The first thing that the information security manager should do after reading about a vendor product compromise on social media is to validate the risk to the organization. This means verifying the source and credibility of the information, determining if the organization uses the affected product, and assessing the potential impact and likelihood of the compromise on the organization's data and systems. Validating the risk to the organization will help the information security manager to decide on the appropriate course of action, such as activating the incident response program, notifying relevant stakeholders, or performing a BIA.
References: The CISM Review Manual 2023 states that "the information security manager is responsible for identifying and assessing the risks associated with the use of third-party products and services" and that "the information security manager should monitor and review the security performance and incidents of third-party products and services on a regular basis and take corrective actions when deviations or violations are detected" (p. 138). The CISM Review Questions, Answers & Explanations Manual 2023 also provides the following rationale for this answer: "Validating the risk to the organization is the correct answer because it is the first and most important step to take after reading about a vendor product compromise on social media, as it will help the information security manager to confirm the accuracy and relevance of the information, and to evaluate the potential consequences and probability of the compromise on the organization's data and systems" (p. 63). Additionally, the article Defending Against Software Supply Chain Attacks from the CISA website states that "the first step in responding to a software supply chain attack is to validate the risk to the organization by verifying the source and credibility of the information, determining if the organization uses the affected software, and assessing the potential impact and likelihood of the compromise on the organization's data and systems" (p. 2)