incident-response

Security Incident Response

Overview

This skill covers security incident handling in ServiceNow:

• Detecting potential security incidents
• Classifying security threats
• Containment procedures
• Investigation and evidence gathering
• Communication protocols
• Post-incident review

When to use: Upon detection of any potential security threat, unauthorized access, data breach, or suspicious activity.

Prerequisites

• Roles: sn_si.admin (Security Incident Response), security_admin
• Access: Security Incident tables, audit logs, system logs
• Plugins: Security Incident Response (sn_si)

Procedure

Phase 1: Detection & Identification

Common Detection Sources:

• User reports (phishing, suspicious email)
• SIEM alerts
• Audit log anomalies
• Failed login spikes
• Unusual data access patterns

Query for Suspicious Login Activity:

Tool: SN-Query-Table
Parameters:
  table_name: sys_audit
  query: tablename=sys_user^fieldname=failed_attempts^newvalueGT5^sys_created_onONLast 24 hours
  fields: documentkey,user,newvalue,sys_created_on
  limit: 100

Check Recent Admin Actions:

Tool: SN-Query-Table
Parameters:
  table_name: sys_audit
  query: sys_created_onONLast hour^userLIKEadmin
  fields: tablename,fieldname,oldvalue,newvalue,user,sys_created_on
  limit: 50

Phase 2: Classification

Security Incident Severity Matrix:

Severity	Impact	Examples
Critical	Business-wide	Ransomware, data breach, admin compromise
High	Department-wide	Unauthorized access to sensitive data
Medium	Limited scope	Phishing attempt, malware on single system
Low	Minimal	Spam, failed attack attempts

Create Security Incident:

Tool: SN-Create-Record
Parameters:
  table_name: sn_si_incident
  data:
    short_description: "Potential unauthorized access - Admin account"
    description: |
      Detection: Multiple failed login attempts followed by successful login
      Source IP: 203.0.113.50 (external)
      Target Account: admin.user@company.com
      Time: 2026-02-06 14:30 UTC

      Initial Analysis:
      - 15 failed attempts over 5 minutes
      - Successful login from unfamiliar IP
      - Unusual time (outside business hours)
    category: Unauthorized Access
    subcategory: Account Compromise
    priority: 1
    state: Analysis
    affected_user: [user_sys_id]
    business_criticality: Critical

Phase 3: Containment

Immediate Actions (Critical/High):

1. Disable Compromised Account:

Tool: SN-Update-Record
Parameters:
  table_name: sys_user
  sys_id: [compromised_user_sys_id]
  data:
    locked_out: true
    active: false

1. Revoke Active Sessions:

Tool: SN-Execute-Background-Script
Parameters:
  script: |
    var gr = new GlideRecord('v_user_session');
    gr.addQuery('user', '[compromised_user_sys_id]');
    gr.query();
    while (gr.next()) {
      gr.deleteRecord();
    }
    gs.info('Terminated all sessions for compromised user');
  description: "Emergency: Terminate compromised user sessions"

1. Document Containment Action:

Tool: SN-Add-Work-Notes
Parameters:
  sys_id: [security_incident_sys_id]
  table_name: sn_si_incident
  work_notes: |
    CONTAINMENT ACTION - [TIMESTAMP]

    Actions Taken:
    1. Account locked - sys_user.locked_out = true
    2. Account deactivated - sys_user.active = false
    3. Active sessions terminated - v_user_session cleared

    Performed by: [Analyst Name]
    Approved by: [Manager Name]

Phase 4: Investigation

Gather Evidence:

1. Audit Trail for Affected User:

Tool: SN-Query-Table
Parameters:
  table_name: sys_audit
  query: user=[compromised_user_id]^sys_created_onONLast 7 days
  fields: tablename,fieldname,oldvalue,newvalue,sys_created_on
  limit: 500

1. System Logs:

Tool: SN-Query-Table
Parameters:
  table_name: syslog
  query: sys_created_onONLast 24 hours^messageLIKElogin
  fields: level,message,source,sys_created_on
  limit: 200

1. Data Access Logs:

Tool: SN-Query-Table
Parameters:
  table_name: sys_audit
  query: user=[user_id]^tablenameINsys_user,customer_account,hr_core_profile
  fields: tablename,documentkey,fieldname,sys_created_on

Document Findings:

Tool: SN-Add-Work-Notes
Parameters:
  sys_id: [security_incident_sys_id]
  work_notes: |
    INVESTIGATION FINDINGS - [TIMESTAMP]

    Timeline:
    - 14:25 - First failed login attempt
    - 14:30 - Successful login from IP 203.0.113.50
    - 14:32 - Accessed HR records
    - 14:35 - Downloaded employee list
    - 14:40 - Session terminated by security

    Data Accessed:
    - hr_core_profile: 150 records viewed
    - sys_user: 50 records exported

    Indicators of Compromise:
    - External IP (not company VPN)
    - Outside business hours
    - Bulk data access pattern

Phase 5: Eradication & Recovery

Reset Credentials:

Tool: SN-Execute-Background-Script
Parameters:
  script: |
    var user = new GlideRecord('sys_user');
    user.get('[compromised_user_sys_id]');
    user.user_password.setDisplayValue('TEMP-' + gs.generateGUID().substring(0,8));
    user.update();
    gs.info('Password reset for: ' + user.user_name);
  description: "Reset compromised user password"

Reactivate with Enhanced Security:

Tool: SN-Update-Record
Parameters:
  table_name: sys_user
  sys_id: [user_sys_id]
  data:
    active: true
    locked_out: false
    password_needs_reset: true
    failed_attempts: 0

Phase 6: Communication

Notification Templates:

To Affected User:

Subject: Security Action Required - Account Access

Your account was temporarily disabled due to suspicious activity. Your password has been reset. Please contact IT Security at x1234 to verify your identity and receive new credentials.

To Management:

Security Incident #[number] - Status Update

Summary: [Brief description] Impact: [Scope of impact] Current Status: [Contained/Investigating/Resolved] Actions Taken: [List of actions] Next Steps: [Planned actions]

Phase 7: Post-Incident Review

Close Security Incident:

Tool: SN-Update-Record
Parameters:
  table_name: sn_si_incident
  sys_id: [incident_sys_id]
  data:
    state: Closed
    close_code: Resolved
    close_notes: |
      Resolution Summary:
      - Compromised credentials reset
      - No data exfiltration confirmed
      - User re-trained on security awareness

      Root Cause: Weak password + phishing attack

      Preventive Actions:
      - MFA enabled for all admin accounts
      - Password policy strengthened
      - Phishing training scheduled

      Lessons Learned documented in KB0012345

Response Time Targets

Severity	Initial Response	Containment	Resolution
Critical	15 minutes	1 hour	24 hours
High	1 hour	4 hours	72 hours
Medium	4 hours	24 hours	1 week
Low	24 hours	1 week	2 weeks

Best Practices

• Preserve Evidence: Don't modify or delete logs before investigation
• Document Everything: Every action should be recorded in work notes
• Follow Chain of Custody: Track who accessed what evidence
• Need-to-Know: Limit incident details to essential personnel
• Legal Considerations: Engage legal for data breaches

Troubleshooting

Cannot Access Security Incident Tables

Cause: Missing Security Incident Response plugin or roles Solution: Verify sn_si plugin is active; request sn_si.admin role

Audit Logs Missing

Cause: Auditing not enabled for table Solution: Check sys_dictionary for audit flag on table

Related Skills

• security/audit-compliance - Compliance checking
• itsm/major-incident - Major incident handling
• security/acl-management - Access control

References

• NIST Incident Response Guide
• ServiceNow Security Incident Response
• SANS Incident Handler's Handbook