Microsoft Blocks Unauthorized Code Injection in Edge

The first platform update for Microsoft Edge, released by the tech giant last week, brings several improvements to the web browser’s rendering engine, including a security feature designed to block unauthorized code injection attempts.

When it announced Edge security improvements in May, Microsoft said it had decided to remove support for legacy technologies and features, including ActiveX, toolbars, VB Script and Browser Helper Objects (BHO), arguing that the rich capabilities of HTML5 significantly reduce the need for such extensions.

The company has improved Edge security even further with the introduction of EdgeHTML 13, the latest version of the web browser’s rendering engine.

While removing support for ActiveX and BHO improves security, toolbars and other unwanted or malicious third-party components can still be installed by injecting dynamic-link libraries (DLLs) into the Edge process.

In an effort to prevent these types of attacks and make browser exploits more difficult to carry out, the latest Edge update blocks DLL injections into the browser process. Only components that are signed by Microsoft and WHQL-signed device drivers will be allowed to load, Microsoft said.

“Code integrity enforcement can be done in the process, or in the kernel. Enforcement in the process is only useful if the threat model is that the process is not yet compromised, because if it has been compromised, then the hacked process can just disable the code integrity check for itself,” explained Crispin Cowan, senior program manager at Microsoft Edge. “Microsoft Edge uses enforcement in the kernel, which is robust against a compromised process, so that even a pernicious ad injector cannot turn off the code integrity check. With the browser process model and the Windows kernel helping each other in this way, Microsoft Edge becomes the first and only PC browser with library content integrity protection.”

Microsoft says there is no such thing as a silver bullet when it comes to browser security, but the company believes the latest improvements will significantly increase the sophistication and expense needed to attack Edge users.

Windows Insider Preview users have benefited from these changes for the past few months and Microsoft says it has seen “tremendous results.”

Earlier this week, at the Microsoft Government Cloud Forum in Washington, D.C., Microsoft CEO Satya Nadella said the company invests more than $1 billion in security research and development every year.

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