building-soc-playbook-for-ransomware

Building SOC Playbook for Ransomware

When to Use

Use this skill when:

• SOC teams need a standardized ransomware response playbook for Tier 1-3 analysts
• An organization lacks documented procedures for ransomware containment and recovery
• Tabletop exercises reveal gaps in ransomware response coordination
• Compliance requirements (NIST CSF, ISO 27001) mandate documented incident playbooks

Do not use during an active ransomware incident as the sole guide — have pre-built playbooks tested and rehearsed before incidents occur.

Prerequisites

• SIEM platform (Splunk ES, Elastic Security, or Sentinel) with endpoint and network data
• EDR solution (CrowdStrike, SentinelOne, or Microsoft Defender for Endpoint) with network isolation capability
• Backup infrastructure with tested recovery procedures and offline/immutable backups
• Communication plan with legal, executive leadership, and external IR retainer contacts
• MITRE ATT&CK knowledge for ransomware technique chains

Workflow

Step 1: Define Detection Triggers

Create SIEM detection rules for early ransomware indicators:

Mass File Encryption Detection (Splunk):

index=sysmon EventCode=11
| bin _time span=1m
| stats dc(TargetFilename) AS unique_files, values(TargetFilename) AS sample_files by Computer, Image, _time
| where unique_files > 100
| eval suspicious_extensions = if(match(mvjoin(sample_files, ","), "\.(encrypted|locked|crypt|enc|ransom)"), "YES", "NO")
| where suspicious_extensions="YES" OR unique_files > 500
| sort - unique_files

Shadow Copy Deletion (T1490):

index=wineventlog sourcetype="WinEventLog:Security" OR index=sysmon EventCode=1
(CommandLine="*vssadmin*delete*shadows*" OR CommandLine="*wmic*shadowcopy*delete*"
 OR CommandLine="*bcdedit*/set*recoveryenabled*no*" OR CommandLine="*wbadmin*delete*catalog*")
| table _time, Computer, User, ParentImage, Image, CommandLine

Ransomware Note File Creation:

index=sysmon EventCode=11
TargetFilename IN ("*README*.txt", "*DECRYPT*.txt", "*RANSOM*.txt", "*RECOVER*.html", "*HOW_TO*.txt")
| stats count by Computer, Image, TargetFilename
| where count > 5