网络安全最佳实践
使用安全组、网络 ACL 和私有端点，为 VPC 中的 Lambda 函数实施可靠的网络安全措施，尽量缩小攻击面
网络安全最佳实践 是 CoddyKit 上的免费 Serverless AWS Lambda Development 课时。 这是第 3 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 Serverless AWS Lambda Development 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Serverless AWS Lambda Development 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
Secure Lambda in a VPC
When your AWS Lambda function operates within a Virtual Private Cloud (VPC), it gains access to private resources like databases. This also means you need to secure its network communication.
Network security is critical to prevent unauthorized access and data breaches for your serverless applications.
Security Groups Explained
Security Groups (SGs) act as virtual firewalls for your Lambda's network interfaces within a VPC.
- They control inbound and outbound traffic at the instance (ENI) level.
- SGs are stateful: if you allow outbound traffic, the return inbound traffic is automatically allowed.
- You attach SGs directly to your Lambda function's ENIs when it's configured in a VPC.
SG Rules: Least Privilege
When setting up Security Group rules, always follow the principle of least privilege.
- Inbound Rules: Specify which traffic is allowed into your Lambda (e.g., from a database).
- Outbound Rules: Specify which traffic your Lambda is allowed to send out (e.g., to S3 or a database).
Only open ports and allow traffic from trusted sources or to necessary destinations.
Network ACLs (NACLs)
Network Access Control Lists (NACLs) provide an additional layer of security at the subnet level within your VPC.
- NACLs are stateless: you must explicitly allow both inbound and outbound return traffic.
- They can include both allow and deny rules, processed in order by rule number.
- NACLs apply to all resources within a subnet, including your Lambda's ENIs.
SG vs. NACL Comparison
Both Security Groups and NACLs filter network traffic, but they operate at different levels:
- Security Groups: Instance-level (ENI), stateful, allow rules only.
- NACLs: Subnet-level, stateless, allow & deny rules, processed by rule number.
Typically, you use SGs for granular control over specific resources and NACLs as a broader, coarser security layer for subnets.
Accessing AWS Services Privately
When your Lambda function is in a VPC, its traffic to public AWS services (like S3, DynamoDB, CloudWatch) would normally exit the VPC via a NAT Gateway or Internet Gateway.
This can introduce security risks and extra costs. VPC Endpoints allow private, secure communication to these services within your VPC.
Interface Endpoints Explained
Interface Endpoints (powered by AWS PrivateLink) provide a private connection to services using an Elastic Network Interface (ENI) in your VPC.
- They allow your Lambda to access services like S3, DynamoDB, and CloudWatch Logs without traversing the public internet.
- Traffic stays entirely within the AWS network, enhancing security and potentially reducing latency.
Endpoint Security
VPC Endpoints themselves can be secured:
- Endpoint Policies: You can attach IAM resource policies directly to an endpoint to control which principals can use it and what actions they can perform.
- Security Groups: For Interface Endpoints, you can associate a Security Group with the endpoint's ENIs. This SG controls traffic to and from the endpoint.
This ensures only authorized Lambda functions or resources can use the private connection.
Secure S3 Access Scenario
Imagine a Lambda function in a VPC that needs to upload files to an S3 bucket.
To do this securely and privately, you would:
- Configure the Lambda in a private subnet with specific Security Group rules.
- Set up an S3 Interface Endpoint in your VPC.
- Apply an Endpoint Policy to the S3 Endpoint and attach a Security Group to its ENIs.
This ensures S3 traffic never leaves the AWS private network.
Lambda S3 Interaction
This Python Lambda function uploads a simple text file to an S3 bucket. When deployed within a VPC, its network access to S3 would be governed by the Security Groups, Network ACLs, and VPC S3 Endpoint configured in your VPC.
import boto3
import os
def lambda_handler(event, context):
s3_client = boto3.client('s3')
bucket_name = os.environ.get('BUCKET_NAME', 'your-secure-bucket-name')
file_content = "Hello from a secure Lambda!"
file_name = "secure_lambda_output.txt"
try:
s3_client.put_object(Bucket=bucket_name, Key=file_name, Body=file_content)
return {
'statusCode': 200,
'body': f'Successfully uploaded {file_name} to {bucket_name}'
}
except Exception as e:
print(f"Error uploading to S3: {e}")
return {
'statusCode': 500,
'body': f'Failed to upload to S3: {str(e)}'
}
Network Security Check
Which of the following statements about network security for Lambda functions in a VPC are TRUE?
Recap & Best Practices
You've learned how to secure your Lambda functions within a VPC!
- Security Groups offer stateful, instance-level traffic control.
- Network ACLs provide stateless, subnet-level filtering.
- VPC Endpoints enable private access to other AWS services like S3 and DynamoDB.
Always apply the principle of least privilege to minimize your attack surface and keep your serverless applications secure.
常见问题解答
「网络安全最佳实践」课时是免费的吗？
是的 — 「网络安全最佳实践」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Serverless AWS Lambda Development 课程的其余内容，请升级到 CoddyKit PRO。 Serverless AWS Lambda Development 课程共包含 4 节课。
「网络安全最佳实践」这节课中我会学到什么？
使用安全组、网络 ACL 和私有端点，为 VPC 中的 Lambda 函数实施可靠的网络安全措施，尽量缩小攻击面 你通过在浏览器中直接运行的动手代码来练习 Serverless AWS Lambda Development，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 Serverless AWS Lambda Development 需要有经验吗？
无需任何先前经验。CoddyKit 上的 Serverless AWS Lambda Development 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 3 节课，共 4 节。
「网络安全最佳实践」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 Serverless AWS Lambda Development 课中编写并运行代码吗？
能。每节 Serverless AWS Lambda Development 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。