Input Validation (Requests Sanitizer)

Bonita REST API can be secured against XSS attacks with a request sanitizer.

Cross-Site Scripting (also known as XSS), is a common example of web security vulnerability. An attacker can compromise the interactions that users have with a vulnerable application. By injecting some malicious code then executed on a user’s browser, the attacker can impersonate this user and take illegitimate control on the application.

To prevent such attacks, Bonita REST API can be secured with a requests sanitizer which neutralizes malicious code from the body of incoming requests.

Default security setup in Bonita

In Bonita, the UI screens are secured in order to prevent XSS attacks.

Since version 2022.1u8 (7.14.8) in 2024, in addition to UI screens protections, a Sanitizer protection is available to filter harmful payloads out of API requests. This additional security helps preventing stored XSS attacks on screens which may have not been secured enough, such as custom pages you have developed.

How it works

On potentially harmful REST API requests, a filter executes the OWASP Java HTML Sanitizer on the request body. Malicious code is then removed or escaped from the request body before the request is handled.

When you migrate from a previous version and activate the sanitizer protection, since it filters the request’s inputs, it will not protect your unsecured UI screens from XSS attacks which have already been stored in the database.

How to see if content has been filtered?

In order to see what has been impacted by the Sanitizer, you need to set the following Log4j2 log level to DEBUG in file <BUNDLE_HOME>/server/conf/log4j2-loggers.xml.

    <Logger name="org.bonitasoft.console.common.server.filter.SanitizerFilter" level="DEBUG"/>

Is there a functional impact?

If you are displaying code in Bonita Applications, this may have a functional impact for you. The code you wish to just display may be considered as some malicious injected code and removed from the input, or some character sequences may be replaced by unescaped equivalent. E.g. a comment such as

My page contains "&amp;" and "1 &lt; 3" and "<script>alert(1)</script>"

will be displayed as

My page contains "&" and "1 < 3" and ""

How do I enable/disable it?

When the Sanitizer protection is enabled, it applies to the whole platform REST API, but it can be disabled partially for some specific json attributes. Enabling the Sanitizer protection is recommended, however it is safe to disable it for some specific json attributes when:

  • the value is expected to contain special characters

  • and either:

    • the value is already checked (e.g. email with a pattern)

    • or the value is never interpreted (or displayed) in pages (e.g. password).

The Sanitizer protection can be activated/deactivated in the file The default version of this file is located in setup/platform_conf/initial/platform_portal. In order to change the configuration on an installation whose platform has already been initialized, use the platform setup tool to retrieve the current configuration and update the file in setup/platform_conf/current/platform_portal. Then use the tool again to save your changes into to the database.

When the Sanitizer protection is disabled, this file contains this line: security.sanitizer.enabled false

To enable it, change the value to true

By default Sanitizer protection is disabled on a few json attributes with this line: security.sanitizer.exclude email,password,password_confirm

If you want to disable the Sanitizer protection for a specific json attribute, edit the configuration file and append your attribute name to the security.sanitizer.exclude comma-separated values.

In either case, make sure all your concerned UI pages are secured against XSS attacks before disabling the Sanitizer protection (e.g. by developing them with Bonita UI Designer and avoiding using the allow HTML option of the widgets when the content comes from a user input).