Application Programming Interface (API) provides developers and website owners with source code from existing applications which can then be repurposed for their (the developer’s) specific needs and integrated into existing business and site functions to improve user experience.
In short, API has become essential for online business, and anything essential quickly becomes a target for malicious actors.
If you are a developer or you are using APIs in various applications on your site, below are some of the most common API vulnerabilities, how they are targeted, and what you can do to help mitigate their potential damage.
Code injections are a favorite way for malicious actors to commandeer an API and have it do all manner of things that you or your client won’t want them to. The most common code injections include SQL, XML, and RegEx, and API, and they send commands to applications to do things like share sensitive user data, passwords, and other authentication information, and plant malware and spyware on devices.
One of the best ways to make sure that your API is fortified against code injections is to perform manual tests, and particularly intensive query checks, to determine if and how someone with bad intentions might go about inserting malicious code into an application.
Replay Request Attacks
This vulnerability pertains to those APIs that allow malicious actors to make repeated requests. This occurs when an API is not designed to prohibit future requests after a first untrustworthy request was recognized and rejected.
It is common for APIs to be designed in such a way that while they are able to successfully deny an initial, suspicious request, they do not prevent that same bad actor from continuing to make different requests.
These kinds of brute force attacks are commonly used to probe for vulnerabilities and can be guarded against by placing rate-limits on policies, utilizing HMAC authentication, employing multi-factor authentication, or utilizing OAuth access tokens with shorter life-spans.
Request Forgery Attacks
Request Forgery Attacks, or cross-site request forgery attacks, occur when a hacker attempts to use an authenticated web application (such as an API) to do things like alter an email address or send money from one bank account to another with the user finding out. These attacks have been popular for years, and have terrorized some of the internet’s biggest sites.
The most common way APIs are targeted with cross-site request forgeries is through the use of server-generated tokens that are placed in HTML code as “hidden fields.” These are returned to the server every time a request is made so that a server is able to determine whether a source is authenticated and therefore trustworthy. As more financial transactions continue to happen online, the risk of cross-site request forgery attacks increases.
Broken User Authentication
APIs and those creating them do not always make sure that authentication mechanisms function properly, or create them incorrectly, leaving the API extremely vulnerable. Faulty authentication mechanisms allow hackers to assume the identities of authenticated users, after which they can wreak all sorts of havoc. Sometimes the authentication system being used is not very robust and accidentally gives away an API key.
A good way to fortify your authentication process is, in addition to OAuth, to consider making use of a timestamp request. This can be added as a custom HTTP header in any API request, which forces the server to compare current and request timestamps. Authentication will only be valid if the server concludes that both of the timestamps are within a couple of minutes of one another.
APIs are prime targets because of how much damage can be done using relatively unsophisticated procedures. Because of this, those building and using APIs need to take the necessary precautions to ensure their and their customers’ information are not at risk because of these above common API vulnerabilities.