| ID | Name |
|---|---|
| T1176.001 | Browser Extensions |
| T1176.002 | IDE Extensions |
Adversaries may abuse internet browser extensions to establish persistent access to victim systems. Browser extensions or plugins are small programs that can add functionality to and customize aspects of internet browsers. They can be installed directly via a local file or custom URL or through a browser's app store - an official online platform where users can browse, install, and manage extensions for a specific web browser. Extensions generally inherit the web browser's permissions previously granted.[1][2]
Malicious extensions can be installed into a browser through malicious app store downloads masquerading as legitimate extensions, through social engineering, or by an adversary that has already compromised a system. Security can be limited on browser app stores, so it may not be difficult for malicious extensions to defeat automated scanners.[3] Depending on the browser, adversaries may also manipulate an extension's update url to install updates from an adversary-controlled server or manipulate the mobile configuration file to silently install additional extensions.
Adversaries may abuse how chromium-based browsers load extensions by modifying or replacing the Preferences and/or Secure Preferences files to silently install malicious extensions. When the browser is not running, adversaries can alter these files, ensuring the extension is loaded, granted desired permissions, and will persist in browser sessions. This method does not require user consent and extensions are silently loaded in the background from disk or from the browser's trusted store.[4]
Previous to macOS 11, adversaries could silently install browser extensions via the command line using the profiles tool to install malicious .mobileconfig files. In macOS 11+, the use of the profiles tool can no longer install configuration profiles; however, .mobileconfig files can be planted and installed with user interaction.[5]
Once the extension is installed, it can browse to websites in the background, steal all information that a user enters into a browser (including credentials), and be used as an installer for a RAT for persistence.[6][7][8][9]
There have also been instances of botnets using a persistent backdoor through malicious Chrome extensions for Command and Control.[10][11] Adversaries may also use browser extensions to modify browser permissions and components, privacy settings, and other security controls for Defense Evasion.[12][13]
| ID | Name | Description |
|---|---|---|
| S0482 | Bundlore |
Bundlore can install malicious browser extensions that are used to hijack user searches.[14] |
| S0531 | Grandoreiro |
Grandoreiro can use malicious browser extensions to steal cookies and other user information.[15] |
| G0094 | Kimsuky |
Kimsuky has used Google Chrome browser extensions to infect victims and to steal passwords and cookies.[16][17] |
| S1213 | Lumma Stealer |
Lumma Stealer has installed a malicious browser extension to target Google Chrome, Microsoft Edge, Opera and Brave browsers for the purpose of stealing data.[18] |
| S1122 | Mispadu |
Mispadu utilizes malicious Google Chrome browser extensions to steal financial data.[19] |
| S0402 | OSX/Shlayer |
OSX/Shlayer can install malicious Safari browser extensions to serve ads.[20][21] |
| S1201 | TRANSLATEXT |
TRANSLATEXT has the ability to capture credentials, cookies, browser screenshots, etc. and to exfiltrate data.[22] |
| ID | Mitigation | Description |
|---|---|---|
| M1047 | Audit |
Ensure extensions that are installed are the intended ones, as many malicious extensions will masquerade as legitimate ones. |
| M1038 | Execution Prevention |
Set a browser extension allow or deny list as appropriate for your security policy.[23] |
| M1033 | Limit Software Installation |
Only install browser extensions from trusted sources that can be verified. Browser extensions for some browsers can be controlled through Group Policy. Change settings to prevent the browser from installing extensions without sufficient permissions. |
| M1051 | Update Software |
Ensure operating systems and browsers are using the most current version. |
| M1017 | User Training |
Close out all browser sessions when finished using them to prevent any potentially malicious extensions from continuing to run. |
| ID | Name | Analytic ID | Analytic Description |
|---|---|---|---|
| DET0044 | Detecting Malicious Browser Extensions Across Platforms | AN0123 |
Installation of a new browser extension followed by suspicious file writes or outbound network connections to untrusted domains by the browser process. |
| AN0124 |
Installation of malicious .mobileconfig profiles or browser extension plist entries followed by abnormal browser child process activity. |
||
| AN0125 |
Manual or scripted installation of Chrome extensions using user scripts or config files, followed by unexpected network connections from browser processes. |