Initial Impact Assessment Techniques

Description: Forensically investigating the impact of a compromise on workstations and server systems is an essential step in understanding the extent of damage, the data affected, and what steps are necessary for recovery and future prevention. This process involves thoroughly examining affected systems to identify the scope of the attack, assess the damage, and uncover the methods used by the attackers.

1. Understanding Possible Impacts

• Data Exfiltration: Determining if sensitive data was accessed or stolen.

• Data Destruction: Assessing if any data was deleted or corrupted.

• System Compromise: Evaluating the integrity of the operating system and critical software.

• Service Disruption: Identifying if key services were disrupted or disabled.

• Persistence: Checking for any signs that the attacker has established ongoing access.

• Lateral Movement: Investigating whether the compromise spread to other systems in the network.

2. Data Collection and Preservation

• Forensic Imaging: Use tools like FTK Imager or dd to create exact copies of affected systems' hard drives.

• Memory Capture: Use tools like Magnet RAM Capture or WinPmem to capture volatile memory.

• Log Collection: Secure all relevant logs, including system logs, application logs, security logs, and network logs.

3. Assessing Data Exfiltration

• Network Traffic Analysis: Use tools like Wireshark or Tcpdump to analyse network traffic for signs of data being sent to external locations.

• Log Analysis: Check firewall, web proxy, and server logs for unusual outbound traffic.

4. Evaluating Data Integrity

• File System Analysis: Examine the file system for signs of deletion, alteration, or encryption of files.

• Data Recovery Techniques: Use data recovery tools to attempt to restore deleted or corrupted files.

5. System Compromise Assessment

• Malware Analysis: Look for and analyse any malware that may have been used in the attack.

• Rootkit Detection: Employ rootkit detection tools to uncover any stealthy malware or tools used by the attackers.

• Integrity Checks: Run integrity checks on critical system files and configurations.

6. Service Disruption Analysis

• System and Application Logs: Review these logs for service stop events, crashes, or configuration changes that could indicate sabotage.

• Dependency Checks: Ensure critical services and applications function properly and depend on uncompromised components.

7. Investigating Persistence Mechanisms

• Startup Items: Check for unauthorised scripts or programs in startup locations.

• Scheduled Tasks and Cron Jobs: Look for tasks that may provide ongoing access or trigger malicious activities.

• Registry (Windows): Examine registry keys commonly used for persistence.

8. Lateral Movement Investigation

• Active Directory and Network Logs: Analyse these logs for signs of credential use on multiple systems.

• Endpoint Detection and Response (EDR) Data: Review EDR data for patterns that suggest movement across the network.

9. Documentation and Reporting

• Detailed Documentation: Keep a comprehensive record of all findings, methodologies, and evidence paths.

• Impact Report: Prepare a detailed report summarising the impact, including data loss, system integrity issues, and business disruption.

10. Post-Investigation Actions

• Remediation and Mitigation: Implement necessary measures to recover data, restore services, and secure the network.

• Incident Review and Policy Update: Conduct a thorough review of the incident to improve future security posture and incident response capabilities.

11. ols and Techniques

• Digital Forensics:

  • Specialised tools for evidence collection and analysis:

    • OpenText EnCase Forensics (commercial tool)

    • FTK (Forensic Toolkit)

    • Volatility (memory forensics)

    • Autopsy (open-source)

    • Cyber Triage (commercial tool)

    • Binalyze AIR (commercial tool)

    • Belkasoft (commercial tool)

    • Oxygen Forensics (commercial tool)

    • X-ways Forensics (commercial tool)

    • The Sleuth Kit (open-source tool)

    • Eric Zimmerman Tools (open-source tool)

  • Techniques include timeline analysis, file recovery, and reverse engineering.

• Incident Response:

  • Tools for monitoring, containment, and eradication:

    • SIEM (Splunk, QRadar, Microsoft Sentinel, Sumo Logic, Graylog, Elastic Security, LogRhythm, Datadog, Exabeam)

    • EDR (CrowdStrike, SentinelOne, Defender for Endpoint, Cortex XDR, FortiEDR)

    • Firewalls and IDS/IPS systems

  • Techniques include log analysis, threat containment, and system restoration.

12. Key Considerations

• Legal and Compliance Factors: Ensure the investigation complies with legal and regulatory requirements.

• Chain of Custody: Maintain an accurate chain of custody for all forensic evidence.

• Confidentiality: Handle all data securely, maintaining confidentiality and integrity throughout the process.

Forensic investigations into the impact of a compromise require a multi-faceted approach, combining technical analysis with an understanding of business operations and data sensitivity. Tailoring the investigation to the specifics of the incident and the environment is essential for a comprehensive assessment.