Microsoft has overhauled the Internet Explorer mode in Edge after reports of active exploitation allowed attackers to hijack user devices.
Quick Summary – TLDR:
- Microsoft revamped Edge’s IE Mode after hackers abused it to exploit zero-day flaws in the Chakra engine
- Attackers tricked users into reloading sites in IE Mode, bypassing modern browser protections
- Microsoft removed all quick-access buttons and menus for IE Mode to reduce attack risks
- IE Mode is now only accessible through deeper browser settings and manual site allowlisting
What Happened?
Microsoft received credible reports in August 2025 that hackers were exploiting Internet Explorer (IE) Mode in Edge to run malicious code and take full control of user systems. The attackers used social engineering to lure users into activating the outdated IE environment where modern security protections are not in place.
⚠️ Microsoft tightens Edge’s IE mode after exploit reports#Microsoft says attackers used social engineering plus unpatched Chakra 0day to trick users into reloading pages in IE mode, achieve RCE and privilege escalation. Edge removed quick IE controls; IE mode must now be… pic.twitter.com/VYVleGctNs
— ransomNews (@ransomnews) October 13, 2025
Microsoft Reacts to IE Mode Abuse
IE Mode was initially introduced in Edge to provide backward compatibility for older websites that still rely on legacy technologies. While convenient for enterprise and government portals, it also reopens the door to Internet Explorer’s outdated architecture, specifically the Chakra JavaScript engine, which lacks modern browser protections.
Microsoft’s Browser Vulnerability Research team confirmed that attackers:
- Created fake, legitimate-looking websites.
- Used a flyout prompt to convince users to reload pages in IE Mode.
- Leveraged a zero-day exploit in Chakra to execute remote code.
- Followed with a privilege escalation to take full control of the victim’s system.
This tactic effectively bypassed modern browser sandboxes, giving attackers the power to deploy malware, move laterally across networks, and exfiltrate sensitive data.
Major Security Changes Rolled Out
To respond swiftly, Microsoft made several significant changes to tighten access to IE Mode. These include:
- Removing the “Reload in IE Mode” button from the Edge toolbar.
- Disabling right-click menu options that launch IE Mode.
- Eliminating the hamburger (main) menu shortcut for IE Mode.
These updates apply to non-enterprise users. Businesses using Edge with Group Policy or Microsoft Intune can still configure IE Mode for essential apps, but with more scrutiny.
Now, to access IE Mode, users must:
- Go to Settings > Default Browser.
- Enable “Allow sites to be reloaded in Internet Explorer mode”.
- Manually add specific URLs to the IE Mode site list.
- Restart the browser and reload the page.
According to Microsoft, these extra steps are designed to slow down attackers, making it harder for them to trick users into enabling IE Mode casually. As Microsoft put it, “the decision to load web content using legacy technology is significantly more intentional” with these changes in place.
Why IE Mode Remains a Risk?
IE Mode uses an older version of the Chakra JavaScript engine, which lacks security hardening features now standard in Chromium-based browsers like Edge and Chrome. This makes it a prime target for exploits, especially in environments where users may not know they’re activating insecure features.
Although IE Mode is still crucial for many enterprise-grade systems and government tools, Microsoft strongly encourages users and organizations to migrate away from legacy web technologies.
What Users Should Do?
If you’re a user or IT admin still relying on IE Mode:
- Review which sites are allowed to open in IE Mode.
- Ensure only trusted domains are added to the site list.
- Consider transitioning away from legacy apps or websites to more secure, modern alternatives.
IE 11 officially reached end of life on June 15, 2022, and Edge is now Microsoft’s sole supported browser moving forward.
SQ Magazine’s Takeaway
I think this is a bold and necessary move by Microsoft. While IE Mode helped ease the transition to modern browsers, it clearly became a serious vulnerability waiting to be exploited. I appreciate that Microsoft didn’t just slap on a patch but completely restructured how IE Mode works, making it harder for hackers to abuse it. If you’re still using IE Mode, it’s time to re-evaluate whether you really need it. These legacy tools are just too risky in today’s threat landscape.
