What is Serverless Security?

Serverless security refers to the measures and practices put in place to protect serverless applications from potential threats. In a serverless architecture, developers can build and run applications without worrying about the underlying infrastructure. However, this convenience also introduces unique security concerns. Unlike traditional architectures, serverless applications have multiple event-driven functions, each potentially presenting an attack surface.

Serverless security, therefore, involves securing these individual functions by managing access controls, safeguarding from sensitive data exposure, monitoring application activity, and ensuring the code running on these functions is free from vulnerabilities. It’s a vital aspect of serverless computing that helps maintain the integrity, confidentiality, and availability of your applications.

For example, in AWS, you could use AWS Lambda functions for running your serverless applications. Here, the security responsibility is shared. AWS manages the security of the cloud – including the physical infrastructure, the server operating system, and the underlying capabilities of AWS Lambda. However, the security of what you put on the cloud – including the functions you write for AWS Lambda – is your responsibility.

Similarly, Microsoft Azure offers Azure Functions for building event-driven applications. While Azure takes care of the infrastructure security, users must ensure their function code is secure and free from vulnerabilities. They must also appropriately configure the function app settings and manage the identities and access controls effectively.

Google Cloud Platform (GCP) provides Google Cloud Functions as its serverless solution. As with AWS and Azure, Google manages the security of the underlying infrastructure, but users need to secure their function code and configurations.

Perform threat modeling to identify potential access points in your application.

Threat Modeling involves identifying potential access points or vulnerabilities in your application that could be exploited by attackers. The process starts with understanding the flow of data through your application, cloud provider and the various functions it interacts with. This helps in creating a visual representation (model) of the application’s operations, making it easier to pinpoint potential weak spots. Once these potential access points are identified, you can then analyze them to understand the types of threats they could be exposed to.

This might include unauthorized data access, injection attacks, or function-level denial of service attacks, among others. After identifying and understanding these threats, appropriate security measures can be implemented to mitigate them. This process of threat modeling is critical in a serverless environment due to its event-driven nature, which results in a large number of potential access points that need to be secured.

Restrict access to essential permissions only, to reduce the potential for privilege escalation risks.

In a serverless architecture, each function should be given the least amount of permissions necessary to perform its task. This principle, known as the Principle of Least Privilege (PoLP), significantly reduces the potential damage if a function is compromised. By limiting the permissions to what’s necessary, even if an attacker gains access to a function, they won’t have free reign over your system.

They can only access the limited resources that the compromised function can access. This approach requires careful planning and management of roles and access policies, but it’s a worthwhile investment in enhancing the security of your serverless applications.

Several services provided by cloud providers such as AWS, Azure, and Google Cloud Platform (GCP) can assist with this. AWS offers Identity and Access Management (IAM), which allows you to securely control access to AWS services and resources. Using IAM, you can create and manage AWS users and groups, and use permissions to allow or deny their access to AWS resources. On the other hand, Azure uses Azure Active Directory for identity services, which provides a comprehensive set of capabilities to manage users and groups, and define their access rights. Similarly, GCP has Cloud IAM, allowing administrators to authorize who can take action on specific resources, providing granular access security controls and ensuring that users possess only the necessary permissions.

Do not share IAM roles among other serverless functions

it’s important to avoid sharing Identity and Access Management (IAM) roles across multiple serverless functions. Doing so could potentially expose your application to unnecessary security risks. In the context of AWS, for example, each Lambda function should have its own distinct IAM role. This practice aligns with the principle of least privilege (PoLP), which states that each function or process should have only the permissions necessary to perform its intended task.

Sharing IAM roles between functions can inadvertently grant excessive permissions to a function that doesn’t require them, thereby increasing the potential for privilege escalation if an attacker compromises that function. By assigning unique IAM roles to each function, you can effectively limit the scope of permissions and reduce the overall attack surface of your serverless application.

Ensure all data inputs are sanitized and verified to avoid the risk of injection attacks.

Injection attacks, such as SQL injection, are common security threats where an attacker sends malicious data as part of a command or query that tricks the interpreter into executing unintended commands or accessing unauthorized data. To mitigate these risks, it’s crucial to sanitize and verify all data inputs. Sanitizing involves removing or replacing characters in the input that have special meaning in the target interpreter context, thus neutralizing any potentially harmful effects.

Verification, on the other hand, involves checking the data to ensure it conforms to the expected format, type, length, pattern, and range. Implementing strict input validation rules can help prevent attackers from injecting malicious code. Additionally, use parameterized queries or prepared statements, which can automatically sanitize input and prevent injection attacks.

Implement API gateways as an additional security layer for enhanced protection.

Implementing API gateways as an additional security layer is a strategic move towards enhancing the protection of serverless applications. An API gateway serves as a critical intermediary between your application components and the outside world. It can handle multiple tasks, including routing requests, transforming protocols, aggregating data, and most importantly, offering robust security mechanisms.

API gateways can provide features such as identity and access control, rate limiting, and IP filtering. They can authenticate and authorize users, preventing unauthorized access to your serverless functions. Rate limiting can protect your system from Denial of Service (DoS) attacks by limiting the number of requests that a user or IP address can send in a specific time frame. IP filtering can block traffic from suspicious or malicious IPs.

In addition, API gateways can validate input and output formats, ensuring only safe and expected data is processed by your functions. Lastly, they can monitor and log activity, helping you detect any unusual patterns or potential threats. By adopting an API gateway, you add an extra layer of security that helps secure your serverless architecture from various attack vectors.

Managing application secrets securely

Application secrets, such as API keys, database usernames and passwords, and encryption keys, are sensitive pieces of information that, if exposed, can lead to significant security breaches. Therefore, it’s essential to store these secrets safely. One effective way to do this is by using secret management services that store your sensitive data securely, encrypting it both in transit and at rest. Never embed secrets or environment variables directly into the codebase or version control systems, as this practice exposes them to unnecessary risk. Instead, inject secrets into the application environment at runtime.

Additionally, implement least privilege access principles, ensuring each part of your application only has access to the secrets it needs to function. Regularly rotating these secrets and monitoring their usage can also help prevent or detect unauthorized access. By following these practices, you can ensure the secure handling of application secrets, contributing significantly to your overall serverless application security.

  • AWS: On AWS, you can use the AWS Secrets Manager service, which encrypts secrets at rest and in transit. It also allows for automatic rotation of secrets, limiting their life span and reducing the risk if they are compromised.

  • Azure: Azure provides a similar service called Azure Key Vault. This service lets you securely store and tightly control access to tokens, passwords, certificates, API keys, and other secrets. It also supports logging of all interactions for auditing purposes.

  • GCP: On GCP, the Secret Manager service offers a secure and convenient method for storing API keys, passwords, certificates, and other sensitive data. This service provides versioning for secrets, enabling easy rollback and tracking of changes.

Implement Web Application Firewalls for extra security precautions.

Implementing Web Application Firewalls (WAF) is an additional security measure that can significantly enhance the safety of serverless applications. A WAF is a protective layer that sits between your application and the internet, inspecting incoming traffic for malicious activity such as SQL injection, cross-site scripting (XSS), and Distributed Denial of Service (DDoS) attacks.

Many cloud service providers offer integrated WAF services, such as AWS WAF, Azure WAF, and Google Cloud Armor, which are designed to work seamlessly with their respective serverless platforms. These services typically provide customizable security rules, allowing you to define the conditions under which the firewall should block, allow, or monitor web requests.

Additionally, they often include features like threat intelligence feeds and automated rule updates,helping you stay ahead of the latest threats. Implementing a WAF not only helps protect your serverless applications from common web-based attacks but also provides valuable insights into attempted attacks, aiding in ongoing security efforts.

Ensure that all function dependencies are regularly updated with the most recent security patches.

Ensuring that all function dependencies are regularly updated with the most recent security patches is an integral part of securing serverless applications. Serverless architectures rely heavily on third-party services and libraries, which can become a potential security risk if they are not kept up to date. Neglected or outdated dependencies can have known vulnerabilities that can be easily exploited by attackers.

Therefore, it’s crucial to implement a robust process for regularly updating these dependencies and applying the latest security patches. This not only helps in fixing known security loopholes but also enhances the overall performance and reliability of your serverless application.

There are third-party tools, such as Snyk and Dependabot, that can monitor your dependencies and notify you of any known vulnerabilities or available updates. By ensuring regular updates and applying the latest security patches, you can mitigate potential security risks and maintain the integrity of your serverless applications.

Consistently track and document function activities to identify any possible security intrusions.

This process involves monitoring every transaction and operation within your serverless applications, including data access, function modifications, and configuration changes. By doing so, you can spot any unusual behavior patterns or anomalies that may signal a potential security intrusion. This level of vigilance allows for quick detection and response to threats, effectively reducing the potential damage from cyber attacks.

Furthermore, maintaining a comprehensive log of these activities aids in post-incident forensic analysis, helping to pinpoint how an intrusion occurred and informing future strategies to prevent similar breaches.

There are various tools available, such as AWS CloudWatch, Google Cloud’s Operations Suite, or Azure Monitor, which can automate this tracking and documentation process, ensuring a robust and real-time defense mechanism for your serverless applications.

Implement secure coding practices during the application development process.

Secure coding practices involves the integration of security measures at every stage of the development lifecycle, not merely as a final step or an afterthought. This includes practices such as validating input to mitigate injection attacks, handling errors correctly to avoid unintentional leakage of sensitive data, and employing encryption techniques for protecting data both at rest and in transit.

Regular code reviews, coupled with automated testing, can help detect and rectify vulnerabilities early on. Tools like Static Application Security Testing (SAST) and Dynamic Application Security Testing (DAST) can assist in automating these checks, making the process more efficient.

Make sure that data transmission is both protected and verified.

Protection of data during transmission involves implementing robust encryption measures, typically using protocols such as Transport Layer Security (TLS) or Secure Sockets Layer (SSL). These protocols encrypt data before it’s transmitted and then decrypt it upon receipt, thereby safeguarding the data from unauthorized access during transit.

On the other hand, verification of data entails confirming the integrity and authenticity of the received data to ensure it hasn’t been altered during transmission. This can be achieved through techniques like digital signatures and checksums.

An additional layer of security can be added by employing mutual TLS (mTLS),which not only encrypts data but also authenticates the identities of both the sender and receiver. By ensuring that data transmission is both protected and verified, you can significantly enhance the security of your serverless applications.

Keep confidential data in a protected place

Encryption at rest is a critical security measure that converts data into an unreadable format, decipherable only with a decryption key. This means that even if unauthorized individuals gain access to the storage, they cannot interpret the data without this key.

In AWS, services such as Amazon S3Amazon RDS, and Amazon DynamoDB provide built-in encryption at rest. When using these services, it’s essential to manage your keys securely using AWS Key Management Service (KMS). Only trusted entities should have access to these keys, and they should be periodically rotated to mitigate the risk of compromise.

Perform penetration testing on your serverless applications.

Performing penetration testing on your serverless applications is a crucial step in securing them against potential threats. Penetration testing, also known as pen testing, involves simulating cyber attacks to identify vulnerabilities that could be exploited by malicious hackers. For serverless applications, this means examining the multiple functions, triggers, and resources to spot any security weaknesses. It’s essential to test all aspects of your application, from the API Gateway, Lambda functions, to third-party services your application depends on.

Automated tools can be used to streamline this process, but manual testing is also necessary for a comprehensive assessment. It’s recommended to engage a professional ethical hacker or a specialized security firm to conduct these tests, as they have the expertise to mimic sophisticated attack patterns accurately.

After identifying vulnerabilities, you must promptly address them and retest to ensure their effective mitigation. Regular pen-testing is recommended as new vulnerabilities can emerge with code changes or updates.

Examine the business logic processes of the application.

Business logic vulnerabilities are unique to each application and often overlooked by traditional security measures. They occur when an attacker manipulates the expected behavior of your application, leading to unauthorized access or data breaches. For instance, an e-commerce app might have a business logic process that allows users to add items to a cart and checkout.

A vulnerability could exist if a user can manipulate the system to checkout with negative quantities, leading to a credit instead of a charge. To secure your serverless applications, you need to understand all aspects of your application’s business logic thoroughly. This means mapping out all the application’s functionalities, associated data flows, and user privileges.


In conclusion, securing serverless applications involves a multi-faceted approach. As these processes can be complex and require specialized knowledge, organizations can benefit from partnering with a security consulting like Securinc to help with their serverless security challenges.

Securinc’s comprehensive serverless security best practices consultation can help organizations identify potential vulnerabilities in their business logic and implement the necessary measures to mitigate them. With their expertise, organizations can secure their serverless applications, protect their data, and maintain the integrity of their operations.

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