From the attacker’s perspective, one of the crucial time-consuming components of planning a community assault is the reconnaissance required to search out potential community assault vectors. Since software programming interfaces (APIs) should be uncovered to the general public, the period of time the attacker spends discovering assault vectors into the API’s community is drastically lowered, making APIs a better goal for potential breaches. The usage of APIs can enhance the assault floor of a community, and, if not designed accurately, they may end up in vital safety points.
The rise in implementing microservice architectures instead of monolithic software program architectures now makes APIs extra frequent than ever. To facilitate implementation of a zero belief technique in a community, this pervasiveness requires a centered effort to determine API-specific vulnerabilities. On this weblog put up, which is excerpted from a just lately revealed paper, I current three high API safety dangers together with suggestions for mitigating them.
Earlier than delving into the highest API dangers, it is very important perceive how they’re constructed.
API Endpoints
An API gives a programmed entry level into an software. If the applying is designed to work together with different functions, then an API is put into place to allow that interplay. Inside every API, there are a number of software connection factors known as endpoints.
Every endpoint serves a distinct objective, however they’re all related to the identical software. The next are a couple of examples of how an API endpoint could be used:
- logins (The mandatory inputs for that endpoint are a username and password.)
- password resets (The required enter would possibly solely be an e mail, so a password reset hyperlink will be despatched.)
- directors altering software settings (The required enter for entry could be a username and password.)
- enabling interplay between microservices (The required inputs could be person IDs or different person info, product or order info, or entire knowledge construction objects.)
Microservice Architectures
Over the previous decade, microservice architectures have turn out to be extra fashionable for newly designed techniques in comparison with the beforehand dominant monolithic architectures.
Microservice architectures concentrate on creating many small, loosely coupled micro functions to supply a bigger software. For instance, an organization may need a product descriptions microservice, a cost processing microservice, and a login microservice. Every of those microservices will be executed and deployed independently of the others. Every microservice has its personal API and endpoints for client-to-microservice or microservice-to-microservice interactions.
The distributed, loosely coupled design of those microservice architectures enable them to have higher scalability, flexibility, and steady deployments when in comparison with monolithic architectures. In keeping with Nationwide Institute of Requirements and Know-how (NIST) particular publication (SP) 800-204, “Microservices typically talk with one another utilizing Software Programming Interfaces (APIs), which require a number of core options to assist advanced interactions between a considerable variety of parts.” There are sometimes assist constructions that additionally assist API ecosystems by providing options, resembling API gateways and service meshes. Whereas this weblog put up and the paper from which this was excerpted solely focus on APIs, the use and configuration of supporting constructions (e.g., identification entry administration [IAM] servers, API gateways, service meshes) are additionally necessary to total API safety.
The rest of this put up will define three API safety dangers (third-party software program integrations, cascading failures, and elevated community assault floor) and supply suggestions for mitigating them.
Third-Occasion Software program Integrations
Description. Typically when creating new software program, together with APIs, current software program packages and libraries are used to make the design and implementation course of sooner and simpler. Nonetheless, integrating third-party software program means introducing all of the potential vulnerabilities of that software program into the brand new API that’s being constructed. Even the best high quality code can have as much as 600 defects per million traces of code whereas common high quality code has round 6,000 defects per million traces of code. Many of those defects may end up in vulnerabilities.
Instance. Log4J is a crucial vulnerability within the Java-based logging library that was found in 2022. It permits distant code execution and the entire takeover of the sufferer’s machine. Any system that has Log4j built-in into its software program is susceptible to assault till the vulnerability is patched.
Suggestions. The next suggestions apply to this danger.
- Carry out danger assessments on all third-party software program that could be utilized in a brand new API to forestall introducing further API vulnerabilities.
- Keep knowledgeable in regards to the newest vulnerabilities in all third-party software program that’s built-in into at present deployed APIs.
- Use automated vulnerability scanners on third-party software program if potential.
- Contemplate implementing a software program invoice of supplies framework to assist safe the availability chain and mitigate the dangers of utilizing third-party software program.
Cascading Failures
Description. As beforehand talked about, APIs are carefully tied to microservices, that are small functions designed to carry out a selected operate. These microservices ought to be loosely coupled with excessive cohesion, which signifies that every of them works independently or largely independently from different microservices. Designing the microservice structure with unbiased functions prevents the complete API ecosystem from shutting down if a single microservice turns into damaged or nonfunctional.
Designing the microservice structure with loosely coupled parts reduces the danger of API shut downs if a single microservice turns into damaged or nonfunctional. When one microservice’s inoperability causes points with different microservices, it’s known as cascading failures, and it ought to be averted to cut back the danger of DoS assaults on the API.
Instance. As illustrated in determine 1 under, assume a gross sales info API should name a product description API to finish a shopper request it receives from the API gateway, but in addition assume that the product description API goes down. On this case, the gross sales info microservice can not full its request. Because of this, the gross sales info software can’t be used as a result of one other software it depends on is down.
Suggestions. The next suggestions apply to this danger.
- Design APIs with the aim of unfastened coupling in thoughts, together with deployment coupling, temporal coupling, and implementational coupling.
- Create API documentation that clearly reveals which APIs are coupled and the communication circulation that occurs between coupled microservices. This documentation will probably be helpful for testing and troubleshooting if there are points with the API after deployment.
- Conduct unit testing, integration testing, and end-to-end testing to verify the proper performance of the microservice structure in accordance with the documented design.
- Attempt to forestall single factors of failure within the API community by including redundancy measures in authentication and authorization factors and different community constructions.
Elevated Community Assault Floor
Description. Microservice architectures that closely use APIs have many structural variations when in comparison with monolithic architectures. These variations can typically enhance the general community assault floor. Many non-microservice architectures have an online server in a demilitarized zone (DMZ) with a backend service one layer behind it that incorporates the database the API is accessing one layer behind that. This construction gives extra protection in depth in comparison with microservices that may collapse this layered method, which ends up in extra publicity.
Monolithic API architectures expose fewer IP-addressable distant process calls in comparison with microservice architectures. The result’s that these microservice architectures typically have a bigger assault floor as famous right here. There are additionally many assist constructions, just like the service discovery mechanism, wanted to create a safe microservice system that creates extra avenues for potential compromise if they’re tampered with. Microservice architectures are typically extra advanced than monolithic architectures, which will increase the chance of missed checks and misconfigurations that result in vulnerabilities.
Instance. Assume a microservice structure at present has 10 API endpoints supported by one API gateway with a transactions per second (TPS) charge restrict of 100 per second. If 10 extra API endpoints are added with the identical TPS charge restrict, meaning the identical variety of shoppers as earlier than can now produce twice as many transactions in the identical period of time among the many APIs. This might result in delays within the API gateway processing the elevated variety of transactions, leading to decreased customer support.
Suggestions. The next suggestions apply to this danger.
- Rigorously plan API versioning and deployments. Be strategic about including new APIs so the upkeep and stock of the present APIs don’t turn out to be overwhelming.
- Add redundancy measures to forestall overload from API use in assist constructions, such because the API gateway and authentication servers.
- Keep a radical stock of all APIs, ideally by auto-generated documentation for uniformity and searchability.
- Configure thorough logging and monitoring efforts for all API exercise, together with logging all authentication and enter failures.
Future Work: API Finest Practices
APIs are more and more frequent, and they’re typically designed and carried out in a method that creates safety dangers. This weblog put up, and the report from which it was excerpted, summarized three dangers related to APIs and offered suggestions about fixing or lowering their affect. A number of the most typical suggestions embrace the next:
- having a normal API documentation course of
- utilizing automated testing all through the event course of
- making certain the identification and entry administration system is safe
Future work might lengthen the findings on this report back to (1) discover integrating zero belief measures into the design of APIs and the event course of and (2) create a algorithm and suggestions for API greatest practices.
