Anthropic-Cybersecurity-Skills/skills/performing-service-account-credential-rotation/SKILL.md

name, description, domain, subdomain, tags, version, author, license, nist_csf, mitre_attack, mitre_f3

name	description	domain	subdomain	tags	version	author	license	nist_csf	mitre_attack	mitre_f3
performing-service-account-credential-rotation	Automate credential rotation for service accounts across Active Directory, cloud platforms, and application databases to eliminate stale secrets and reduce compromise risk.	cybersecurity	identity-access-management	service-accounts credential-rotation secrets-management pam automation vault	1.0	mahipal	Apache-2.0	PR.AA-01 PR.AA-02 PR.AA-05 PR.AA-06	T1078 T1110 T1556 T1098 T1003	version tactics techniques 1.1 initial-access positioning stealth id name tactic source F1006.001 Account Takeover: Exposed API Key initial-access f3 id name tactic source F1006.002 Account Takeover: Exposed Login Credential initial-access f3 id name tactic source T1110 Brute Force initial-access attack id name tactic source F1005 Account Manipulation positioning f3 id name tactic source F1023 Device Fingerprint Spoofing stealth f3

Performing Service Account Credential Rotation

Overview

Service accounts are non-human identities used by applications, daemons, CI/CD pipelines, and automated processes to authenticate to systems and APIs. These accounts often have elevated privileges and their credentials (passwords, API keys, certificates, tokens) are frequently long-lived and shared across teams, making them prime targets for attackers. Credential rotation is the systematic process of replacing these secrets on a scheduled basis, propagating new credentials to all dependent systems, and verifying service continuity after rotation.

When to Use

• When conducting security assessments that involve performing service account credential rotation
• When following incident response procedures for related security events
• When performing scheduled security testing or auditing activities
• When validating security controls through hands-on testing

Prerequisites

• Inventory of all service accounts across AD, cloud, and applications
• Secrets management platform (HashiCorp Vault, AWS Secrets Manager, Azure Key Vault, or CyberArk)
• Service dependency mapping (which services use which credentials)
• Change management process for rotation windows
• Monitoring for service health post-rotation

Core Concepts

Service Account Types

Type	Platform	Credential	Rotation Method
Active Directory Service Account	Windows/AD	Password	gMSA (automatic) or PAM-managed
AWS IAM User	AWS	Access Key/Secret Key	AWS Secrets Manager rotation Lambda
GCP Service Account	GCP	JSON key file	Key rotation via IAM API
Azure Service Principal	Azure	Client secret/certificate	Key Vault + rotation policy
Database Service Account	SQL/Oracle/Postgres	Password	Vault dynamic secrets
API Key	SaaS applications	API token	Application-specific API

Group Managed Service Accounts (gMSA)

Windows gMSAs provide automatic password management by Active Directory:

• AD automatically rotates the password every 30 days
• Password is 240 bytes, cryptographically random
• Multiple servers can use the same gMSA simultaneously
• No administrator knows or manages the password
• Eliminates manual rotation for Windows services

Rotation Architecture

Secrets Manager / Vault
        │
        ├── Rotation Trigger (schedule or on-demand)
        │
        ├── Generate new credential
        │
        ├── Update credential at source (AD, cloud IAM, database)
        │
        ├── Update credential in all consumers:
        │   ├── Application configuration
        │   ├── CI/CD pipeline secrets
        │   ├── Kubernetes secrets
        │   └── Other dependent services
        │
        ├── Verify service health
        │   ├── Health check endpoints
        │   ├── Authentication test
        │   └── Functional smoke test
        │
        └── Revoke old credential (after grace period)

Workflow

Step 1: Discover and Inventory Service Accounts

Enumerate all service accounts and their dependencies:

# Active Directory: Find all service accounts
Get-ADServiceAccount -Filter * -Properties *
Get-ADUser -Filter {ServicePrincipalName -ne "$null"} -Properties ServicePrincipalName,PasswordLastSet,LastLogonDate

# Find accounts with passwords older than 90 days
$threshold = (Get-Date).AddDays(-90)
Get-ADUser -Filter {PasswordLastSet -lt $threshold -and Enabled -eq $true} -Properties PasswordLastSet,ServicePrincipalName |
    Where-Object {$_.ServicePrincipalName} |
    Select-Object Name, PasswordLastSet, ServicePrincipalName

Step 2: Implement gMSA for Windows Services

# Create KDS Root Key (one-time, domain-wide)
Add-KdsRootKey -EffectiveImmediately

# Create the gMSA account
New-ADServiceAccount -Name "svc-webapp-gmsa" `
    -DNSHostName "svc-webapp-gmsa.corp.example.com" `
    -PrincipalsAllowedToRetrieveManagedPassword "WebServerGroup" `
    -KerberosEncryptionType AES128,AES256

# Install on target server
Install-ADServiceAccount -Identity "svc-webapp-gmsa"

# Test the account
Test-ADServiceAccount -Identity "svc-webapp-gmsa"

# Configure IIS Application Pool to use gMSA
# Set identity to: CORP\svc-webapp-gmsa$

Step 3: AWS Access Key Rotation with Secrets Manager

import boto3
import json

def rotate_iam_access_key(secret_arn, iam_username):
    """Rotate an IAM user's access key via Secrets Manager."""
    iam = boto3.client("iam")
    sm = boto3.client("secretsmanager")

    # Create new access key
    new_key = iam.create_access_key(UserName=iam_username)
    new_access_key = new_key["AccessKey"]["AccessKeyId"]
    new_secret_key = new_key["AccessKey"]["SecretAccessKey"]

    # Store new credentials in Secrets Manager
    sm.put_secret_value(
        SecretId=secret_arn,
        SecretString=json.dumps({
            "accessKeyId": new_access_key,
            "secretAccessKey": new_secret_key,
            "username": iam_username,
        })
    )

    # List old access keys and deactivate them
    keys = iam.list_access_keys(UserName=iam_username)
    for key in keys["AccessKeyMetadata"]:
        if key["AccessKeyId"] != new_access_key and key["Status"] == "Active":
            iam.update_access_key(
                UserName=iam_username,
                AccessKeyId=key["AccessKeyId"],
                Status="Inactive"
            )

    return {"new_key_id": new_access_key, "old_keys_deactivated": True}

Step 4: Database Credential Rotation with Vault

import hvac

def configure_vault_database_rotation(vault_url, vault_token, db_config):
    """Configure HashiCorp Vault for automatic database credential rotation."""
    client = hvac.Client(url=vault_url, token=vault_token)

    # Enable database secrets engine
    client.sys.enable_secrets_engine(
        backend_type="database",
        path="database"
    )

    # Configure database connection
    client.secrets.database.configure(
        name=db_config["name"],
        plugin_name="postgresql-database-plugin",
        connection_url=f"postgresql://{{{{username}}}}:{{{{password}}}}@"
                       f"{db_config['host']}:{db_config['port']}/{db_config['database']}",
        allowed_roles=[db_config["role_name"]],
        username=db_config["admin_user"],
        password=db_config["admin_password"],
    )

    # Create a role for dynamic credentials
    client.secrets.database.create_role(
        name=db_config["role_name"],
        db_name=db_config["name"],
        creation_statements=[
            "CREATE ROLE \"{{name}}\" WITH LOGIN PASSWORD '{{password}}' VALID UNTIL '{{expiration}}';",
            f"GRANT SELECT, INSERT, UPDATE, DELETE ON ALL TABLES IN SCHEMA public TO \"{{{{name}}}}\";"
        ],
        default_ttl="1h",
        max_ttl="24h",
    )

    return {"status": "configured", "role": db_config["role_name"]}

Step 5: Post-Rotation Verification

After every rotation, verify service continuity:

import requests
import time

def verify_service_health(service_endpoints, max_retries=3, delay=10):
    """Check that services are healthy after credential rotation."""
    results = []
    for endpoint in service_endpoints:
        for attempt in range(max_retries):
            try:
                response = requests.get(
                    endpoint["health_url"],
                    timeout=10,
                    headers=endpoint.get("headers", {})
                )
                healthy = response.status_code == 200
                results.append({
                    "service": endpoint["name"],
                    "status": "healthy" if healthy else f"unhealthy ({response.status_code})",
                    "attempt": attempt + 1,
                })
                if healthy:
                    break
            except requests.RequestException as e:
                results.append({
                    "service": endpoint["name"],
                    "status": f"error: {str(e)}",
                    "attempt": attempt + 1,
                })
            if attempt < max_retries - 1:
                time.sleep(delay)

    return results

Validation Checklist

• Complete inventory of service accounts with dependency mapping
• gMSA implemented for all eligible Windows service accounts
• Cloud access keys rotated via secrets manager (AWS, GCP, Azure)
• Database credentials managed via dynamic secrets (Vault) or rotation policy
• Rotation schedule defined (30-90 days depending on risk level)
• Post-rotation health checks automated
• Alerting configured for rotation failures
• Old credentials revoked after grace period
• Rotation events logged and auditable
• Rollback procedure documented and tested

References

• Google Cloud Service Account Key Rotation
• AWS Secrets Manager Rotation
• Microsoft gMSA Documentation
• HashiCorp Vault Database Secrets Engine