Microsoft security advisory

Number: AV19-115
Date: 12 June 2019

Microsoft has released security updates to address multiple vulnerabilities, including 21 critical vulnerabilities, affecting some Microsoft products. Of note are two vulnerabilities in Microsoft’s NT LAN Manager (NTLM) authentication AuthenticationA process or measure used to verify a users identity. protocol that affect all versions of Windows. In the first vulnerability VulnerabilityA flaw or weakness in the design or implementation of an information system or its environment that could be exploited to adversely affect an organization's assets or operations. , researchers were able to bypass several security features of the protocol to allow an actor to relay NTLM authentication requests to any computer on the domain, allowing for remote code execution in the context of the signed NTLM session. This flaw could prove to be especially dangerous if the actor were able to relay the authentication of a privileged user. The second vulnerability allows an actor to relay NTLM messages to secure web (TLS) sessions. An actor could leverage this flaw to authenticate to online Microsoft services such as Outlook Web Access, in the context of the relayed NTLM session.

CCCS encourages users and administrators to review the Microsoft June 2019 Security Updates webpage and apply the necessary updates:

https://portal.msrc.microsoft.com/en-us/security-guidance/releasenotedetail/253dc509-9a5b-e911-a98e-000d3a33c573

Note to Readers

The Canadian Centre for Cyber Security Cyber securityThe protection of digital information, as well as the integrity of the infrastructure housing and transmitting digital information. More specifically, cyber security includes the body of technologies, processes, practices and response and mitigation measures designed to protect networks, computers, programs and data from attack, damage or unauthorized access so as to ensure confidentiality, integrity and availability. (Cyber Centre) operates as part of the Communications Security Establishment. We are Canada’s national authority on cyber security and we lead the government’s response to cyber security events. As Canada's national computer security incident response team, the Cyber Centre works in close collaboration with government departments, critical infrastructure Critical infrastructureProcesses, systems, facilities, technologies, networks, assets, and services essential to the health, safety, security, or economic well-being of Canadians and the effective functioning of government. Critical infrastructure can be stand-alone or interconnected and interdependent within and across provinces, territories, and national borders. Disruptions of critical infrastructure could result in catastrophic loss of life, adverse economic effects, and significant harm to public confidence. , Canadian businesses and international partners to prepare for, respond to, mitigate, and recover from cyber events. We do this by providing authoritative advice and support, and coordinating information sharing and incident response. The Cyber Centre is outward-facing, welcoming partnerships that help build a stronger, more resilient cyber space in Canada.