PICERL Incident Handling Process – A Comprehensive Guide for GIAC GCIH
Introduction to PICERL Incident Handling
The PICERL model is one of the most foundational frameworks in cybersecurity incident response. It is a six-phase structured approach to handling security incidents, and it is a core topic in the GIAC Certified Incident Handler (GCIH) certification exam. Understanding PICERL thoroughly is essential not only for passing the exam but also for real-world incident response operations.
Why Is PICERL Important?
Incident handling without a structured process leads to chaos, missed evidence, incomplete containment, and recurring breaches. PICERL provides a repeatable, organized methodology that ensures:
• Consistency – Every incident is handled using the same logical steps, reducing human error.
• Completeness – No critical phase is skipped, from initial preparation through post-incident review.
• Legal defensibility – Following a documented process supports forensic integrity and chain-of-custody requirements.
• Organizational learning – The final phase ensures lessons are captured and improvements are made.
• Regulatory compliance – Many compliance frameworks (NIST, ISO 27001, PCI-DSS) expect a formal incident response process aligned with models like PICERL.
What Is PICERL?
PICERL is an acronym representing six sequential phases of incident handling:
P – Preparation
I – Identification
C – Containment
E – Eradication
R – Recovery
L – Lessons Learned
This model is derived from the SANS Institute's incident handling methodology and closely aligns with NIST SP 800-61 (Computer Security Incident Handling Guide), though NIST consolidates some phases differently. For the GCIH exam, you must know the SANS/PICERL version specifically.
How PICERL Works – Phase by Phase
1. Preparation (P)
This is the phase that occurs before any incident takes place. It is widely considered the most important phase because the quality of your preparation directly determines your ability to handle incidents effectively.
Key activities include:
• Developing and maintaining an incident response policy and plan
• Building and training an incident response team (IRT/CSIRT)
• Deploying monitoring tools (SIEM, IDS/IPS, EDR, log aggregation)
• Establishing communication plans (internal and external contacts, escalation paths)
• Creating jump bags and response toolkits (forensic hardware, software, documentation templates)
• Conducting tabletop exercises and simulations
• Ensuring proper network documentation (asset inventories, network diagrams, baselines)
• Setting up secure communication channels for the IR team
• Establishing relationships with law enforcement, ISPs, and external IR firms
Exam Note: The preparation phase is about getting ready. If a question describes activities happening before an incident occurs, the answer is almost always Preparation.
2. Identification (I)
This phase involves detecting that an incident has occurred or may be occurring. It is the transition from normal operations to incident response mode.
Key activities include:
• Monitoring alerts from IDS/IPS, SIEM, antivirus, firewalls, and EDR tools
• Analyzing logs and anomalous behavior
• Receiving reports from users, help desk, or external parties
• Validating and triaging alerts to determine if an event is a true incident or a false positive
• Assigning severity and priority levels
• Documenting the initial findings (who, what, when, where, how)
• Beginning the incident timeline
• Notifying appropriate personnel and stakeholders
Key concept: Not every event is an incident. Identification involves determining whether an event constitutes an actual security incident that warrants a response. This is sometimes referred to as triage.
Exam Note: Questions about detecting, alerting, verifying, or determining whether something is an incident point to the Identification phase.
3. Containment (C)
Once an incident is confirmed, the immediate priority is to prevent it from spreading or causing further damage. Containment limits the scope and impact of the incident.
Key activities include:
• Short-term containment – Immediate actions to stop the bleeding (e.g., isolating a compromised host from the network, blocking a malicious IP at the firewall, disabling a compromised user account)
• Long-term containment – More sustainable measures that allow business operations to continue while the incident is being worked (e.g., moving to a clean VLAN, applying temporary firewall rules, deploying additional monitoring)
• Creating forensic images of affected systems before making changes (critical for evidence preservation)
• Documenting all containment actions taken
Key concept: Containment involves a balance between stopping the incident and preserving evidence. Forensic imaging should ideally occur during containment, before eradication changes the state of the system.
Exam Note: If a question involves isolating systems, blocking traffic, disabling accounts, or preventing lateral movement, the answer is Containment. Also remember: forensic imaging typically happens in the Containment phase – this is a frequently tested point.
4. Eradication (E)
After containment, the root cause and all artifacts of the incident must be removed from the environment.
Key activities include:
• Removing malware, rootkits, backdoors, and unauthorized accounts
• Identifying and addressing the root cause (e.g., patching the exploited vulnerability)
• Rebuilding compromised systems from known-good media if necessary
• Scanning the environment for indicators of compromise (IOCs) to ensure no remnants remain
• Resetting compromised credentials
• Updating detection signatures based on findings
Key concept: Eradication is about removing the threat, not just stopping it. If malware is still present on a system but the system is isolated, you have contained but not eradicated.
Exam Note: If a question asks about removing malware, patching vulnerabilities, deleting attacker tools, or reimaging systems, the answer is Eradication.
5. Recovery (R)
Recovery involves restoring affected systems to normal operations and confirming they are functioning properly and securely.
Key activities include:
• Restoring systems from clean backups or rebuilds
• Bringing systems back online in a controlled, phased manner
• Validating system integrity (checking file hashes, configurations, patch levels)
• Implementing enhanced monitoring on recovered systems to detect any signs of re-compromise
• Monitoring for a defined period to ensure the threat does not recur
• Confirming with system and data owners that operations are restored
Key concept: Recovery is not just turning systems back on. It includes verification and increased monitoring to ensure the incident is truly resolved.
Exam Note: If a question involves restoring from backup, bringing systems back to production, verifying system integrity, or monitoring for reinfection, the answer is Recovery.
6. Lessons Learned (L)
Also known as the post-incident activity or post-mortem phase. This is where the organization reviews what happened and improves its processes.
Key activities include:
• Conducting a formal lessons learned meeting (ideally within two weeks of incident closure)
• Reviewing the complete incident timeline and documentation
• Identifying what went well, what went poorly, and what could be improved
• Updating the incident response plan, policies, and procedures based on findings
• Creating a final incident report
• Sharing relevant threat intelligence with the community (ISACs, CERT, etc.)
• Updating training materials and conducting follow-up exercises
• Addressing any gaps in tools, staffing, or processes
Key concept: This phase feeds back into the Preparation phase, creating a continuous improvement cycle. Without Lessons Learned, the same mistakes are repeated.
Exam Note: If a question involves meetings to discuss what happened, writing final reports, updating policies, or improving future response, the answer is Lessons Learned.
Common Relationships and Distinctions to Remember
• Preparation vs. Lessons Learned: Both involve improving the IR process, but Preparation happens before incidents, while Lessons Learned happens after a specific incident. Lessons Learned feeds into Preparation.
• Containment vs. Eradication: Containment stops the spread; Eradication removes the cause. Isolating a machine is containment. Removing malware from that machine is eradication.
• Eradication vs. Recovery: Eradication removes the bad; Recovery restores the good. Reimaging a system can serve both purposes depending on context, but restoring services to production is Recovery.
• Identification vs. Containment: Identification confirms the incident exists; Containment is the first active response to limit damage.
PICERL vs. NIST SP 800-61 Phases
For exam awareness, NIST uses four phases:
1. Preparation
2. Detection and Analysis (maps to PICERL's Identification)
3. Containment, Eradication, and Recovery (combined into one phase)
4. Post-Incident Activity (maps to Lessons Learned)
The GCIH exam focuses on the six-phase PICERL model, not the NIST four-phase model.
Exam Tips: Answering Questions on PICERL Incident Handling Process
Tip 1: Memorize the Order
The sequence P-I-C-E-R-L is critical. Many questions test whether you know which phase comes before or after another. Use the mnemonic: "Please Inform the Captain that the Enemy has Retreated and Left." Or simply drill the acronym until it is second nature.
Tip 2: Focus on the Action Verb
Read the question carefully and identify the key action being described:
• Planning, training, building tools → Preparation
• Detecting, alerting, verifying, triaging → Identification
• Isolating, blocking, quarantining, imaging → Containment
• Removing, deleting, patching, reimaging → Eradication
• Restoring, rebuilding, monitoring for recurrence → Recovery
• Reviewing, meeting, documenting lessons, updating plans → Lessons Learned
Tip 3: Watch for Forensic Imaging Questions
A classic exam question involves when forensic images should be taken. The correct answer is during the Containment phase – after the incident is identified but before eradication changes the evidence.
Tip 4: Understand the "Most Important Phase" Concept
If asked which phase is the most important or most critical, the expected answer is Preparation. Without adequate preparation, all other phases suffer.
Tip 5: Distinguish Between Similar Phases
The exam often presents scenarios where Containment, Eradication, and Recovery overlap. Ask yourself:
• Is the action stopping the attack? → Containment
• Is the action removing the attacker's artifacts? → Eradication
• Is the action returning to normal operations? → Recovery
Tip 6: Remember the Feedback Loop
Lessons Learned feeds back into Preparation. If a question describes updating the IR plan after an incident, that is Lessons Learned (not Preparation), because it is occurring in the context of a specific post-incident review.
Tip 7: Be Aware of Scenario-Based Questions
GCIH questions often present a scenario and ask "What phase is this?" Read every detail. Look for temporal clues:
• "Before any incident occurs..." → Preparation
• "An analyst notices unusual traffic..." → Identification
• "The team disconnects the server..." → Containment
• "Malware is removed and the vulnerability is patched..." → Eradication
• "Systems are restored from backup and monitored..." → Recovery
• "The team meets to discuss what happened..." → Lessons Learned
Tip 8: Don't Overthink
The GCIH exam tests your ability to correctly categorize activities into the proper PICERL phase. The questions are designed to be clear if you know the framework well. If you find yourself debating between two answers, return to the fundamental definition of each phase and match the primary action described.
Tip 9: Use Your Index Effectively
The GCIH is an open-book exam. Create a dedicated, well-organized index entry for PICERL with page references for each phase, including key activities, definitions, and examples. A quick-reference table mapping actions to phases can save valuable time during the exam.
Tip 10: Practice with Scenario Drills
Before the exam, practice by reading incident handling scenarios and quickly identifying the correct phase. The faster you can classify an activity into the right PICERL phase, the more time you save for harder questions.
Summary Table
Phase → Key Question It Answers
• Preparation → Are we ready to handle an incident?
• Identification → Is this actually an incident?
• Containment → How do we stop it from getting worse?
• Eradication → How do we remove the threat completely?
• Recovery → How do we get back to normal safely?
• Lessons Learned → What can we do better next time?
Mastering PICERL is not just about memorizing six words – it is about understanding the logical flow of incident response and being able to place any given activity into its correct phase with confidence. This understanding is fundamental to the GCIH exam and to effective real-world incident handling.
