CVE-2004-0526 in Internet Explorer
Summary
by MITRE
Unknown versions of Internet Explorer and Outlook allow remote attackers to spoof a legitimate URL in the status bar via A HREF tags with modified "alt" values that point to the legitimate site, combined with an image map whose href points to the malicious site, which facilitates a "phishing" attack.
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Analysis
by VulDB Data Team • 09/14/2025
This vulnerability represents a sophisticated phishing attack vector that exploits the trust relationship between web browsers and users through manipulated hyperlink structures. The flaw exists in older versions of internet explorer and outlook clients where the status bar display mechanism fails to properly validate the authenticity of URL references, creating a scenario where attackers can craft deceptive web pages that appear legitimate to users. The vulnerability specifically targets the browser's URL display functionality by leveraging the interaction between html href attributes and alt text values, allowing malicious actors to present misleading information to unsuspecting users.
The technical implementation of this attack involves crafting html elements where the alt attribute of an anchor tag contains a legitimate URL while the image map associated with that tag points to a malicious destination. This creates a situation where users see a trusted website address in their browser status bar while the actual navigation occurs to a fraudulent site. The vulnerability operates at the application layer of the osi model, specifically within the presentation layer where html rendering and user interface elements are processed. This attack pattern demonstrates a classic case of user interface deception that bypasses traditional security mechanisms by exploiting the implicit trust users place in browser status bar displays.
The operational impact of this vulnerability extends beyond simple phishing attempts to include potential credential theft, financial fraud, and data exfiltration. Users who trust the displayed URL information may unknowingly submit sensitive information to malicious sites, believing they are interacting with legitimate services. This attack vector is particularly dangerous because it operates at the user interaction level where security controls are often weakest, relying on human judgment rather than technical safeguards. The vulnerability affects both desktop browsers and email clients, expanding the attack surface significantly since users may encounter these deceptive links in both web browsing and email contexts.
Security professionals should recognize this vulnerability as a manifestation of CWE-601 URL Redirection to Untrusted Site, which specifically addresses the risk of redirecting users to malicious destinations through seemingly legitimate links. The attack pattern aligns with several tactics described in the mitre ATT&CK framework under the initial access and credential access domains, particularly leveraging social engineering techniques to bypass traditional security controls. Organizations should implement comprehensive browser security policies, including disabling or restricting the use of image maps in critical applications, and educating users about the risks of relying solely on status bar URL displays for security validation.
Mitigation strategies must address both the immediate technical vulnerability and the broader security awareness implications. System administrators should deploy browser security updates and patches, implement content filtering solutions, and configure email clients to sanitize html content. The vulnerability highlights the importance of defense in depth approaches where multiple security controls work together to protect against deception attacks. Regular security assessments should include testing for similar URL manipulation vulnerabilities, and user training programs should emphasize the importance of verifying website authenticity through multiple means rather than relying on single indicators like status bar displays. Organizations should also consider implementing browser extensions or security tooling that can detect and warn users about suspicious URL patterns in web content.