Microsoft patches actively exploited Internet Explorer flaw

The Internet Explorer icon as seen on a smartphone in behind a screen with lines of code

(Image credit: Shutterstock)

Microsoft has fixed dozens of security flaws across its suite of products, including a critical Internet Explorer bug that’s been previously exploited by state-backed North Korean hackers to attack security researchers.

The flaw, tracked as CVE-2021-26411, is a memory corruption vulnerability that’s allowed hackers to run malware on victims’ machines by luring them into accessing a malicious website.

This is the fifth actively exploited Microsoft vulnerability to be patched in recent weeks, after four Microsoft Exchange Server flaws were disclosed last week.

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These five fixes were included in the latest Patch Tuesday wave of updates among 89 patches across Microsoft products, including fixes for 14 critically-rated vulnerabilities.

The latest actively-exploited remote code exploitation flaw affects Internet Explorer versions 9 and 11, as well as the HTML-based Microsoft Edge, which itself reached end-of-life today. Internet Explorer will stop being supported with updates from 17 August this year.

The Internet Explorer vulnerability was previously reported as a zero-day by the South Korean security firm Enki in February, which itself was targeted by hackers exploiting the bug.

To trigger the exploit, an attacker would first have to craft a website, or take advantage of a compromised website and convince a user to view it. This would usually be done by undergoing a phishing exercise, either by sending an email or text message or prompting users to download a malicious email attachment.

The discovery of a sixth actively-exploited flaw in recent weeks is sure to raise alarms considering the potentially devastating effects that the recent Microsoft Exchange Server exploitation has rendered.

The White House weighed in over the weekend, advising businesses to patch their systems immediately due to the risk of intrusion, with security researchers warning there could be hundreds of thousands of prospective victims across the world. One organisation that’s among the first confirmed victims of the attacks is the European Banking Authority.

Keumars Afifi-Sabet is a writer and editor that specialises in public sector, cyber security, and cloud computing. He first joined ITPro as a staff writer in April 2018 and eventually became its Features Editor. Although a regular contributor to other tech sites in the past, these days you will find Keumars on LiveScience, where he runs its Technology section.