How do you investigate a security incident in a SOC?

Investigating a security incident in a SOC (Security Operations Center) is a systematic process that involves several key steps to understand the nature, scope, and impact of the incident, as well as to devise appropriate containment and remediation strategies. Here's a general approach to investigating a security incident:

1. Incident Triage: Begin by assessing the severity and credibility of the incident. Determine the urgency of the response based on factors like the type of data affected, the systems involved, and the potential impact on the organization.
2. Assemble the Incident Response Team: Activate the incident response team based on the nature and scope of the incident. This team typically includes security analysts, IT staff, legal advisors, and communication specialists.
3. Secure the Evidence: Before proceeding with further steps, ensure that evidence is preserved in a manner that maintains its integrity. This might involve capturing network traffic, securing logs, and making forensic copies of affected systems.
4. Containment: Implement immediate measures to contain the incident and prevent further damage or data loss. This could involve isolating affected network segments, taking compromised systems offline, or blocking malicious communication.
5. Detailed Analysis: Conduct an in-depth analysis of the incident to understand how the breach occurred, the extent of the impact, and the tactics, techniques, and procedures (TTPs) used by the attackers. Analyze logs, system artifacts, network traffic, and other relevant data sources.
6. Identification of Compromised Systems and Data: Identify which systems and data were compromised to assess the full impact of the incident. This will inform the recovery process and help in determining the notification requirements.
7. Eradication: Once the analysis is complete, remove the threat from the environment. This includes eradicating malware, closing exploited vulnerabilities, and ensuring that the attackers no longer have access to the systems.
8. Recovery: Restore affected systems and services to normal operation, ensuring they are no longer compromised. Monitor the systems for any signs of persistence or recurrence of the threat.
9. Communication: Maintain clear and timely communication with stakeholders, including management, affected users, and potentially external parties (such as customers or regulatory bodies), in accordance with the organization's communication plan and legal requirements.
10. Post-Incident Review: After the incident is resolved, conduct a thorough review to evaluate the response's effectiveness and identify lessons learned. Discuss what worked well, what could have been done better, and how the organization can improve its security posture and incident response processes.
11. Update Incident Response Plan: Use the insights gained from the review to update the incident response plan, enhancing procedures and protocols based on the lessons learned.

Throughout this process, it's crucial to maintain detailed documentation of the incident response actions, decisions, and findings. This documentation is essential for post-incident reviews, compliance purposes, legal considerations, and for improving future incident response efforts.