CWE-1022 Detail

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.

When a user clicks a link to an external site ("target"), the target="_blank" attribute causes the target site's contents to be opened in a new window or tab, which runs in the same process as the original page. The window.opener object records information about the original page that offered the link. 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 a malicious site, 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.

Modes Of Introduction

Architecture and Design : This weakness is introduced during the design of an application when the architect does not specify that a linked external document should not be able to alter the location of the calling page.
Implementation : This weakness is introduced during the coding of an application when the developer does not include the noopener and/or noreferrer value for the rel attribute.

Applicable Platforms

Language

Name: JavaScript (Often)

Technologies

Class: Web Based (Often)

Common Consequences

Observed Examples

Potential Mitigations

Phases : 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.
Phases : Implementation

When creating a link to an external document using the 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.

Phases : Implementation

Do not use "_blank" targets. However, this can affect the usability of the application.

Detection Methods

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.)
Effectiveness : High

Vulnerability Mapping Notes

Justification : This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comment : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

References

REF-39

Target="_blank" - the most underestimated vulnerability ever
Alex Yumashev.
https://medium.com/@jitbit/target-blank-the-most-underestimated-vulnerability-ever-96e328301f4c

REF-40

The target="_blank" vulnerability by example
Ben Halpern.
https://dev.to/ben/the-targetblank-vulnerability-by-example

REF-958

About rel=noopener
Mathias Bynens.
https://mathiasbynens.github.io/rel-noopener/

Submission

Modifications