CVE-2015-4476 in Firefox
Summary
by MITRE
Mozilla Firefox before 41.0 on Android allows user-assisted remote attackers to spoof address-bar attributes by leveraging lack of navigation after a paste of a URL with a nonstandard scheme, as demonstrated by spoofing an SSL attribute.
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Analysis
by VulDB Data Team • 06/18/2022
This vulnerability exists in Mozilla Firefox versions prior to 41.0 on Android platforms where attackers can exploit a flaw in the browser's handling of URL navigation following paste operations. The core technical issue stems from the browser's insufficient validation and handling of nonstandard URL schemes when users paste addresses into the address bar. When a user pastes a URL containing a nonstandard scheme, the browser fails to properly navigate or validate the input before displaying it, creating an opportunity for attackers to manipulate the address bar display. This behavior specifically affects the SSL attribute spoofing capability, allowing malicious actors to present false security indicators to users. The vulnerability operates under the principle that the browser should maintain consistent security state indicators regardless of how URLs are entered or modified within the interface.
The operational impact of this vulnerability is significant as it directly undermines user trust in the browser's security warnings and visual indicators. Attackers can leverage this flaw to create convincing phishing scenarios where the address bar displays misleading information about the security status of a website. This spoofing capability specifically targets the SSL certificate validation display, potentially making malicious sites appear legitimate to users who rely on visual security cues. The vulnerability requires user interaction to be exploited, as attackers must convince victims to paste malicious URLs into the address bar, but once triggered, it can effectively bypass the browser's built-in security mechanisms. This attack vector represents a classic case of user interface manipulation that exploits the gap between expected security behavior and actual implementation.
Security professionals should note that this vulnerability aligns with CWE-693, which addresses protection mechanism failures, and can be categorized under ATT&CK technique T1059 for user execution of malicious content. The flaw demonstrates poor input validation and insufficient navigation handling in web browsers, particularly when dealing with nonstandard protocols. Organizations should implement immediate mitigation strategies including prompt browser updates to version 41.0 or later, where the vulnerability has been addressed through enhanced URL validation and navigation handling. Additionally, user education regarding the risks of pasting URLs from untrusted sources and the importance of verifying SSL certificates manually can provide additional defense layers. The fix implemented by Mozilla involved strengthening the validation of URLs entered through paste operations and ensuring proper navigation handling regardless of scheme type, thereby preventing the spoofing conditions that previously enabled this attack.