Incident Response & Digital Forensics

Incident Response & Digital Forensics

Purpose

Enable Claude to assist with structured incident response operations following NIST SP 800-61 and the SANS PICERL framework. Claude generates IR playbooks, guides evidence collection with chain of custody, constructs forensic timelines, interprets memory forensics output, and produces post-incident reports.

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Activation Triggers

This skill activates when the user asks about:

• Creating an incident response playbook (ransomware, phishing, breach, etc.)
• Evidence collection and chain of custody procedures
• Forensic timeline construction from logs or artifacts
• Memory forensics using Volatility
• Post-incident report generation
• DFIR (Digital Forensics and Incident Response) procedures
• Containment and eradication strategies
• Root cause analysis for security incidents
• IR metrics, SLA tracking, or reporting for management

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Prerequisites

pip install pyyaml jinja2 pandas python-dateutil

Recommended DFIR tools:

• Volatility 3 — Memory forensics framework
• Autopsy / Sleuth Kit — Disk forensics
• plaso / log2timeline — Supertimeline generation
• KAPE — Evidence collection (Windows)
• Velociraptor — Enterprise-scale endpoint forensics
• FTK Imager — Forensic imaging (Windows)
• dd / dcfldd / dc3dd — Disk imaging (Linux)

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PICERL Framework Overview

Every IR engagement follows the PICERL lifecycle:

| Phase | Key Actions | Skill Outputs | |-------|------------|---------------| | Preparation | Verify tools, comms, access | Readiness checklist | | Identification | Confirm incident, scope, severity | Incident classification | | Containment | Isolate systems, stop spread | Containment actions list | | Eradication | Remove threat, close access | Eradication checklist | | Recovery | Restore systems, verify integrity | Recovery runbook | | Lessons Learned | Post-incident review | IR report + improvements |

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Core Capabilities

1. IR Playbook Creation

When the user asks to create a playbook for a specific incident type:

Claude generates detailed, role-assigned playbooks in this structure:

Ransomware Response Playbook (Example):

# IR Playbook: Ransomware Attack
Version: 2.0 | Owner: SOC Manager | Review: Quarterly

## Trigger Conditions
- Multiple encrypted files discovered (ransom extension detected)
- Ransom note found on file shares or desktop
- EDR alert for mass file modification activity
- User reports files inaccessible with unfamiliar extensions

## Severity Classification
- CRITICAL: Domain controller / backup infrastructure affected
- HIGH: Production servers / business-critical data affected
- MEDIUM: Isolated workstation, contained environment

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## Phase 1: Identification (Target: 15 minutes)
**IR Lead:**
- [ ] Confirm incident is ransomware (verify encrypted files + ransom note)
- [ ] Determine initial infection vector (phishing? RDP? Supply chain?)
- [ ] Identify Patient Zero — first encrypted system
- [ ] Assess scope: How many systems? Which business units?
- [ ] Declare incident severity and notify stakeholders
- [ ] Open incident ticket and begin documentation

**Forensics:**
- [ ] DO NOT REBOOT infected systems (preserve volatile evidence)
- [ ] Capture memory dump: `winpmem_mini_x64_rc2.exe output.raw`
- [ ] Collect running processes: `tasklist /v > processes.txt`
- [ ] Collect network connections: `netstat -ano > netstat.txt`

## Phase 2: Containment (Target: 30 minutes)
**Network Team:**
- [ ] Isolate affected systems (pull network cable or quarantine in VLAN)
- [ ] Block identified C2 IPs/domains at perimeter firewall
- [ ] Disable RDP externally if RDP was the initial vector
- [ ] Preserve network capture if encryption is still occurring

**Active Directory:**
- [ ] Identify all accounts used by the ransomware (service accounts, domain accounts)
- [ ] Reset passwords for all potentially compromised accounts
- [ ] Revoke active sessions for affected accounts
- [ ] Check for newly created privileged accounts

## Phase 3: Eradication
- [ ] Identify all persistence mechanisms (registry, services, scheduled tasks)
- [ ] Remove all malicious artifacts
- [ ] Verify no backdoors remain (check with Autoruns, process scanning)
- [ ] Patch the exploited vulnerability if one was used

## Phase 4: Recovery
- [ ] Restore from clean backup (verified pre-infection)
- [ ] Validate backup integrity before restoration
- [ ] Rebuild from gold image if backup compromised
- [ ] Verify data integrity after restoration
- [ ] Phased return to production

## Phase 5: Lessons Learned (Within 2 weeks)
- [ ] Full incident timeline documented
- [ ] Root cause identified and remediated
- [ ] Detection gaps addressed
- [ ] CSOC playbook updated
- [ ] Management report delivered

Other supported playbook types:

• Phishing Campaign Response
• Data Breach / Exfiltration
• Business Email Compromise (BEC)
• Insider Threat
• DDoS Attack
• Account Compromise / Credential Stuffing
• Supply Chain Compromise
• Cloud Misconfiguration / Breach

2. Evidence Collection & Chain of Custody

When the user asks to collect forensic evidence:

Order of Volatility (most volatile → least volatile):

1. CPU registers and cache
2. Routing tables, ARP cache, process table
3. Memory (RAM) — ALWAYS capture first
4. Temporary file systems, swap space
5. Running processes and open files
6. Network connections and open ports
7. Disk images
8. Log files (local + remote SIEM)
9. Physical media

Evidence Collection Commands:

# Windows — Live acquisition
winpmem_mini_x64_rc2.exe memory.raw              # Memory dump
tasklist /svc > processes.txt                     # Running processes
netstat -ano > connections.txt                    # Network connections
wmic process get caption,processid,parentprocessid,commandline > process_full.txt
reg export HKLM reg_hklm.reg                     # Registry
dir /s /a "C:\Users\*\AppData\Roaming\*" > appdata.txt

# Linux — Live acquisition
sudo avml /tmp/memory.lime                        # Memory dump (avml)
ps auxf > processes.txt                           # Process tree
netstat -tulnap > connections.txt                 # Network connections
cat /proc/*/cmdline | strings > process_cmdlines.txt
ls -la /tmp/ /var/tmp/ /dev/shm/ > temp_dirs.txt
crontab -l -u root > crontabs.txt
find / -mtime -7 -type f > recently_modified.txt  # Modified in last 7 days

Chain of Custody Template:

## Evidence Chain of Custody Form

| Field | Value |
|-------|-------|
| Evidence ID | IR-2025-001-E01 |
| Incident ID | IR-2025-001 |
| Description | Memory dump from HOSTNAME (192.168.1.100) |
| Collected by | [Analyst Name] |
| Collection time | 2025-05-28 14:30 UTC |
| Collection method | winpmem_mini_x64_rc2.exe |
| MD5 hash | [hash of evidence file] |
| SHA256 hash | [hash of evidence file] |
| Storage location | \nas\ir\IR-2025-001\evidence\ |
| Chain of custody | Analyst → Evidence Locker → Lab |

**Access Log:**
| Date/Time | Person | Purpose | Signature |
|-----------|--------|---------|-----------|
| 2025-05-28 14:30 | [Analyst] | Initial collection | [Sig] |

3. Forensic Timeline Analysis

When the user asks to build an incident timeline:

1. Collect timestamps from all available sources:

• Windows Event Logs (Security, System, Application, PowerShell)
• Web server access logs
• Firewall / proxy logs
• Email server logs (delivery, read receipts)
• File system timestamps (Modified, Accessed, Changed, Born)
• Registry LastWrite timestamps
• Prefetch timestamps (evidence of execution)

1. Normalize to UTC — Confirm system timezone before conversion

1. Generate supertimeline:

``bash python scripts/timeline_builder.py --logs ./collected_logs/ --output timeline.csv python scripts/timeline_builder.py --logs ./logs/ --format html --start "2025-05-20" --end "2025-05-28" ``

1. Identify the kill chain progression:

## Incident Timeline — [Incident ID]

[T-72h] 2025-05-25 09:15 UTC — DELIVERY
  Phishing email received: "Invoice_May2025.pdf.exe" from spoofed sender
  Mail log: SMTP delivery to user@victim.com from 185.x.x.x

[T-48h] 2025-05-26 14:22 UTC — EXECUTION
  User executed attachment: Event 4688 (process creation)
  Parent: outlook.exe → Child: powershell.exe -enc [base64]

[T-48h] 2025-05-26 14:22 UTC — C2 ESTABLISHED
  Outbound connection: 203.x.x.x:443 (beacon_interval: 60s)
  DNS query: malicious-c2.evil.com → 203.x.x.x

[T-24h] 2025-05-27 02:00 UTC — LATERAL MOVEMENT
  PsExec from WORKSTATION01 to SERVER02 (admin$)
  Event 4624 (login type 3) on SERVER02 from WORKSTATION01

[T-2h]  2025-05-27 12:30 UTC — DATA EXFILTRATION
  Large POST request (450MB) to dropbox-like service

[T-0h]  2025-05-28 14:00 UTC — DETECTION
  SOC analyst detected anomalous outbound transfer

4. Memory Forensics

When the user shares Volatility output or asks about memory forensics:

Essential Volatility 3 Commands:

# Process listing
python vol.py -f memory.raw windows.pslist
python vol.py -f memory.raw windows.pstree           # Show parent-child
python vol.py -f memory.raw windows.psscan           # Find hidden processes

# Network connections
python vol.py -f memory.raw windows.netscan
python vol.py -f memory.raw windows.netstat

# DLL and module analysis
python vol.py -f memory.raw windows.dlllist --pid [PID]
python vol.py -f memory.raw windows.modscan          # All loaded modules

# Malware detection
python vol.py -f memory.raw windows.malfind           # Injected code
python vol.py -f memory.raw windows.hollowfind        # Process hollowing

# Registry from memory
python vol.py -f memory.raw windows.registry.hivelist
python vol.py -f memory.raw windows.registry.printkey --key "SOFTWARE\Microsoft\Windows\CurrentVersion\Run"

# File artifacts
python vol.py -f memory.raw windows.filescan
python vol.py -f memory.raw windows.dumpfiles --physaddr [addr]

Suspicious Memory Indicators:

• Process without corresponding disk file (process hollowing)
• explorer.exe or svchost.exe with unusual parent
• Network connections from system processes (lsass.exe, csrss.exe)
• Executable memory regions flagged by windows.malfind
• Stacked THREADS in injected shellcode regions

5. Post-Incident Report

When the user asks for an IR report for management or compliance:

# Post-Incident Report — [Incident ID]

**Classification:** CONFIDENTIAL
**Incident Type:** [Ransomware / Data Breach / etc.]
**Severity:** [Critical / High / Medium]
**Incident Window:** [Start] to [End] UTC
**Systems Affected:** [Count and names]
**Data Impact:** [Data at risk / confirmed exfiltrated]
**Report Date:** [Date]
**Report Author:** [IR Lead]

---

## 1. Executive Summary
[3-4 sentences: what happened, how it happened, impact, and current status]

## 2. Incident Timeline
[Key events table with timestamps]

## 3. Root Cause Analysis
**Initial Vector:** [Phishing / Unpatched service / Credential theft / etc.]
**Root Cause:** [Specific technical cause]
**Contributing Factors:**
- [Factor 1: e.g., no MFA on VPN]
- [Factor 2: e.g., delayed patch deployment]

## 4. Impact Assessment
- **Systems Compromised:** [List]
- **Data Accessed/Exfiltrated:** [Description + quantity]
- **Business Impact:** [Downtime hours, revenue impact, regulatory]
- **Customer/Partner Impact:** [If applicable]

## 5. Containment & Remediation Actions
[Chronological list of actions taken]

## 6. Compliance Notification Requirements
- **GDPR:** [Required if EU personal data — 72-hour notification to DPA]
- **HIPAA:** [Required if PHI — notify HHS within 60 days]
- **PCI-DSS:** [Required if cardholder data — notify card brands immediately]
- **State breach laws:** [Applicable laws and timelines]

## 7. Recommendations
| Priority | Recommendation | Owner | Due Date |
|----------|---------------|-------|---------|
| Critical | Deploy MFA for all remote access | IT | 2025-06-01 |
| High | Accelerate patch cycle for internet-facing systems | IT | 2025-06-15 |
| Medium | Implement email attachment sandboxing | Security | 2025-07-01 |

## 8. Lessons Learned
[What worked, what didn't, process improvements]

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Script Reference

timeline_builder.py

python scripts/timeline_builder.py --logs ./collected_logs/ --output timeline.csv
python scripts/timeline_builder.py --logs ./logs/ --format html --start "2025-05-20" --end "2025-05-28"

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Skill Integration

| Condition | Adjacent Skill | |-----------|---------------| | Alert received from SOC → activate IR | ← Skill 11 (CSOC Automation) | | Malware samples collected → analyze | → Skill 05 (Malware Analysis) | | IOCs extracted → hunt in environment | → Skill 06 (Threat Hunting) | | Log deep-dive needed | → Skill 12 (Log Analysis) |

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References

• NIST SP 800-61 Rev. 2 — Computer Security Incident Handling
• SANS Incident Response Process
• Volatility 3 Documentation
• Velociraptor Documentation
• DFIR.training Resource Hub
• The Art of Memory Forensics (Book)

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v3.0 Enhancements (2026 Update)

Cloud- and identity-era IR:

• Cloud IR — pull and triage AWS CloudTrail, Azure Activity/Entra sign-in & audit, and GCP Audit logs; preserve volatile cloud state (snapshots, IAM key disabling) before remediation.
• Identity & SaaS compromise — handle token theft/replay, OAuth consent abuse, and federated trust attacks; revoke sessions/refresh tokens, rotate signing keys, review conditional-access.
• Modern toolkit — Velociraptor for fleet-scale collection; Hayabusa/Chainsaw + Sigma over EVTX for rapid Windows timelining; KAPE for triage images.
• Ransomware specifics — identify double/triple-extortion, exfil-before-encrypt evidence, ESXi/Linux scope, and recovery validation against immutable backups.
• Business Email Compromise — inbox-rule and forwarding abuse, app-password persistence, mailbox audit log review.

Process rule (unchanged priority): follow NIST SP 800-61 / SANS PICERL; preserve chain of custody; in cloud/OT contexts weigh evidence preservation against service/safety continuity (→ Skill 18 for OT).

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Masriyan
• Source: Masriyan/Claude-Code-CyberSecurity-Skill
• License: MIT
• Homepage: https://www.security-life.org

Install and usage instructions live in the source repository linked above.