Building Soc Playbook For Ransomware

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

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

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

sequence by host.name with maxspan=2m
  [process where event.type == "start" and
    process.args : ("*vssadmin*", "*delete*", "*shadows*")]
  [file where event.type == "creation" and
    file.name : ("*README*DECRYPT*", "*RANSOM*", "*HOW_TO_RECOVER*")]

RANSOMWARE ALERT TRIAGE
│
├── Is encryption actively occurring?
│   ├── YES → IMMEDIATE: Isolate host from network (Step 3)
│   │         Do NOT power off (preserve memory for forensics)
│   └── NO → Is this a pre-encryption indicator?
│       ├── Shadow copy deletion → HIGH PRIORITY: Isolate and investigate
│       ├── Known ransomware hash → HIGH PRIORITY: Block hash, scan enterprise
│       └── Suspicious process behavior → MEDIUM: Investigate, prepare isolation
│
├── How many hosts affected?
│   ├── Single host → Contained incident, follow host isolation procedure
│   ├── Multiple hosts (2-10) → Escalate to Tier 2, begin enterprise-wide scan
│   └── Enterprise-wide (>10) → Activate full IR team, engage external retainer
│
└── Is data exfiltration confirmed?
    ├── YES → Double extortion scenario, engage legal for breach notification
    └── NO/UNKNOWN → Check for Cobalt Strike/C2 beacons, review outbound transfers

# Isolate host using CrowdStrike Falcon API
curl -X POST "https://api.crowdstrike.com/devices/entities/devices-actions/v2?action_name=contain" \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"ids": ["device_id_here"]}'

# Isolate machine via MDE API
$headers = @{Authorization = "Bearer $token"}
$body = @{Comment = "Ransomware containment - IR-2024-0500"; IsolationType = "Full"} | ConvertTo-Json
Invoke-RestMethod -Uri "https://api.securitycenter.microsoft.com/api/machines/$machineId/isolate" `
    -Method Post -Headers $headers -Body $body -ContentType "application/json"

# Palo Alto — Block SMB lateral spread
set rulebase security rules RansomwareContainment from Trust to Trust
set rulebase security rules RansomwareContainment application ms-ds-smb
set rulebase security rules RansomwareContainment action deny
set rulebase security rules RansomwareContainment disabled no
commit

# Disable compromised account
Disable-ADAccount -Identity "compromised_user"

# Reset Kerberos TGT (if domain admin compromised)
# WARNING: This resets krbtgt and requires two resets 12+ hours apart
Reset-KrbtgtKeys -Server "DC-PRIMARY" -Force

# Block lateral movement by disabling remote services
Set-Service -Name "RemoteRegistry" -StartupType Disabled -Status Stopped

# Capture running processes and network connections
Get-Process | Export-Csv "C:\IR\processes_$(hostname).csv"
Get-NetTCPConnection | Export-Csv "C:\IR\netstat_$(hostname).csv"

# Capture memory dump (if host still running)
winpmem_mini_x64.exe C:\IR\memory_$(hostname).raw

# Collect ransomware artifacts
Copy-Item "C:\Users\*\Desktop\*README*" "C:\IR\ransom_notes\" -Recurse
Copy-Item "C:\Users\*\Desktop\*.encrypted" "C:\IR\encrypted_samples\" -Force

# Capture event logs
wevtutil epl Security "C:\IR\Security_$(hostname).evtx"
wevtutil epl System "C:\IR\System_$(hostname).evtx"
wevtutil epl "Microsoft-Windows-Sysmon/Operational" "C:\IR\Sysmon_$(hostname).evtx"

index=sysmon (EventCode=1 OR EventCode=11 OR EventCode=3)
(TargetFilename="*ransomware_binary_name*" OR sha256="KNOWN_HASH"
 OR DestinationIp="C2_IP_ADDRESS" OR CommandLine="*malicious_command*")
| stats count by Computer, EventCode, Image, CommandLine
| sort - count

POST-INCIDENT REVIEW TEMPLATE
1. Timeline of events (detection to full recovery)
2. Initial access vector identification
3. Dwell time analysis (time from initial compromise to encryption)
4. Detection gaps identified
5. Response effectiveness metrics (MTTD, MTTC, MTTR)
6. Playbook improvements recommended
7. New detection rules deployed
8. Backup and recovery procedure updates