AjaxNetProfessional deserializes arbitrary JavaScript objects

Overview

Affected versions of this package are vulnerable to Deserialization of Untrusted Data due to the possibility of deserialization of arbitrary JavaScript objects.

Description

Cross-Site Scripting (XSS) attacks are a type of injection, in which malicious scripts are injected into otherwise benign and trusted websites. XSS attacks occur when an attacker uses a web application to send malicious code, generally in the form of a browser side script, to a different end user. Flaws that allow these attacks to succeed are quite widespread and occur anywhere a web application uses input from a user within the output it generates without validating or encoding it.

XSS effects vary in range from petty nuisance to significant security risk, depending on the sensitivity of the data handled by the vulnerable site and the nature of any security mitigation implemented by the site's owner network.

Releases

Releases before version 21.12.22.1 are affected. Please be careful to download any binary DLL from other web sites, especially we found NuGet packages not owned by us that contain vulnerable versions.

Workarounds

A workaround exists that replaces one of the core JavaScript files embedded in the library. Using a XML configuration allows to replace the default JavaScript code to be replaced with the version on GitHub.

<configuration>
	<configSections>
		<sectionGroup name="ajaxNet">
			<section name="ajaxSettings" type="AjaxPro.AjaxSettingsSectionHandler,AjaxPro.2" requirePermission="false" restartOnExternalChanges="true"/>
		</sectionGroup>
	</configSections>
	<ajaxNet>
		<ajaxSettings>
			<coreScript>~/ajaxpro-core-fixed.js</coreScript>
		</ajaxSettings>
	</ajaxNet>
</configuration>

Copy the file core.js from the main project folder to your web server root folder and rename that ajaxpro-core-fixed.js.

Clients need to refresh the web page to download the changed JavaScript code.

References

Commit fixing the issue: c89e39b9679fcb8ab6644fe21cc7e652cb615e2b

Note: the official Ajax.NET Professional (AjaxPro) NuGet package is available here: https://www.nuget.org/packages/AjaxNetProfessional/

For more information

If you have any questions or comments about this advisory:

• Open an issue on this GitHub repository