This week, MSRC confirmed the presence of an active Linux worm leveraging a critical Remote Code Execution (RCE) vulnerability, CVE-2019-10149, in Linux Exim email servers running Exim version 4.87 to 4.91. Azure customers running VMs with Exim 4.92 are not affected by this vulnerability.
Azure has controls in place to help limit the spread of this worm from work we’ve already done to combat SPAM, but customers using the vulnerable software would still be susceptible to infection.
Customers using Azure virtual machines (VMs) are responsible for updating the operating systems running on their VMs. As this vulnerability is being actively exploited by worm activity, MSRC urges customers to observe Azure security best practices and patterns and to patch or restrict network access to VMs running the affected versions of Exim.