Alert - Internet Explorer Security Alert

Number: AL18-17
Date: 19 December 2018

Purpose

An ALERT is used to raise awareness of a recently identified cyber threat Cyber threatA threat actor, using the internet, who takes advantage of a known vulnerability in a product for the purposes of exploiting a network and the information the network carries. that may impact cyber information assets, and to provide additional detection DetectionThe monitoring and analyzing of system events in order to identify unauthorized attempts to access system resources. and mitigation advice to recipients. (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") is also available to provide additional assistance regarding the content of this ALERT to recipients as requested.)

Assessment

The goal of this Alert is to bring heightened attention to a 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 Internet Explorer for which there is currently a patch available. The vulnerability can be exploited by deceiving an end user into opening a maliciously-crafted website. Exploitation can lead to remote code execution on the affected computer. There are reports of this exploit currently being used in the wild.

Internet Explorer 9 to 11 on Windows 7 to 10, Server 2008 to 2019, and RT 8.1 are affected. Server editions which run IE in restricted (Enhanced Security Configuration) mode will not allow this vulnerability to be exploited unless the server website is added to the Internet Explorer Trusted sites zone.

CVE reference: CVE-2018-8653

Suggested action

  • The Cyber Centre recommends that organizations update Internet Explorer as soon as possible.
  • Do not open links to unknown websites.
  • Do not browse the internet while logged in with a high privilege account such as Administrator.
  • Do not disable Enhanced Security Configuration mode in Internet Explorer on Windows Servers.
  • Ensure only validated, necessary sites are added to the Internet Explorer Trusted sites zone.

References

Microsoft Security Bulletin: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8653

Note to readers

The Canadian Centre for Cyber Security (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.

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