Anthropic-Cybersecurity-Skills/skills/performing-cloud-incident-containment-procedures/references/api-reference.md

API Reference: AWS Cloud Incident Containment

Libraries Used

Library	Purpose
boto3	AWS SDK for EC2, IAM, Security Groups, and CloudTrail
json	Parse and log containment actions
datetime	Timestamp containment events

Installation

pip install boto3

Authentication

import boto3
import os

session = boto3.Session(
    aws_access_key_id=os.environ.get("AWS_ACCESS_KEY_ID"),
    aws_secret_access_key=os.environ.get("AWS_SECRET_ACCESS_KEY"),
    region_name=os.environ.get("AWS_REGION", "us-east-1"),
)

ec2 = session.client("ec2")
iam = session.client("iam")

Containment Actions

Isolate EC2 Instance (Security Group Quarantine)

def isolate_instance(instance_id):
    """Replace instance security groups with a quarantine SG that blocks all traffic."""
    # Create quarantine SG if it doesn't exist
    vpc_id = ec2.describe_instances(
        InstanceIds=[instance_id]
    )["Reservations"][0]["Instances"][0]["VpcId"]

    try:
        quarantine_sg = ec2.create_security_group(
            GroupName="quarantine-no-access",
            Description="IR Quarantine — blocks all inbound/outbound",
            VpcId=vpc_id,
        )
        sg_id = quarantine_sg["GroupId"]
        # Revoke default outbound rule
        ec2.revoke_security_group_egress(
            GroupId=sg_id,
            IpPermissions=[{"IpProtocol": "-1", "IpRanges": [{"CidrIp": "0.0.0.0/0"}]}],
        )
    except ec2.exceptions.ClientError:
        # SG already exists
        sgs = ec2.describe_security_groups(
            Filters=[{"Name": "group-name", "Values": ["quarantine-no-access"]}]
        )
        sg_id = sgs["SecurityGroups"][0]["GroupId"]

    # Apply quarantine SG (replaces all existing SGs)
    ec2.modify_instance_attribute(
        InstanceId=instance_id,
        Groups=[sg_id],
    )
    return {"instance_id": instance_id, "quarantine_sg": sg_id, "action": "isolated"}

Disable IAM Access Keys

def disable_user_access_keys(username):
    """Disable all access keys for a compromised IAM user."""
    keys = iam.list_access_keys(UserName=username)
    disabled = []
    for key in keys["AccessKeyMetadata"]:
        if key["Status"] == "Active":
            iam.update_access_key(
                UserName=username,
                AccessKeyId=key["AccessKeyId"],
                Status="Inactive",
            )
            disabled.append(key["AccessKeyId"])
    return {"username": username, "keys_disabled": disabled}

Revoke IAM Role Sessions

def revoke_role_sessions(role_name):
    """Revoke all active sessions for an IAM role."""
    iam.put_role_policy(
        RoleName=role_name,
        PolicyName="RevokeOlderSessions",
        PolicyDocument=json.dumps({
            "Version": "2012-10-17",
            "Statement": [{
                "Effect": "Deny",
                "Action": "*",
                "Resource": "*",
                "Condition": {
                    "DateLessThan": {
                        "aws:TokenIssueTime": datetime.utcnow().strftime("%Y-%m-%dT%H:%M:%SZ")
                    }
                }
            }]
        }),
    )
    return {"role": role_name, "action": "sessions_revoked"}

Snapshot EBS Volume for Forensics

def snapshot_instance_volumes(instance_id):
    """Create forensic snapshots of all attached EBS volumes."""
    instance = ec2.describe_instances(InstanceIds=[instance_id])
    volumes = instance["Reservations"][0]["Instances"][0].get("BlockDeviceMappings", [])
    snapshots = []
    for vol in volumes:
        vol_id = vol["Ebs"]["VolumeId"]
        snap = ec2.create_snapshot(
            VolumeId=vol_id,
            Description=f"IR forensic snapshot — {instance_id} — {vol_id}",
            TagSpecifications=[{
                "ResourceType": "snapshot",
                "Tags": [
                    {"Key": "Purpose", "Value": "incident-response"},
                    {"Key": "SourceInstance", "Value": instance_id},
                ]
            }],
        )
        snapshots.append({"volume_id": vol_id, "snapshot_id": snap["SnapshotId"]})
    return snapshots

Stop Instance (Preserve State)

def stop_instance(instance_id):
    """Stop instance without terminating to preserve memory and disk."""
    ec2.stop_instances(InstanceIds=[instance_id])
    return {"instance_id": instance_id, "action": "stopped"}

Block Public S3 Bucket Access

s3 = session.client("s3")

def block_public_bucket(bucket_name):
    s3.put_public_access_block(
        Bucket=bucket_name,
        PublicAccessBlockConfiguration={
            "BlockPublicAcls": True,
            "IgnorePublicAcls": True,
            "BlockPublicPolicy": True,
            "RestrictPublicBuckets": True,
        },
    )
    return {"bucket": bucket_name, "action": "public_access_blocked"}

Output Format

{
  "incident_id": "IR-2025-001",
  "containment_time": "2025-01-15T10:30:00Z",
  "actions_taken": [
    {"action": "isolate_instance", "target": "i-0abc123", "status": "success"},
    {"action": "disable_access_keys", "target": "compromised-user", "keys_disabled": 2},
    {"action": "snapshot_volumes", "target": "i-0abc123", "snapshots": 2},
    {"action": "stop_instance", "target": "i-0abc123", "status": "success"}
  ]
}