CVE-2005-0586 in Firefox
Summary
by MITRE
Firefox before 1.0.1 and Mozilla before 1.7.6 allows remote malicious web sites to spoof the extensions of files to download via the Content-Disposition header, which could be used to trick users into downloading dangerous content.
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Analysis
by VulDB Data Team • 05/31/2019
The vulnerability described in CVE-2005-0586 represents a significant security flaw in web browser download handling mechanisms that affected Firefox versions prior to 1.0.1 and Mozilla versions before 1.7.6. This issue stems from the improper processing of the Content-Disposition HTTP header, which is designed to instruct web browsers on how to handle file downloads. The flaw allows malicious web servers to manipulate this header to display misleading file extensions to users while actually serving malicious content, creating a deceptive environment where users might be tricked into executing dangerous files.
The technical implementation of this vulnerability resides in the browser's interpretation of the Content-Disposition header's filename parameter. When a web server sends a response with a Content-Disposition header containing a filename attribute, the browser should properly validate and display this information to users. However, the affected versions of Firefox and Mozilla failed to adequately sanitize or verify the filename parameter, allowing attackers to inject misleading extensions that would appear in the download dialog but do not reflect the actual file type being served. This creates a scenario where a user might see a .pdf file being downloaded but actually receive a .exe or .bat file containing malicious code.
The operational impact of this vulnerability extends beyond simple deception, as it enables sophisticated social engineering attacks that leverage user trust in file extensions. Attackers can exploit this weakness by hosting malicious content on legitimate-looking websites and using the Content-Disposition header to present benign extensions such as .pdf, .doc, or .zip while actually delivering executable files. This manipulation directly violates user expectations and security assumptions, potentially leading to successful compromise of user systems through drive-by downloads or phishing campaigns. The vulnerability specifically aligns with CWE-115, which addresses the improper handling of data representation, and represents a clear violation of the principle of least privilege in user interface design.
The security implications of this flaw are particularly concerning given the widespread use of these browsers at the time of discovery. Users operating vulnerable versions were susceptible to attacks that could bypass traditional security measures such as antivirus scanning, as the deception occurred at the browser level before any content inspection could take place. This vulnerability also demonstrates the importance of proper input validation and header parsing in web applications, as it shows how seemingly benign HTTP headers can be weaponized for malicious purposes. Organizations using these vulnerable browsers faced increased risk of malware infections and potential data breaches, particularly in environments where users might encounter untrusted web content.
Mitigation strategies for this vulnerability required immediate browser updates to properly parse and validate Content-Disposition headers. Users should have upgraded to Firefox 1.0.1 or Mozilla 1.7.6, which included fixes that properly handled filename parameters in Content-Disposition headers. System administrators needed to implement additional security measures such as network-level content filtering and user education about download behaviors. The fix implemented by the browser vendors typically involved stricter parsing of the Content-Disposition header and enhanced validation of filename parameters to prevent malicious manipulation. This vulnerability also highlighted the need for comprehensive security testing of HTTP header handling and the importance of maintaining current browser versions to protect against known security flaws. The remediation process demonstrated the critical importance of timely security updates and proper vulnerability management practices in enterprise security environments.