Alert - Critical Microsoft Remote Desktop Vulnerability

Number: AL19-009
Date: 14 May 2019

PURPOSE

An Alert is used to raise awareness of a recently disclosed Remote Code Execution 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. in the Microsoft Remote Desktop Services platform.

ASSESSMENT

Microsoft has released patches for a critical vulnerability in Microsoft Remote Desktop Services (RDS). The vulnerability allows a remote, unauthenticated actor to run arbitrary code on some Microsoft operating systems running RDS. This vulnerability is ‘wormable’, meaning that exploits of this vulnerability could automatically propagate from one vulnerable system to another.

The vulnerable operating systems are:

  • Windows 7 for 32-bit Systems Service Pack 1
  • Windows 7 for x64-based Systems Service Pack 1
  • Windows Server 2008 for 32-bit Systems Service Pack 2
  • Windows Server 2008 for 32-bit Systems Service Pack 2
  • Windows Server 2008 for Itanium-Based Systems Service Pack 2
  • Windows Server 2008 for x64-based Systems Service Pack 2
  • Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
  • Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1
  • Windows Server 2008 R2 for x64-based Systems Service Pack 1
  • Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
  • Windows XP SP3 x86
  • Windows XP Professional x64 Edition SP2
  • Windows XP Embedded SP3 x86
  • Windows Server 2003 SP2 x86
  • Windows Server 2003 x64 Edition SP2

SUGGESTED ACTION

  • Install the latest updates for the vulnerable operating systems.
  • Disable Remote Desktop Services if not required. If required, closely monitor network traffic and the logs of any vulnerable systems for suspicious activity.
  • Enable Network Level Authentication (NLA) on systems running Windows 7, Windows Server 2008, and Windows Server 2008 R2. This is a partial mitigation which will prevent the spread of the malware.
  • Block TCP port 3389 on the firewall, if possible. This will prevent unauthorized access from the Internet.

REFERENCES

Microsoft advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0708

Microsoft advisory for legacy operating systems (Windows XP and Server 2003): https://support.microsoft.com/en-ca/help/4500705/customer-guidance-for-cve-2019-0708

Microsoft blog post: https://blogs.technet.microsoft.com/msrc/2019/05/14/prevent-a-worm-by-updating-remote-desktop-services-cve-2019-0708/

NOTE TO READERS

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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
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