CVE-2005-0585 in Firefox
Summary
by MITRE
Firefox before 1.0.1 and Mozilla before 1.7.6 truncates long sub-domains or paths for display, which may allow remote malicious web sites to spoof legitimate sites and facilitate phishing attacks.
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Analysis
by VulDB Data Team • 07/01/2021
The vulnerability described in CVE-2005-0585 represents a critical security flaw in the web browser implementations of both Firefox and Mozilla browsers prior to their respective version 1.0.1 and 1.7.6 releases. This issue stems from the browsers' handling of URL display formatting where excessively long sub-domains or paths are artificially truncated for presentation purposes. The technical implementation of this truncation mechanism creates a window of opportunity for malicious actors to exploit the visual representation of web addresses, as the truncated display may obscure the true identity of the originating website. This behavior fundamentally undermines the user's ability to accurately verify website authenticity through visual inspection of the address bar.
The core technical flaw manifests in how browsers process and render Uniform Resource Locators when they exceed predetermined length thresholds. When a domain or path exceeds the maximum displayable length, the browser applies truncation logic that typically removes characters from the middle or end of the string, leaving only a portion of the complete URL visible to users. This truncation process, while intended to maintain usability and prevent display overflow, creates a security risk by allowing attackers to craft malicious URLs that appear legitimate when truncated. The vulnerability specifically targets the user interface presentation layer rather than the underlying URL parsing or validation mechanisms, making it particularly insidious as it exploits user trust in visual verification methods.
The operational impact of this vulnerability extends beyond simple visual deception to enable sophisticated phishing attacks that can bypass user security awareness. Attackers can register domain names with extremely long sub-domains or paths that, when truncated, closely resemble legitimate websites such as banks, e-commerce platforms, or social media services. This manipulation of URL display creates a false sense of security for users who rely on visual inspection to validate website authenticity. The vulnerability is particularly dangerous because it operates at the user interface level where human judgment and trust play critical roles in security decisions, making it significantly more difficult to detect and prevent compared to traditional technical exploits.
This vulnerability aligns with CWE-601, which addresses URL Redirector Abuse, and demonstrates characteristics that map to several ATT&CK techniques including T1566.001 for Phishing and T1071.004 for Application Layer Protocol. The flaw essentially creates a condition where the browser's display mechanism can be manipulated to present misleading information, enabling attackers to conduct deception campaigns that exploit user cognitive biases and trust in familiar website appearances. Security professionals should note that this vulnerability highlights the importance of considering user interface design in security contexts, as visual presentation elements can become attack vectors when they do not accurately represent underlying security properties. Organizations should implement comprehensive security awareness training to help users recognize potential phishing attempts that exploit such display vulnerabilities, while browser vendors must ensure that display truncation mechanisms maintain security integrity and do not inadvertently facilitate deception attacks.
The remediation approach for CVE-2005-0585 required browser vendors to modify their URL display logic to prevent truncation of critical security information or to implement more sophisticated display mechanisms that maintain the integrity of website identification. Modern browsers have since addressed this issue through improved URL handling, enhanced display mechanisms, and more robust security indicators that make it significantly harder for attackers to exploit similar truncation vulnerabilities. The incident underscores the broader principle that security considerations must be integrated throughout the entire software development lifecycle, including user interface design, rather than being treated as an afterthought or purely technical concern.