From cybersecurity-skills
Guides incident response in AWS, Azure, GCP: analyzes CloudTrail/Activity/Audit logs, contains identity compromises, isolates resources, acquires forensics for ephemeral infra.
npx claudepluginhub mukul975/anthropic-cybersecurity-skills --plugin cybersecurity-skillsThis skill uses the workspace's default tool permissions.
- Cloud security posture management (CSPM) alerts on unauthorized resource changes
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Do not use for on-premises-only incidents with no cloud component; use standard enterprise IR procedures.
Identify the scope and nature of the compromise:
AWS Indicators:
CloudTrail suspicious events to investigate:
- ConsoleLogin from unexpected geolocation or IP
- CreateAccessKey for existing IAM user (persistence)
- RunInstances for crypto-mining (large instance types)
- PutBucketPolicy making S3 bucket public
- AssumeRole to cross-account roles
- DeleteTrail or StopLogging (defense evasion)
- CreateUser or AttachUserPolicy (privilege escalation)
Azure Indicators:
Azure Activity Log events to investigate:
- Sign-in from anonymous IP or TOR exit node
- Service principal credential added
- Role assignment changes (Owner, Contributor added)
- VM created in unusual region
- Storage account access key regenerated
- Conditional Access policy modified or deleted
- MFA disabled for user account
GCP Indicators:
GCP Audit Log events to investigate:
- SetIamPolicy changes granting broad access
- CreateServiceAccountKey for existing SA
- InsertInstance in unexpected zone
- SetBucketIamPolicy with allUsers
- DeleteLog or UpdateSink (log tampering)
Cloud containment is primarily an identity operation:
AWS Containment:
# Disable compromised IAM access keys
aws iam update-access-key --user-name compromised-user \
--access-key-id AKIA... --status Inactive
# Attach deny-all policy to compromised user
aws iam attach-user-policy --user-name compromised-user \
--policy-arn arn:aws:iam::aws:policy/AWSDenyAll
# Revoke all active sessions for compromised IAM role
aws iam put-role-policy --role-name compromised-role \
--policy-name RevokeOlderSessions --policy-document '{
"Version":"2012-10-17",
"Statement":[{
"Effect":"Deny",
"Action":"*",
"Resource":"*",
"Condition":{"DateLessThan":
{"aws:TokenIssueTime":"2025-11-15T15:00:00Z"}}
}]
}'
# Isolate compromised EC2 instance
aws ec2 modify-instance-attribute --instance-id i-0abc123 \
--groups sg-isolate-forensic
Azure Containment:
# Disable compromised user
Set-AzureADUser -ObjectId "user@tenant.onmicrosoft.com" -AccountEnabled $false
# Revoke all sessions
Revoke-AzureADUserAllRefreshToken -ObjectId "user-object-id"
# Remove role assignments
Remove-AzRoleAssignment -ObjectId "sp-object-id" -RoleDefinitionName "Contributor"
# Isolate VM with NSG deny-all rule
$nsg = New-AzNetworkSecurityGroup -Name "isolate-nsg" -ResourceGroupName "rg" -Location "eastus"
$nsg | Add-AzNetworkSecurityRuleConfig -Name "DenyAll" -Priority 100 -Direction Inbound `
-Access Deny -Protocol * -SourceAddressPrefix * -SourcePortRange * `
-DestinationAddressPrefix * -DestinationPortRange *
Collect evidence before ephemeral resources are terminated or logs rotate:
AWS Evidence Collection:
Azure Evidence Collection:
GCP Evidence Collection:
Analyze logs for common cloud attack techniques:
Common Cloud Attack Patterns:
━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1. Credential Compromise → IAM Privilege Escalation → Resource Abuse
2. Public S3/Blob → Data Exfiltration
3. SSRF from Web App → IMDS Token Theft → Lateral Movement
4. Compromised CI/CD Pipeline → Malicious Deployment
5. Cross-Account Role Abuse → Multi-Account Pivot
6. Lambda/Function Abuse → Crypto-mining or Data Processing
IMDS Token Theft Investigation (AWS):
# Search CloudTrail for API calls using instance role credentials from external IP
aws cloudtrail lookup-events --lookup-attributes \
AttributeKey=EventSource,AttributeValue=ec2.amazonaws.com \
--start-time 2025-11-14 --end-time 2025-11-16 \
| jq '.Events[] | select(.CloudTrailEvent | fromjson | .sourceIPAddress != "internal")'
Remove adversary access and restore secure state:
Implement controls to prevent recurrence:
| Term | Definition |
|---|---|
| IMDS (Instance Metadata Service) | Cloud service providing instance credentials accessible from within a VM; SSRF attacks target IMDS to steal tokens |
| CloudTrail | AWS service logging all API calls across the AWS account; primary evidence source for AWS incident response |
| Service Principal | Non-human identity in Azure AD used by applications and services; compromise enables persistent API access |
| SCP (Service Control Policy) | AWS Organizations policy that limits the maximum permissions available to accounts; useful for guardrails |
| Ephemeral Infrastructure | Cloud resources (containers, functions, auto-scaled instances) that may be terminated before evidence can be collected |
| Cross-Account Role Assumption | AWS mechanism allowing one account to temporarily access resources in another; attackers pivot through assumed roles |
Context: AWS GuardDuty alerts on API calls from an unexpected IP address using an IAM user's access key. The key was accidentally committed to a public GitHub repository 4 hours ago.
Approach:
Pitfalls:
CLOUD INCIDENT RESPONSE REPORT
================================
Incident: INC-2025-1705
Cloud Provider: AWS (Account: 123456789012)
Date Detected: 2025-11-15T14:00:00Z
Detection Source: GuardDuty - UnauthorizedAccess:IAMUser/InstanceCredentialExfiltration
COMPROMISE SUMMARY
Initial Access: IAM access key exposed in public GitHub repo
Affected Identity: iam-user: deploy-bot (AKIA...)
Attacker IP: 203.0.113.42 (VPN exit node, Netherlands)
Duration: 4 hours (10:00 UTC - 14:00 UTC)
ATTACKER ACTIVITY (from CloudTrail)
10:15 UTC - DescribeInstances (reconnaissance)
10:18 UTC - RunInstances x 12 (c5.4xlarge, all regions - crypto-mining)
10:22 UTC - CreateUser "backup-admin" (persistence)
10:23 UTC - CreateAccessKey for "backup-admin"
10:25 UTC - AttachUserPolicy - AdministratorAccess to "backup-admin"
10:30 UTC - PutBucketPolicy - s3://data-bucket made public (exfiltration)
CONTAINMENT ACTIONS
[x] Original access key disabled
[x] User policy set to AWSDenyAll
[x] Backdoor IAM user "backup-admin" deleted
[x] 12 crypto-mining instances terminated (all regions)
[x] S3 bucket policy restored to private
FINANCIAL IMPACT
Unauthorized EC2: $2,847 (4 hours x 12 x c5.4xlarge)
Data Transfer: $127 (S3 public access data egress)
Total: $2,974
POST-INCIDENT HARDENING
1. GitHub secret scanning enabled
2. Access key rotation policy implemented
3. SCP preventing CloudTrail disablement deployed
4. GuardDuty auto-remediation Lambda configured