Bruno is an open source IDE for exploring and testing APIs. A bug in the assertion runtime caused assert expressions to run in Developer Mode, even if Safe Mode was selected. The bug resulted in the sandbox settings to be ignored for the particular case where a single request is run/sent. This vulnerabilitys attack surface is limited strictly to scenarios where users import collections from untrusted or malicious sources. The exploit requires deliberate action from the user—specifically, downloading and opening an externally provided malicious Bruno collection. The vulnerability is fixed in 1.39.1.
The product uses a cross-domain policy file that includes domains that should not be trusted.
A cross-domain policy file (“crossdomain.xml” in Flash and “clientaccesspolicy.xml” in Silverlight) defines a list of domains from which a server is allowed to make cross-domain requests. When making a cross-domain request, the Flash or Silverlight client will first look for the policy file on the target server. If it is found, and the domain hosting the application is explicitly allowed to make requests, the request is made. Therefore, if a cross-domain policy file includes domains that should not be trusted, such as when using wildcards, then the application could be attacked by these untrusted domains. An overly permissive policy file allows many of the same attacks seen in Cross-Site Scripting (CWE-79). Once the user has executed a malicious Flash or Silverlight application, they are vulnerable to a variety of attacks. The attacker could transfer private information, such as cookies that may include session information, from the victim’s machine to the attacker. The attacker could send malicious requests to a web site on behalf of the victim, which could be especially dangerous to the site if the victim has administrator privileges to manage that site. In many cases, the attack can be launched without the victim even being aware of it.