File Waster Incident Response Checklist for IT AdministratorsFile Waster is a hypothetical or real threat name that suggests malware or a destructive tool designed to corrupt, delete, or otherwise render files unusable. Whether File Waster is a new ransomware, a wiper, or an aggressive file-corruption tool, IT administrators must be prepared with a clear, actionable incident response checklist. This article provides a comprehensive, step-by-step guide for detection, containment, eradication, recovery, and post-incident activities tailored to an organization facing a File Waster incident.
Executive summary
File Waster incidents can quickly escalate from isolated workstation damage to enterprise-wide data loss. Rapid, well-coordinated response reduces downtime, limits data loss, preserves evidence for forensic analysis, and protects organizational reputation. This checklist assumes your organization has at least a basic incident response (IR) plan and escalation paths; it fills in specific actions and considerations for a destructive file-focused incident.
Preparation (before an incident)
Policies, roles, and communication
- Maintain an up-to-date incident response plan that defines roles (Incident Response Lead, Forensics, Legal, Communications, IT Operations, HR).
- Pre-authorize emergency decisions and access for IR team members (e.g., network segmentation, access to backups).
- Maintain contact lists: internal stakeholders, external vendors (forensics, legal counsel), and law enforcement points of contact.
- Prepare templated internal and external communications to reduce time when an incident occurs.
Backups and recovery readiness
- Ensure regular, tested backups with offline and immutable copies. Backups should be air-gapped or stored with write-once protections to prevent tampering.
- Document Recovery Time Objectives (RTOs) and Recovery Point Objectives (RPOs) for critical systems.
- Periodically test full restorations — not just backup completion — with tabletop exercises and real restore drills.
Detection and monitoring
- Deploy endpoint detection and response (EDR) with file integrity monitoring and behavioral analytics to detect mass deletions or unusual file activity.
- Configure SIEM to alert on rapid file modifications, deletion spikes, suspicious processes modifying many files, and unexpected account privilege escalations.
- Maintain detailed logs (file access, authentication, process execution, network flows) and ensure log retention is sufficient for forensic timelines.
Environment hardening
- Enforce least privilege and multi-factor authentication (MFA) for all administrative and remote access.
- Segment networks to limit lateral movement; apply strong ACLs and micro-segmentation where possible.
- Harden services that expose file shares (SMB), disable legacy protocols, and apply up-to-date patches.
Detection: Signs of File Waster activity
Common indicators that point to a destructive file-based incident:
- Sudden mass file deletion or bulk file corruption across multiple endpoints or file servers.
- Rapid creation of temporary or random-named files followed by original file disappearance or corruption.
- Unusual process names or known malicious binaries executing with file-system write patterns.
- Increased CPU/disk I/O across many machines simultaneously during unexpected hours.
- Ransom notes, changed file extensions, or clear textual markers left by malware.
- Elevated alerts from EDR or SIEM for file integrity or multiple hosts exhibiting the same anomalous behavior.
If one or more indicators are present, escalate to containment immediately.
Containment checklist (first 0–4 hours)
- Activate the incident response team and log all actions (who, what, when).
- Isolate affected hosts from the network (remove network access or place in a quarantine VLAN). Avoid powering off machines unless directed by forensics — volatile memory may contain important evidence.
- Disable shared file services or apply temporary ACLs to prevent further spread to file servers and NAS devices.
- Block known malicious command-and-control IPs/domains at perimeter devices and update IDS/IPS rules to detect propagation patterns.
- Revoke or reset credentials for accounts that appear compromised, starting with service and admin accounts. Enforce MFA if not already in place.
- Collect preliminary volatile evidence (memory images, running process lists, network connections) from representative affected systems for forensic analysis. Use standardized acquisition tools and document chain-of-custody.
- Preserve logs and snapshot affected storage systems; make read-only copies of critical file servers for analysis.
- If ransomware-like behavior is suspected, do not pay ransom without legal counsel and risk assessment. Preserve all evidence for law enforcement.
Eradication and investigation (4–72 hours)
- Work with forensic analysts to determine the initial access vector (phishing, vulnerable exposed service, compromised credentials, supply-chain).
- Identify IOCs (file hashes, mutexes, registry keys, domains, IPs, filenames) and push to EDR/SIEM for hunting.
- Remove malicious artifacts: delete or disable backdoor accounts, remove malicious scheduled tasks, kill persistence mechanisms. Patch exploited vulnerabilities and rotate credentials for affected systems.
- Scan the environment for lateral movement traces and additional compromised hosts. Use EDR telemetry and network flow logs to find communication chains.
- If backups were impacted, validate which backup sets are clean. For compromised backups, attempt to find historical backups or offsite copies that predate the incident.
- Reimage compromised hosts if integrity cannot be assured; avoid restoring from possibly infected snapshots.
Recovery checklist (72+ hours)
- Prioritize systems for recovery according to business impact (finance, customer-facing services, core operations).
- Restore systems from validated clean backups. Before reconnecting to production networks, verify integrity and patch levels.
- Rebuild identity infrastructure and rotate all relevant credentials. Confirm MFA enforcement for critical accounts.
- Apply network segmentation and hardening measures that were identified as weaknesses.
- Monitor restored systems closely with heightened logging and EDR signatures for re-infection signs.
- Return systems to production in staged waves with validation checks at each stage.
Communication and legal considerations
- Notify legal counsel and follow regulatory obligations for breach notifications (timing and required content vary by jurisdiction and industry).
- Prepare clear internal communications for employees with guidance on device usage, password resets, and phishing awareness.
- External communications (customers, partners, regulators) should be coordinated with legal and PR; provide factual, concise updates without speculation.
- Engage law enforcement and cybersecurity authorities where appropriate; preserve evidence chain-of-custody for potential criminal investigation.
Post-incident activities and lessons learned
- Conduct a formal post-incident review (PIR) within 1–2 weeks including stakeholders across IT, security, legal, and business units. Document timeline, root cause, impact, and decisions made.
- Update IR playbooks with lessons learned — e.g., gaps in logging, backup deficiencies, or slow decision points.
- Implement remediation from root-cause analysis: patching, configuration changes, network segmentation, access control changes, and improved monitoring.
- Run phishing exercises and security awareness training addressing the exploited vector.
- Validate and, if necessary, revise backup and recovery strategies; increase frequency of restore drills.
- Maintain longer-term monitoring for dormant threats or re-compromise attempts.
Technical checklist (quick reference)
- Isolate affected hosts — yes/no
- Collect volatile evidence — yes/no
- Preserve and snapshot file servers — yes/no
- Identify clean backup set(s) — yes/no
- Reimage or rebuild compromised hosts — yes/no
- Rotate credentials and enforce MFA — yes/no
- Apply patches and close exploited vectors — yes/no
- Notify legal and law enforcement — yes/no
- Conduct post-incident review and remediation — yes/no
Example playbook snippet (sample steps an IR analyst might follow)
- Triage: Confirm multiple endpoints report mass file deletion events within the last hour.
- Contain: Quarantine affected endpoints, disable SMB shares, and block outbound connections to suspicious domains.
- Preserve: Take memory images from 3 representative systems and copy logs from file servers to secure storage.
- Hunt: Use EDR to run queries for the process name and hash observed; expand to all endpoints.
- Restore: Validate last known clean backups (date/time) and restore a test server. If clean, schedule staged restoration.
- Clean-up: Reimage infected hosts, rotate service credentials, and apply missing patches.
Common pitfalls and how to avoid them
- Relying solely on backups that were online and accessible to attackers — maintain air-gapped or immutable backups.
- Delayed activation of the IR team — use clear escalation criteria and automated alerts.
- Poor logging or insufficient retention — ensure logs are centralized and retained for forensic timelines.
- Over-sharing public details — coordinate messaging to avoid legal/regulatory complications.
- Not testing restorations — drill restores regularly to ensure recovery actually works.
Final notes
Dealing with a File Waster incident requires speed, coordination, and discipline. The steps above form a comprehensive checklist that helps minimize damage, restore services, and improve defenses. Keeping backups safe, maintaining up-to-date detection capabilities, and practicing the incident response playbook are the best defenses against destructive file-based attacks.