CVE-2007-4357 in Firefox
Summary
by MITRE
Mozilla Firefox 2.0.0.6 and earlier allows remote attackers to spoof the contents of the status bar via a link to a data: URI containing an encoded URL. NOTE: the severity of this issue has been disputed by a reliable third party, since the intended functionality of the status bar allows it to be modified.
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Analysis
by VulDB Data Team • 09/06/2018
The vulnerability described in CVE-2007-4357 represents a security flaw in Mozilla Firefox versions 2.0.0.6 and earlier that enables remote attackers to manipulate the browser's status bar display through malicious data URIs. This issue falls under the category of user interface spoofing attacks where attackers can deceive users by displaying false information in the browser's status bar area. The vulnerability specifically exploits the way Firefox handles data: URIs, which are designed to embed small amounts of data directly into web pages. When a user clicks on a link containing a specially crafted data: URI with encoded URL content, the browser's status bar can be manipulated to show misleading information that appears to be legitimate but is actually generated by the malicious actor.
The technical implementation of this vulnerability involves the manipulation of data: URIs within web content to trigger specific behavior in the Firefox browser's status bar rendering mechanism. Data URIs are base64 encoded data streams that can be embedded directly into HTML documents, and when combined with encoded URLs, they can exploit how Firefox processes these elements in the status bar context. The flaw allows attackers to present false information such as fake download links, phishing URLs, or misleading status messages that users might trust implicitly. This type of attack targets the user's perception of security and can be particularly dangerous when combined with other social engineering techniques. The vulnerability demonstrates a weakness in Firefox's input validation and output rendering processes, specifically in how it handles data: URI content within the context of status bar updates.
The operational impact of this vulnerability extends beyond simple visual deception as it can be leveraged to create more sophisticated phishing attacks or to mislead users about the actual destination of their navigation. Users may be tricked into believing they are visiting legitimate websites when they are actually being directed to malicious content, or they might be misled about the security status of their current page. The intended functionality of the status bar, which was designed to allow legitimate modification by web pages, was inadvertently exploited to enable malicious behavior. This vulnerability operates in the context of web browser security and can be classified under CWE-693, which deals with protection mechanism failures, specifically in the area of user interface manipulation. The attack vector represents a form of user interface deception that can be particularly effective in social engineering campaigns where trust in browser indicators is crucial.
The disputed severity of this vulnerability stems from the fact that the status bar functionality was originally intended to be modifiable by web pages, making the behavior somewhat expected within the browser's design framework. However, this does not diminish the security implications of the flaw, as it still enables attackers to manipulate user perception in potentially harmful ways. The vulnerability demonstrates the importance of understanding the intended security boundaries of browser components and how legitimate features can be subverted for malicious purposes. From an ATT&CK perspective, this vulnerability relates to techniques involving user interface deception and credential access through social engineering. The issue highlights the need for comprehensive security testing that considers not just the functional aspects of browser components but also their potential for abuse in user interaction contexts. Organizations should implement browser security policies that account for such vulnerabilities and consider the broader implications of allowing web content to modify browser interface elements. The vulnerability underscores the ongoing challenge of balancing legitimate web functionality with security requirements in browser design and implementation.