CWE-1022 Use of Web Link to Untrusted Target with window.opener Access

The web application produces links to untrusted external sites outside of its sphere of control, but it does not properly prevent the external site from modifying security-critical properties of the window.opener object, such as the location property.

• Confidentiality: Alter Execution Logic — If an attacker can run script on the target page, then they could read or modify certain properties of the window.opener object, including the location property - even if the original and target site are not the same origin. An attacker can modify the location property to automatically redirect the user to an untrusted page that contains undesired content or malicious script code, e.g. as part of a phishing attack. Since this redirect happens in the original window/tab - which is not necessarily visible, since the browser is focusing the display on the new target page - the user might not notice any suspicious redirection.

• [Architecture and Design] Specify in the design that any linked external document must not be granted access to the location object of the calling page. • [Implementation] When creating a link to an external document using the <a> tag with a defined target, for example "_blank" or a named frame, provide the rel attribute with a value "noopener noreferrer". If opening the external document in a new window via javascript, then reset the opener by setting it equal to null. • [Implementation] Do not use "_blank" targets. However, this can affect the usability of the application.

• Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

• CVE-2022-4927: Library software does not use rel: "noopener noreferrer" setting, allowing tabnabbing attacks to redirect to a malicious page