For the second time in a week, hackers have discovered a previously unknown bug in Microsoft’s Internet Explorer (IE) browser that could be exploited to run unauthorized software on a Windows computer. This latest bug, reported Thursday, could be exploited to seize control of a Windows system and has been given a “high risk” rating by the FrSIRT security website.Although “proof-of-concept” code showing how this vulnerability could be exploited has been published, making the bug a more serious concern, there are some mitigating factors. Attackers would first need to trick users into visiting a specially coded webpage and then somehow get them to perform certain actions, such as writing “specific text in a text field,” before they could run their malicious software, FrSIRT said. The risk is further mitigated by the fact that the bug reportedly does not affect the latest versions of Microsoft’s Windows and Windows Server 2003 operating systems, FrSIRT said. Because of these mitigating factors, Microsoft has decided not to fix the bug in a security update to Internet Explorer. “The vulnerability cannot be used to execute code on a user’s system without multiple user actions that are uncommon in typical Web browsing scenarios,” Microsoft said in a statement provided by its public relations agency. “Due to the significant mitigating factors … we have determined that the issue would be most appropriately addressed in a service pack delivery rather than a security update.” Microsoft is not aware of any attacks made so far that were intended to exploit the vulnerability, the statement said.Users who do not want to wait for the next IE service pack can avoid problems by changing IE’s security settings so that the browser no longer prompts users before delivering active content, said Matthew Murphy, the researcher who discovered the bug. “The vulnerability at issue depends fundamentally on a weakness in the browser’s method of prompting when warning users of potentially unsafe active content on a Web page,” he said in a full-disclosure mailing list posting.This workaround may prevent IE from working properly on websites that depend on ActiveX controls, however, he warned.Internet Explorer continues to be a prime target for attackers, with Microsoft having to patch a handful of publicly disclosed bugs in its latest security update for the product, which was released April 11.Last Sunday, researcher Michael Zalewski posted details of a similarly critical bug in IE to Full Disclosure. Security firm Secunia rates Zalewski’s bug as “highly critical.”Microsoft was not immediately available for comment on this latest vulnerability. — Robert McMillan, IDG News ServiceThis article is posted on our Microsoft Informer page. For more news on the Redmond, Wash.-based powerhouse, keep checking in.For related coverage, read Firefox Supporters Set Sights on Internet Explorer With Campaign and Microsoft Debuts New Internet Explorer Beta.Check out our CIO News Alerts and Tech Informer pages for more updated news coverage. Related content opinion Website spoofing: risks, threats, and mitigation strategies for CIOs In this article, we take a look at how CIOs can tackle website spoofing attacks and the best ways to prevent them. By Yash Mehta Dec 01, 2023 5 mins CIO Cyberattacks Security brandpost Sponsored by Catchpoint Systems Inc. Gain full visibility across the Internet Stack with IPM (Internet Performance Monitoring) Today’s IT systems have more points of failure than ever before. Internet Performance Monitoring provides visibility over external networks and services to mitigate outages. By Neal Weinberg Dec 01, 2023 3 mins IT Operations brandpost Sponsored by Zscaler How customers can save money during periods of economic uncertainty Now is the time to overcome the challenges of perimeter-based architectures and reduce costs with zero trust. By Zscaler Dec 01, 2023 4 mins Security feature LexisNexis rises to the generative AI challenge With generative AI, the legal information services giant faces its most formidable disruptor yet. That’s why CTO Jeff Reihl is embracing and enhancing the technology swiftly to keep in front of the competition. By Paula Rooney Dec 01, 2023 6 mins Generative AI Digital Transformation Cloud Computing Podcasts Videos Resources Events SUBSCRIBE TO OUR NEWSLETTER From our editors straight to your inbox Get started by entering your email address below. Please enter a valid email address Subscribe