Building 92 at Microsoft's headquarters in Redmond, Washington. (Coolcaesar via CC BY-SA 4.0)

Microsoft antivirus tools many users already have installed will now automatically mitigate a critical Exchange Server vulnerability, the lynchpin of several recent campaigns to breach on-premises servers.

On Thursday evening, Microsoft announced up-to-date Microsoft Defender Antivirus and System Center Endpoint Protection will now mitigate CVE-2021-26855, one of a chain of four vulnerabilities Microsoft observed hackers exploiting in the wild. While all four were patched earlier this month, and the comprehensive solution is to still install all patches patch, hackers' current playbook is to use CVE-2021-26855 to set up the other three. Blocking that one vulnerability snips the first link in the chain.

Please register to continue.

Already registered? Log in.

Once you register, you'll receive:

  • News analysis

    The context and insight you need to stay abreast of the most important developments in cybersecurity. CISO and practitioner perspectives; strategy and tactics; solutions and innovation; policy and regulation.

  • Archives

    Unlimited access to nearly 20 years of SC Media industry analysis and news-you-can-use.

  • Daily Newswire

    SC Media’s essential morning briefing for cybersecurity professionals.

  • Learning Express

    One-click access to our extensive program of virtual events, with convenient calendar reminders and ability to earn CISSP credits.