· Mar 13, 2021 5m read

Protect your REST API applying OWASP Top Ten

Hi Community,

Did you know about OWASP and Top Ten Web Application security risks to your Web API or Web Apps?

OWASP is a community foundation created to help us to improve the security of web apps/web APIs. OWASP do the web apps more secure through its community-led open source software projects, hundreds of chapters worldwide, tens of thousands of members, and by hosting local and global conferences.

To summarize the top procedures to do your web app/web api more secure OWASP published the "Top 10 Web Application Security Risks" recomendations, see (source:

  1. Injection. Injection flaws, such as SQL, NoSQL, OS, and LDAP injection, occur when untrusted data is sent to an interpreter as part of a command or query. The attacker’s hostile data can trick the interpreter into executing unintended commands or accessing data without proper authorization.
  2. Broken Authentication. Application functions related to authentication and session management are often implemented incorrectly, allowing attackers to compromise passwords, keys, or session tokens, or to exploit other implementation flaws to assume other users’ identities temporarily or permanently.
  3. Sensitive Data Exposure. Many web applications and APIs do not properly protect sensitive data, such as financial, healthcare, and PII. Attackers may steal or modify such weakly protected data to conduct credit card fraud, identity theft, or other crimes. Sensitive data may be compromised without extra protection, such as encryption at rest or in transit, and requires special precautions when exchanged with the browser.
  4. XML External Entities (XXE). Many older or poorly configured XML processors evaluate external entity references within XML documents. External entities can be used to disclose internal files using the file URI handler, internal file shares, internal port scanning, remote code execution, and denial of service attacks.
  5. Broken Access Control. Restrictions on what authenticated users are allowed to do are often not properly enforced. Attackers can exploit these flaws to access unauthorized functionality and/or data, such as access other users’ accounts, view sensitive files, modify other users’ data, change access rights, etc.
  6. Security Misconfiguration. Security misconfiguration is the most commonly seen issue. This is commonly a result of insecure default configurations, incomplete or ad hoc configurations, open cloud storage, misconfigured HTTP headers, and verbose error messages containing sensitive information. Not only must all operating systems, frameworks, libraries, and applications be securely configured, but they must be patched/upgraded in a timely fashion.
  7. Cross-Site Scripting (XSS). XSS flaws occur whenever an application includes untrusted data in a new web page without proper validation or escaping, or updates an existing web page with user-supplied data using a browser API that can create HTML or JavaScript. XSS allows attackers to execute scripts in the victim’s browser which can hijack user sessions, deface web sites, or redirect the user to malicious sites.
  8. Insecure Deserialization. Insecure deserialization often leads to remote code execution. Even if deserialization flaws do not result in remote code execution, they can be used to perform attacks, including replay attacks, injection attacks, and privilege escalation attacks.
  9. Using Components with Known Vulnerabilities. Components, such as libraries, frameworks, and other software modules, run with the same privileges as the application. If a vulnerable component is exploited, such an attack can facilitate serious data loss or server takeover. Applications and APIs using components with known vulnerabilities may undermine application defenses and enable various attacks and impacts.
  10. Insufficient Logging & Monitoring. Insufficient logging and monitoring, coupled with missing or ineffective integration with incident response, allows attackers to further attack systems, maintain persistence, pivot to more systems, and tamper, extract, or destroy data. Most breach studies show time to detect a breach is over 200 days, typically detected by external parties rather than internal processes or monitoring.

Some techniques could be used to implement OWASP top ten, see the table:

OWASP Recomentation Resources

In SQL use input parameters specified using the “?” character or input host variables (for example, :var). Avoid concatenate SQL instructions and input method arguments.
Use Sanitazer API like

Broken Authentication

Create strong passwords, see Microsoft doc:

Don't use passwords inside source code, encrypt it, use vault services or SSO services.

Externalize your passwords using parameters from the Docker/OS environment

Don't allow brute force attacks using API gateways like IAM:

Sensitive Data Exposure Avoid return Credit card data, health data and another sensitive data in your API, if not possible, encrypt message channels and the sensitive data storage. Minimize the data collect to the minimal as possible.
XXE Use %XMLAdaptor
Broken Access Control Use access management tools like like IAM:
Security Misconfiguration

Update your software periodically and run pentest software in your environment to take the appropriate procedures.

Follow the Security Administration Guide from intersystems:

XSS Do the input sanitization/validation, see OWASP tips:
Insecure deserialization Create hash to files, create safer folders with no execution permission to store files and validate files extensions
Using Components with Known Vulnerabilities In the InterSystems stack Apache Web Server is the most known tool, so take care to configure it to the production, following this: Enable your OS firewall, to ubuntu run ufw enable (see:
Insufficient Logging & Monitoring

Use Log Monitor (

Follow it:

Monitor using SAM:

You can use WAF software in alignment with OWASP Top ten, see: or use InterSystems IAM. From G2 list, I like 42 crunch, that allows a free account and you appoint your OpenAPI file and it is analyzed to report recomendations, see in

Discussion (2)3
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@Yuri Marx there's actually a separate "API Security Top 10" which is particularly relevant for REST APIs and modern web applications:

API4, API9, and API10 are all good IAM use cases; for the others, I'd recommend looking at for a security-first generic REST API implementation.