CWE-1021: Improper Restriction of Rendered UI Layers or Frames
The web application does not restrict or incorrectly restricts frame objects or UI layers that belong to another application or domain, which can lead to user confusion about which interface the user is interacting with.
View on MITREExtended Description
A web application is expected to place restrictions on whether it is allowed to be rendered within frames, iframes, objects, embed or applet elements. Without the restrictions, users can be tricked into interacting with the application when they were not intending to.
Technical Details
- Structure
- Simple
Applicable To
Security Consequences
Scope
Impact
An attacker can trick a user into performing actions that are masked and hidden from the user's view. The impact varies widely, depending on the functionality of the underlying application. For example, in a social media application, clickjacking could be used to trik the user into changing privacy settings.
Mitigation Strategies
Phase
Description
The use of X-Frame-Options allows developers of web content to restrict the usage of their application within the form of overlays, frames, or iFrames. The developer can indicate from which domains can frame the content. The concept of X-Frame-Options is well documented, but implementation of this protection mechanism is in development to cover gaps. There is a need for allowing frames from multiple domains.
Phase
Description
A developer can use a "frame-breaker" script in each page that should not be framed. This is very helpful for legacy browsers that do not support X-Frame-Options security feature previously mentioned. It is also important to note that this tactic has been circumvented or bypassed. Improper usage of frames can persist in the web application through nested frames. The "frame-breaking" script does not intuitively account for multiple nested frames that can be presented to the user.
Phase
Description
This defense-in-depth technique can be used to prevent the improper usage of frames in web applications. It prioritizes the valid sources of data to be loaded into the application through the usage of declarative policies. Based on which implementation of Content Security Policy is in use, the developer should use the "frame-ancestors" directive or the "frame-src" directive to mitigate this weakness. Both directives allow for the placement of restrictions when it comes to allowing embedded content.
Detection Methods
No detection method information available for this CWE.
Code Examples & CVEs
Observed CVE Examples (6)
E-mail preview feature in a desktop application allows clickjacking attacks via a crafted e-mail message
View DetailsHardware/firmware product has insufficient clickjacking protection in its web user interface
View DetailsTapjacking in permission dialog for mobile OS allows access of private storage using a partially-overlapping window.
View DetailsTapjacking in web browser related to page navigation and touch/gesture events.
View DetailsSystem UI in mobile OS allows a malicious application to create a UI overlay of the entire screen to gain privileges.
View DetailsCWE Relationships
No relationship information available for this CWE.
Frequently Asked Questions
What is CWE-1021: Improper Restriction of Rendered UI Layers or Frames?+
CWE-1021: Improper Restriction of Rendered UI Layers or Frames is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The web application does not restrict or incorrectly restricts frame objects or UI layers that belong to another application or domain, which can lead to user confusion about which interface the user is interacting with. A web application is expected to place restrictions on whether it is allowed to be rendered within frames, iframes, objects, embed or applet elements. Without the restrictions, users can be tricked into interacting with the application when they were not intending to.
What are the security consequences of Improper Restriction of Rendered UI Layers or Frames?+
If exploited, CWE-1021 (Improper Restriction of Rendered UI Layers or Frames) it can compromise Access Control, leading to outcomes such as Gain Privileges or Assume Identity, Bypass Protection Mechanism, Read Application Data and Modify Application Data.
How do you prevent or mitigate Improper Restriction of Rendered UI Layers or Frames?+
Recommended mitigations for CWE-1021 include: The use of X-Frame-Options allows developers of web content to restrict the usage of their application within the form of overlays, frames, or iFrames. The developer can indicate from which domains can frame the content. The concept of X-Frame-Options is well documented, but implementation of this protection mechanism is in development to cover gaps. There is a need for allowing frames from multiple domains. A developer can use a "frame-breaker" script in each page that should not be framed. This is very helpful for legacy browsers that do not support X-Frame-Options security feature previously mentioned. It is also important to note that this tactic has been circumvented or bypassed. Improper usage of frames can persist in the web application through nested frames. The "frame-breaking" script does not intuitively account for multiple nested frames that can be presented to the user. This defense-in-depth technique can be used to prevent the improper usage of frames in web applications. It prioritizes the valid sources of data to be loaded into the application through the usage of declarative policies. Based on which implementation of Content Security Policy is in use, the developer should use the "frame-ancestors" directive or the "frame-src" directive to mitigate this weakness. Both directives allow for the placement of restrictions when it comes to allowing embedded content.
What are real-world examples of Improper Restriction of Rendered UI Layers or Frames?+
MITRE documents real CVEs mapped to CWE-1021, including CVE-2017-7440, CVE-2017-5697, CVE-2017-4015, CVE-2016-2496 and CVE-2015-1241. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.
What is the difference between a CWE and a CVE?+
A CWE (Common Weakness Enumeration) like CWE-1021 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.