CVE-2015-0819 in Firefox
Summary
by MITRE
The UITour::onPageEvent function in Mozilla Firefox before 36.0 does not ensure that an API call originates from a foreground tab, which allows remote attackers to conduct spoofing and clickjacking attacks by leveraging access to a UI Tour web site.
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Analysis
by VulDB Data Team • 03/10/2022
The vulnerability identified as CVE-2015-0819 resides within the UITour::onPageEvent function of Mozilla Firefox versions prior to 36.0, representing a critical security flaw that undermines the browser's user interface protection mechanisms. This issue stems from insufficient validation of API call origins, creating a pathway for malicious actors to exploit the browser's interface tour functionality. The vulnerability specifically targets the lack of foreground tab verification, which is essential for maintaining the integrity of user interface interactions within the browser environment. According to CWE-668, this represents an "Exposure of Resource to Wrong Sphere" vulnerability where the UI tour API is accessible from unintended contexts, violating the principle of least privilege in security design.
The technical exploitation of this vulnerability enables remote attackers to perform sophisticated spoofing and clickjacking attacks by leveraging access to a malicious UI Tour website. Attackers can craft web pages that interact with Firefox's UI tour functionality without proper authorization, potentially deceiving users into performing unintended actions. The flaw occurs because the UITour::onPageEvent function fails to validate whether the API call originates from a foreground tab, allowing background or malicious tabs to execute interface commands that should only be available to legitimate foreground browser contexts. This vulnerability directly relates to the ATT&CK technique T1056.001 which covers "Input Injection: Keylogging" and T1203 which addresses "Exploitation for Client Execution" as it enables attackers to manipulate user interface elements and potentially capture user interactions.
The operational impact of this vulnerability extends beyond simple interface manipulation, as it provides attackers with the capability to create deceptive user experiences that can lead to more serious security breaches. When combined with other attack vectors, this flaw could enable credential theft, data exfiltration, or unauthorized access to sensitive browser functions. The vulnerability affects users who visit malicious websites that can leverage the UI tour API to display deceptive interfaces or manipulate browser behavior. Organizations and individuals using affected Firefox versions face significant risk, as the attack requires no local privileges or complex exploitation techniques, making it particularly dangerous for widespread deployment.
Mitigation strategies for CVE-2015-0819 primarily involve upgrading to Firefox version 36.0 or later, where the vulnerability has been addressed through proper validation of API call origins and enhanced foreground tab verification. Security administrators should implement comprehensive browser update policies and ensure all users maintain current versions of Firefox to prevent exploitation. Additional protective measures include deploying content security policies that restrict access to potentially malicious UI tour functionality, monitoring for suspicious web content that attempts to interact with browser interface elements, and educating users about the risks of visiting untrusted websites. Organizations should also consider implementing network-level controls that can detect and block malicious UI tour API usage patterns, as the vulnerability represents a persistent threat that can be exploited across multiple attack scenarios without requiring elevated system privileges or complex attack chains.