AWS Security Audit

Audit AWS security posture via IAM and CloudTrail MCP servers — inspect users, roles, policies, and trace API activity for incident investigation and compliance.

MCP Servers

• IAM MCP: uvx awslabs.iam-mcp-server@latest --readonly (stdio transport)
• CloudTrail MCP: uvx awslabs.cloudtrail-mcp-server@latest (stdio transport)
• Requires: AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_REGION (or AWS_PROFILE)

Key Capabilities

IAM (Identity & Access Management)

• Users: List IAM users, access keys, MFA status, last activity
• Roles: List roles, trust policies, attached permissions
• Policies: Inspect policy documents, identify overly permissive policies
• Groups: List groups and their memberships
• Read-only mode: --readonly flag prevents any IAM modifications

CloudTrail (API Audit Trail)

• Event history: Search recent API calls by user, service, or resource
• Lookup events: Filter by event name, resource type, username
• Time-based queries: Narrow to specific time windows around incidents
• Multi-region: Trail events across all enabled regions

Workflow: Network Security Audit

When a user asks "audit our AWS network security":

1. IAM roles for network services: Check roles used by VPC, TGW, Network Firewall
2. Overly permissive policies: Find policies with ec2:* or *:* actions
3. Unused access keys: Identify stale credentials that should be rotated
4. MFA compliance: Check which users lack MFA
5. CloudTrail check: Recent AuthorizeSecurityGroupIngress, CreateNetworkAcl, ModifyVpcAttribute events
6. Report: Security posture summary with remediation recommendations

Workflow: Incident Investigation

When investigating a security event:

1. CloudTrail lookup: Search events by time window and suspected user/role
2. Identify actions: What API calls were made? DeleteSecurityGroup, ModifySubnetAttribute?
3. Source IP: Where did the API calls originate from?
4. IAM context: What permissions does the user/role have? Should they?
5. Blast radius: What resources were affected?
6. Report: Timeline of events with impact assessment

Workflow: Compliance Check

When checking AWS security compliance:

1. Root account: Check for root access key usage in CloudTrail
2. MFA enforcement: List users without MFA enabled
3. Access key rotation: Find keys older than 90 days
4. Unused credentials: Identify users with no recent activity
5. Policy review: Check for policies granting * on sensitive services
6. Report: Compliance scorecard with findings

Common CloudTrail Network Events

Event Name	What It Means
AuthorizeSecurityGroupIngress	Security group rule added (inbound)
AuthorizeSecurityGroupEgress	Security group rule added (outbound)
RevokeSecurityGroupIngress	Security group rule removed (inbound)
CreateNetworkAclEntry	NACL rule added
CreateRoute	Route table entry added
ModifyVpcAttribute	VPC setting changed
CreateVpnConnection	New VPN tunnel created
AttachInternetGateway	IGW attached to VPC
CreateTransitGatewayRoute	TGW route added
UpdateFirewallRuleGroupRuleList	Network Firewall rule changed

IAM Best Practices for Network Teams

Check	Why It Matters
No ec2:* policies	Prevent accidental network changes
Separate roles per service	Least privilege for VPC, TGW, Firewall
MFA on all humans	Protect against credential theft
No root access keys	Root should use MFA console only
Key rotation < 90 days	Limit exposure of compromised keys
CloudTrail enabled	Audit trail for all API changes

Important Rules

• IAM MCP runs in read-only mode — cannot create, modify, or delete IAM resources
• CloudTrail has event history limits — default 90-day lookback for management events
• Region-specific for CloudTrail — unless using organization trail
• Record in GAIT — log all security investigations for audit trail

Environment Variables

• AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_REGION (or AWS_PROFILE)