CrowdStrike has developed the Log4j Quick Reference Guide (QRG) to help organizations understand and mitigate the risks associated with the Log4j vulnerability, which has become a significant concern for security teams due to its evolving nature. The guide, based on a combination of open-source research and proprietary insights from CrowdStrike's extensive experience with real-world intrusions, offers a comprehensive overview of the vulnerability's trajectory, potential impacts, and recommended mitigation strategies. Additionally, it provides best practices for testing vulnerable systems and encourages frequent updates as new insights emerge. Alongside the guide, CrowdStrike is hosting a webcast to share observations from incident response engagements and introduce the CrowdStrike Archive Scanning Tool (CAST), designed to help organizations assess their exposure to the Log4j vulnerability.