The vulnerability is being used in online attacks, the U.S. Computer Emergency Response Team said Security vendors are warning users of Microsoft’s Internet Information Services 6 Web-server software that a new online attack could put their data at risk.The flaw was made public Thursday, when security researcher Nikolaos Rangos posted details of the vulnerability to the Full Disclosure security mailing list. By sending a specially crafted HTTP request to the server he was able to view and upload files on the machine. The attack takes advantage of a bug in the way that Microsoft’s software processes Unicode tokens, he said.The vulnerability is being used in online attacks, the U.S. Computer Emergency Response Team said Monday.In a statement, Microsoft said it hadn’t heard of any such attacks, but that it was investigating Rangos’ claims. “We are working on a security advisory to provide customers with guidance,” the company said Monday. The bug affects IIS 6 users who have enabled the WebDAV (Web-based Distributed Authoring and Versioning) protocols, used to share documents via the Web.It gives attackers a way to view protected files on the server without authorization and it could be used to upload files as well, according to Thierry Zoller, an independent security researcher who confirmed Rangos’ findings. However, Zoller said he had found no way to use this flaw to run unauthorized software on an IIS server. Zoller said that IIS 5 and IIS 7 do not appear to be vulnerable to the attack, but that it could affect other Microsoft products that use the WebDAV technology. “Better safe than sorry,” he said via instant message, “Disable WebDAV temporarily and wait for Microsoft to patch.”In an e-mail interview, Rangos said that even with WebDAV enabled, Exchange Server running on IIS 6 and SharePoint Server were not affected by the flaw.Cisco sounded a similar warning. “Administrators of sites that are hosting sensitive information on IIS servers that use WebDAV are advised to put effective mitigations into place immediately because exploit code is publicly available,” the company said in a security alert posted to its Web site. Related content feature Top cybersecurity M&A deals for 2023 Fears of recession, rising interest rates, mass tech layoffs, and conservative spending trends are likely to make dealmakers cautious, but an ever-increasing need to defend against bigger and faster attacks will likely keep M&A activity steady in By CSO Staff Sep 22, 2023 24 mins Mergers and Acquisitions Mergers and Acquisitions Mergers and Acquisitions brandpost Unmasking ransomware threat clusters: Why it matters to defenders Similar patterns of behavior among ransomware treat groups can help security teams better understand and prepare for attacks By Joan Goodchild Sep 21, 2023 3 mins Cybercrime news analysis China’s offensive cyber operations support “soft power” agenda in Africa Researchers track Chinese cyber espionage intrusions targeting African industrial sectors. By Michael Hill Sep 21, 2023 5 mins Advanced Persistent Threats Cyberattacks Critical Infrastructure brandpost Proactive OT security requires visibility + prevention You cannot protect your operation by simply watching and waiting. It is essential to have a defense-in-depth approach. By Austen Byers Sep 21, 2023 4 mins Security 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