T1189: Drive-by Compromise

Adversaries may gain access to a system through a user visiting a website over the normal course of browsing. With this technique, the user's web browser is typically targeted for exploitation, but adversaries may also use compromised websites for non-exploitation behavior such as acquiring Application Access Token.

Multiple ways of delivering exploit code to a browser exist (i.e., Drive-by Target), including:

  • A legitimate website is compromised where adversaries have injected some form of malicious code such as JavaScript, iFrames, and cross-site scripting
  • Script files served to a legitimate website from a publicly writeable cloud storage bucket are modified by an adversary
  • Malicious ads are paid for and served through legitimate ad providers (i.e., Malvertising)
  • Built-in web application interfaces are leveraged for the insertion of any other kind of object that can be used to display web content or contain a script that executes on the visiting client (e.g. forum posts, comments, and other user controllable web content).

Often the website used by an adversary is one visited by a specific community, such as government, a particular industry, or region, where the goal is to compromise a specific user or set of users based on a shared interest. This kind of targeted campaign is often referred to a strategic web compromise or watering hole attack. There are several known examples of this occurring.

Typical drive-by compromise process:

  1. A user visits a website that is used to host the adversary controlled content.
  2. Scripts automatically execute, typically searching versions of the browser and plugins for a potentially vulnerable version.
    • The user may be required to assist in this process by enabling scripting or active website components and ignoring warning dialog boxes.
  3. Upon finding a vulnerable version, exploit code is delivered to the browser.
  4. If exploitation is successful, then it will give the adversary code execution on the user's system unless other protections are in place.
    • In some cases a second visit to the website after the initial scan is required before exploit code is delivered.

Unlike Exploit Public-Facing Application, the focus of this technique is to exploit software on a client endpoint upon visiting a website. This will commonly give an adversary access to systems on the internal network instead of external systems that may be in a DMZ.

Adversaries may also use compromised websites to deliver a user to a malicious application designed to Steal Application Access Tokens, like OAuth tokens, to gain access to protected applications and information. These malicious applications have been delivered through popups on legitimate websites.

Positive Technologies products that cover the technique

MaxPatrol SIEM knowledge base

pt_application_firewall: PT-CR-637: PTAF_Reflected_File_Download_Detected: PT AF detected a reflected file download (RFD) attack

Detection

IDDS0029Data source and componentNetwork Traffic: Network Traffic ContentDescription

Monitor for other unusual network traffic that may indicate additional tools transferred to the system. Use network intrusion detection systems, sometimes with SSL/TLS inspection, to look for known malicious scripts (recon, heap spray, and browser identification scripts have been frequently reused), common script obfuscation, and exploit code.

IDDS0009Data source and componentProcess: Process CreationDescription

Look for behaviors on the endpoint system that might indicate successful compromise, such as abnormal behaviors of browser processes. This could include suspicious files written to disk, evidence of Process Injection for attempts to hide execution, or evidence of Discovery.

IDDS0015Data source and componentApplication Log: Application Log ContentDescription

Firewalls and proxies can inspect URLs for potentially known-bad domains or parameters. They can also do reputation-based analytics on websites and their requested resources such as how old a domain is, who it's registered to, if it's on a known bad list, or how many other users have connected to it before.

IDDS0022Data source and componentFile: File CreationDescription

Monitor for newly constructed files written to disk to gain access to a system through a user visiting a website over the normal course of browsing.

IDDS0029Data source and componentNetwork Traffic: Network Connection CreationDescription

Monitor for newly constructed network connections to untrusted hosts that are used to send or receive data.

Mitigation

IDM1050NameExploit ProtectionDescription

Security applications that look for behavior used during exploitation such as Windows Defender Exploit Guard (WDEG) and the Enhanced Mitigation Experience Toolkit (EMET) can be used to mitigate some exploitation behavior. Control flow integrity checking is another way to potentially identify and stop a software exploit from occurring. Many of these protections depend on the architecture and target application binary for compatibility.

IDM1021NameRestrict Web-Based ContentDescription

For malicious code served up through ads, adblockers can help prevent that code from executing in the first place.

Script blocking extensions can help prevent the execution of JavaScript that may commonly be used during the exploitation process.

IDM1051NameUpdate SoftwareDescription

Ensure all browsers and plugins kept updated can help prevent the exploit phase of this technique. Use modern browsers with security features turned on.

IDM1048NameApplication Isolation and SandboxingDescription

Browser sandboxes can be used to mitigate some of the impact of exploitation, but sandbox escapes may still exist.

Other types of virtualization and application microsegmentation may also mitigate the impact of client-side exploitation. The risks of additional exploits and weaknesses in implementation may still exist for these types of systems.