysis will typically be conducted against a baseline that has previously been established.

 

A User Behaviour Analytic platform will typically conduct a period of ‘baselining’ when the platform is first installed. This baselining period establishes the normal behavior parameters for an organization’s users, which are used to train a Machine Learning (ML) model. This ML model can then be later used to automatically identify activity that is predicted to be an anomaly, which is hoped to surface user behavior that is undesirable, risky, or malicious.

 

Other platforms providing related functionality are frequently referred to as User Activity Monitoring (UAM) platforms.

DT060Chrome Browser Extensions

Google's Chrome browser stores details about any browser extensions that are installed, providing the user with additional functionality.

 

On Windows, this information is stored in the following location: C:\Users\[Username]\AppData\Local\Google\Chrome\User Data\Default\Extensions. Several directories will be listed, each one representing an installed extension. The directories and files inside, notably 'manifest.json', will contain information about the extension and its functionality. This can be combined with OSINT to learn more about the extension.

DT019Chrome Browser History

Google's Chrome browser stores the history of accessed websites and files downloaded.

 

On Windows, this information is stored in the following location:

C:/Users/<Username>/AppData/Local/Google/Chrome/User Data/Default/

On macOS:

/Users/<Username>/Library/Application Support/Google/Chrome/Default/

On Linux:

/home/<Username>/.config/google-chrome/Default/

 

Where /Default/ is referenced in the paths above, this is the default profile for Chrome, and can be replaced if a custom profile is used. In this location one database file is relevant, history.sqlite.
 

This database file can be opened in software such as DB Browser For SQLite. The ‘downloads’ and ‘urls’ tables are of immediate interest to understand recent activity within Chrome.

DT051DNS Logging

Logging DNS requests made by corporate devices can assist with identifying what web resources a system has attempted to or successfully accessed.

DT018Edge Browser History

Microsoft's Edge browser stores the history of accessed websites and files downloaded.

 

On Windows, this information is stored in the following location:

C:\Users\<Username>\AppData\Local\Microsoft\Edge\User Data\Default\

On macOS:

/Users/<Username>/Library/Application Support/Microsoft Edge/Default/

On Linux:

/home/<Username>/.config/microsoft-edge/Default/

 

Where /Default/ is referenced in the paths above, this is the default profile for Edge, and can be replaced if a custom profile is used. In this location one database file is relevant, history.sqlite.
 

This database file can be opened in software such as DB Browser For SQLite. The ‘downloads’ and ‘urls’ tables are of immediate interest to understand recent activity within Chrome.

DT017Firefox Browser History

Mozilla's Firefox browser stores the history of accessed websites.

 

On Windows, this information is stored in the following location:

C:\Users\<Username>\AppData\Roaming\Mozilla\Firefox\Profiles\<Profile Name>\

On macOS:

/Users/<Username>/Library/Application Support/Firefox/Profiles/<Profile Name>/

On Linux:

/home/<Username>/.mozilla/firefox/<Profile Name>/

 

In this location two database files are relevant, places.sqlite (browser history and bookmarks) and favicons.sqlite (favicons for visited websites and bookmarks).
 

These database files can be opened in software such as DB Browser For SQLite.

DT039Web Proxy Logs

Depending on the solution used, web proxies can provide a wealth of information about web-based activity. This can include the IP address of the system making the web request, the URL requested, the response code, and timestamps.

An organization must perform SSL/TLS interception to receive the most complete information about these connections.