Detection & Analysis Stage (Part 2)

1. Understanding the "What" and "How" of an Incident

Purpose: To thoroughly analyze the incident to determine how it occurred, what systems were impacted, and what tools or techniques the adversary used.

• Why: Simply rebuilding impacted systems without understanding the root cause leaves the organization vulnerable to repeat attacks. A detailed analysis ensures that remediation efforts are effective and prevent future compromises.

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2. Why Understanding the Incident Matters

• Rebuilding Without Analysis Risks Repeat Attacks:

  • If the attacker's entry point or methods are not identified, they can exploit the same vulnerabilities again.

  • Example: Reimaging a compromised server without patching the exploited vulnerability allows the attacker to regain access.

• Technical Example:

  • Identify the Attack Vector:

    • Analyze logs to determine how the attacker gained access:

      grep "Failed password" /var/log/auth.log | awk '{print $9}' | sort | uniq -c | sort -nr

      • This command identifies IP addresses with repeated failed login attempts, potentially indicating brute-force attacks.

  • Determine Tools Used by the Attacker:

    • Use forensic tools to identify malicious files or processes:

      lsof -p <PID> # List open files for a suspicious process
      strings /path/to/malicious_file | grep "http"

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3. Analyzing Incident-Related Data

Purpose: To collect and analyze data from various sources to reconstruct the attack timeline and understand the adversary's actions.

• Why: Comprehensive data analysis helps identify all impacted systems, tools used, and the attacker's methodology, enabling targeted remediation.

• Technical Example:

  • Collect Logs from Multiple Sources:

    • Firewall logs:

      grep "DROP" /var/log/firewall.log

    • Endpoint logs (e.g., EDR tools):

      Get-WinEvent -LogName "Microsoft-Windows-Windows Defender/Operational" | Where-Object { $_.Id -eq 1117 }

    • Application logs:

      SELECT * FROM application_logs WHERE event_type = 'ERROR';

  • Correlate Events Across Systems:

    • Use SIEM tools to correlate events and build a timeline:

      index=security_logs src_ip="192.168.1.100" | join transaction_id [search index=endpoint_logs]

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4. Planning Remediation Based on Findings

Purpose: To ensure that remediation efforts address the root cause and close off all attack paths.

• Why: Effective remediation prevents the attacker from reusing the same techniques or exploiting the same vulnerabilities.

• Technical Example:

  • Patch Vulnerabilities:

    • Identify and apply patches for exploited vulnerabilities:

      sudo apt-get update && sudo apt-get upgrade

    • Use tools like Qualys or Nessus to verify patch application:

      nessuscli agent status

  • Block Attacker IPs:

    • Update firewall rules to block known malicious IPs:

      iptables -A INPUT -s <ATTACKER_IP> -j DROP

  • Remove Malicious Artifacts:

    • Delete malicious files and terminate suspicious processes:

      rm /path/to/malicious_file
      kill -9 <PID>

  • Harden Systems:

    • Implement security best practices to reduce the attack surface:

      Set-NetFirewallRule -DisplayName "Block SMB" -Enabled True

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5. Ensuring the Attack Path Cannot Be Replicated

Purpose: To validate that the attacker's methods cannot be reused after remediation.

• Why: Closing off all possible attack vectors ensures long-term protection and reduces the likelihood of repeat incidents.

• Technical Example:

  • Test for Residual Vulnerabilities:

    • Use penetration testing tools like Metasploit to verify that the vulnerability has been mitigated:

      msfconsole -q -x "use exploit/windows/smb/ms17_010_eternalblue; set RHOSTS 192.168.1.100; run"

  • Monitor for Recurrence:

    • Deploy detection rules to alert on similar activity in the future:

      index=security_logs action="login_failed" | stats count by src_ip

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Conclusion

Understanding the "what" and "how" of an incident is critical to ensuring effective remediation. By analyzing logs, identifying the attacker's methods, and addressing the root cause, organizations can close off attack paths and prevent repeat compromises.

This approach not only resolves the immediate issue but also strengthens the organization's overall security posture. Regular monitoring and testing further ensure that remediation efforts are successful and that the attacker cannot regain access.