Alert - Microsoft Exchange zero-day vulnerabilities - Update 1

Number: AL22-011
Date: 30 September 2022
Updated: 9 November 2022

Audience

This Alert is intended for IT professionals and managers of notified organizations.

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.

Details

On 29 September 2022, Microsoft published an advisory confirming the existence of vulnerabilities impacting Microsoft Exchange^{Footnote 1}. First reported by GTSC Vietnam Technology Services^{Footnote 2}, the vulnerabilities can only be exploited by an authenticated user. Microsoft reports that 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. identified as CVE-2022-41040, is a Server-Side Request Forgery (SSRF) vulnerability, while the second, identified as CVE-2022-41082, allows remote code execution (RCE) when PowerShell is accessible to the malicious actor.

GTSC has reported that these vulnerabilities have been exploited by malicious actors and has resulted in the deployment of webshells as well as information disclosure, command execution and lateral activity.

Update 1

On 8 November 2022, patches for CVE-2022-41040 ^{Footnote 5} and CVE-2022-41082 ^{Footnote 6} were released as part of the November 2022 Security Updates ^{Footnote 7}.

Recommended actions

Microsoft has reported that patches are in development but have confirmed that mitigation recommendations, such as those provided by GTSC, are successful in blocking the activity. Those recommendations are available within both the Microsoft and GTSC advisories ^{Footnote 1Footnote 2Footnote 4}.

As a result of incident response GTSC compiled several Indicators of Compromise CompromiseThe intentional or unintentional disclosure of information, which adversely impacts its confidentiality, integrity, or availability. (IOCs) to aid network defenders in the detection of malicious activity. The Cyber Centre recommends affected customers review the Cyber Centre joint cybersecurity advisory on technical approaches to uncovering and remediating malicious activity ^{Footnote 3}.

The Cyber Centre recommends Exchange customers continue to monitor Microsoft advisory spaces and update systems when a patch is made available.

Should activity matching the content of this Alert be discovered, recipients are encouraged to report via the My Cyber Portal, contact the Cyber Centre by email (contact@cyber.gc.ca), or by telephone (1-833-CYBER-88 or 1-833-292-3788).