Microsoft hopes to fix by May 8 a critical flaw in Windows DNS servers that is being exploited by online criminals, the company said late Tuesday.Microsoft has been under pressure to address the flaw, reported last week, since software that exploits it has now been widely disseminated, and criminals are beginning to use it in attacks. On Monday, security experts confirmed that variants of the Rinbot worm (also called Nirbot by some vendors) had been scanning networks for vulnerable systems and then attempting to exploit the DNS bug.Microsoft characterizes the level of attacks as “not widespread.”The problem affects Windows 2000 and Windows Server 2003 systems, which can be tricked into running unauthorized software when an attacker sends them maliciously encoded Remote Procedure Call (RPC) packets to the DNS server. The latest versions of Windows 2000 Professional, XP and Vista are not vulnerable to this attack. Microsoft has published a workaround for the problem, and the software vendor is weighing whether to step up its response and fix it ahead of May 8, the date of the company’s next scheduled security update.“While we don’t have a firm estimate on when we’ll complete our development and testing of updates for this issue, we have teams around the world working on it twenty-four hours a day, and hope to have updates no later than May 8, 2007,” wrote Microsoft security program manager Christopher Budd in a Tuesday blog posting. “However, this is a developing situation and we are constantly evaluating the situation and the status of our development and testing of updates.” Microsoft was in a similar situation three weeks ago when attackers began exploiting a similarly critical flaw in the software used by Windows to read animated cursor files. Ultimately, Microsoft was forced to release an early patch for that problem. -Robert McMillan, IDG News Service 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