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.)
CWE-1022 Variant Incomplete
Use of Web Link to Untrusted Target with window.opener Access
This vulnerability occurs when a web application links to an external, untrusted site without protecting its own window from being manipulated by that site. Specifically, it fails to prevent the…
Definition
What is CWE-1022?
This vulnerability occurs when a web application links to an external, untrusted site without protecting its own window from being manipulated by that site. Specifically, it fails to prevent the external page from altering security-sensitive properties of the `window.opener` object, such as the page's location.
When a link with `target="_blank"` opens an external site in a new tab, the new page gains a reference back to the originating page via the `window.opener` object. If the external site is compromised or malicious, it can execute scripts that read or modify properties of the `window.opener` object. This cross-origin access allows an attacker to, for example, silently change the `location` property of your original page, redirecting it to a phishing site without the user's knowledge.
Since the user's focus is on the newly opened tab, the original tab performing the redirect may not be visible. This makes the attack particularly stealthy, as users are unlikely to notice their original page has been hijacked until they return to it, potentially after entering sensitive information on a spoofed site.
Real-world impact
Real-world CVEs caused by CWE-1022
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Library software does not use rel: "noopener noreferrer" setting, allowing tabnabbing attacks to redirect to a malicious page
How attackers exploit it
Step-by-step attacker path
- 1
In this example, the application opens a link in a named window/tab without taking precautions to prevent the called page from tampering with the calling page's location in the browser.
- 2
There are two ways that this weakness is commonly seen. The first is when the application generates an tag is with target="_blank" to point to a target site:
- 3
If the attacker offers a useful page on this link (or compromises a trusted, popular site), then a user may click on this link. However, the attacker could use scripting code to modify the window.opener's location property to redirect the application to a malicious, attacker-controlled page - such as one that mimics the look and feel of the original application and convinces the user to re-enter authentication credentials, i.e. phishing:
- 4
To mitigate this type of weakness, some browsers support the "rel" attribute with a value of "noopener", which sets the window.opener object equal to null. Another option is to use the "rel" attribute with a value of "noreferrer", which in essence does the same thing.
- 5
A second way that this weakness is commonly seen is when opening a new site directly within JavaScript. In this case, a new site is opened using the window.open() function.
Vulnerable code example
Vulnerable HTML
There are two ways that this weakness is commonly seen. The first is when the application generates an tag is with target="_blank" to point to a target site:
<a href="http://attacker-site.example.com/useful-page.html" target="_blank"> Attacker payload
If the attacker offers a useful page on this link (or compromises a trusted, popular site), then a user may click on this link. However, the attacker could use scripting code to modify the window.opener's location property to redirect the application to a malicious, attacker-controlled page - such as one that mimics the look and feel of the original application and convinces the user to re-enter authentication credentials, i.e. phishing:
window.opener.location = 'http://phishing.example.org/popular-bank-page'; Secure code example
Secure HTML
To mitigate this type of weakness, some browsers support the "rel" attribute with a value of "noopener", which sets the window.opener object equal to null. Another option is to use the "rel" attribute with a value of "noreferrer", which in essence does the same thing.
<a href="http://attacker-site.example.com/useful-page.html" target="_blank" rel="noopener noreferrer"> What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist
How to prevent CWE-1022
- 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 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.
Detection signals
How to detect CWE-1022
CWE-1022
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Frequently asked questions What is CWE-1022?
How serious is CWE-1022?
What languages or platforms are affected by CWE-1022?
How can I prevent CWE-1022?
How does Plexicus detect and fix CWE-1022?
Where can I learn more about CWE-1022?
Frequently asked questions
What is CWE-1022?
This vulnerability occurs when a web application links to an external, untrusted site without protecting its own window from being manipulated by that site. Specifically, it fails to prevent the external page from altering security-sensitive properties of the `window.opener` object, such as the page's location.
How serious is CWE-1022?
MITRE rates the likelihood of exploit as Medium — exploitation is realistic but typically requires specific conditions.
What languages or platforms are affected by CWE-1022?
MITRE lists the following affected platforms: JavaScript, Web Based.
How can I prevent CWE-1022?
Specify in the design that any linked external document must not be granted access to the location object of the calling page. 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.
How does Plexicus detect and fix CWE-1022?
Plexicus's SAST engine matches the data-flow signature for CWE-1022 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.
Where can I learn more about CWE-1022?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/1022.html. You can also reference OWASP and NIST documentation for adjacent guidance.
Related weaknesses
Weaknesses related to CWE-1022
CWE-266 Parent
Incorrect Privilege Assignment
This vulnerability occurs when a system mistakenly grants a user, process, or entity a specific permission or privilege they should not…
CWE-520 Sibling
.NET Misconfiguration: Use of Impersonation
This vulnerability occurs when a .NET application is configured to run with impersonation, potentially granting it excessive system-level…
CWE-556 Sibling
ASP.NET Misconfiguration: Use of Identity Impersonation
This vulnerability occurs when an ASP.NET application is configured to run using impersonated credentials, which can grant the application…
CWE-9 Sibling
J2EE Misconfiguration: Weak Access Permissions for EJB Methods
This vulnerability occurs when Enterprise JavaBean (EJB) methods are configured with overly permissive access rights, allowing attackers…
Resources
Further reading
- MITRE — official CWE-1022 https://cwe.mitre.org/data/definitions/1022.html
- Target="_blank" - the most underestimated vulnerability ever https://medium.com/@jitbit/target-blank-the-most-underestimated-vulnerability-ever-96e328301f4c
- The target="_blank" vulnerability by example https://dev.to/ben/the-targetblank-vulnerability-by-example
- About rel=noopener https://mathiasbynens.github.io/rel-noopener/
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