CVE-2001-0365 in Eudora
Summary
by MITRE
Eudora before 5.1 allows a remote attacker to execute arbitrary code, when the Use Microsoft Viewer and allow executables in HTML content options are enabled, via an HTML email message containing Javascript, with ActiveX controls and malicious code within IMG tags.
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Analysis
by VulDB Data Team • 05/03/2025
The vulnerability described in CVE-2001-0365 represents a critical security flaw in Eudora email client versions prior to 5.1 that demonstrates the dangers of improper input validation and unsafe handling of web content within email applications. This vulnerability specifically targets the email client's HTML rendering engine and illustrates how seemingly benign email content can be exploited to deliver malicious payloads. The flaw occurs when users have enabled two specific configuration options: "Use Microsoft Viewer" and "allow executables in HTML content." These settings create a dangerous combination that allows the email client to process and execute potentially malicious code directly from HTML email messages without proper sandboxing or security controls.
The technical exploitation mechanism relies on the manipulation of HTML email content through IMG tags that contain ActiveX controls and embedded JavaScript code. This approach leverages the trust relationship between the email client and its Microsoft Viewer component, which is designed to handle various document formats including HTML content. When an attacker crafts an HTML email message containing malicious code within IMG tags, the email client's parser processes these elements and executes the embedded ActiveX controls as if they were legitimate components. The vulnerability falls under the category of cross-site scripting and code injection attacks, specifically aligning with CWE-94 which describes "Improper Control of Generation of Code ('Code Injection')" and CWE-74 which covers "Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')". The attack vector exploits the client-side rendering capabilities of the email application to execute arbitrary code on the victim's system.
The operational impact of this vulnerability is severe and far-reaching, as it allows remote attackers to gain complete control over affected systems without requiring any user interaction beyond reading the malicious email. Once executed, the malicious code can perform various harmful actions including but not limited to downloading additional malware, establishing backdoors, modifying system files, stealing sensitive information, or creating persistent access to the compromised system. This vulnerability effectively transforms any user who reads the malicious email into an unwitting participant in a security breach, making it particularly dangerous in corporate environments where email is a primary communication channel. The exploitability of this vulnerability is enhanced by the fact that it requires minimal user interaction and can be delivered through standard email channels, making it an attractive target for attackers seeking widespread compromise.
The security implications extend beyond immediate system compromise to include potential lateral movement within networks and persistent threat capabilities. Attackers can leverage this vulnerability to establish footholds in organizations, potentially leading to data breaches, intellectual property theft, or disruption of business operations. The vulnerability demonstrates the importance of secure coding practices and proper input validation in client-side applications, particularly those that process untrusted content from external sources. Organizations should implement comprehensive security measures including email filtering, user education about dangerous email content, and regular security updates to protect against similar vulnerabilities. Mitigation strategies should focus on disabling unsafe HTML content processing features, implementing strict email security policies, and ensuring that email clients are regularly updated to versions that address known vulnerabilities. This vulnerability also highlights the need for defense-in-depth strategies that include network monitoring, endpoint protection, and incident response capabilities to detect and respond to exploitation attempts. The attack pattern aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript" and T1203 for "Exploitation for Client Execution" which emphasizes the importance of protecting client applications from malicious content execution.