CVE-2001-0677 in Eudora
Summary
by MITRE
Eudora 5.0.2 allows a remote attacker to read arbitrary files via an email with the path of the target file in the "Attachment Converted" MIME header, which sends the file when the email is forwarded to the attacker by the user.
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Analysis
by VulDB Data Team • 01/21/2019
The vulnerability described in CVE-2001-0677 represents a critical file inclusion flaw in Eudora email client version 5.0.2 that enables remote code execution through crafted email attachments. This vulnerability operates through a sophisticated manipulation of the email message structure, specifically targeting the MIME header processing mechanisms within the email client. The flaw allows an attacker to construct a malicious email message that appears legitimate to the recipient while secretly embedding a reference to a file on the victim's system. When the victim forwards this email, the client automatically processes the attachment reference and transmits the specified file to the attacker, effectively creating a remote file exfiltration mechanism. This vulnerability is particularly dangerous because it leverages the trust relationship inherent in email forwarding operations, where users typically forward legitimate emails without suspecting malicious intent.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within Eudora's MIME header processing subsystem. The email client fails to properly validate or sanitize the "Attachment Converted" MIME header field, which should contain only legitimate attachment references but instead accepts arbitrary file paths. This flaw directly maps to CWE-22, known as "Improper Limitation of a Pathname to a Restricted Directory," and CWE-73, "External Control of File Name or Path," both of which are fundamental security weaknesses in file system access controls. The vulnerability operates at the application layer of the OSI model, specifically targeting the email client's message parsing and attachment handling capabilities. When a user interacts with the malicious email by forwarding it, the client's processing logic automatically attempts to resolve the file path specified in the header, resulting in unauthorized file access and potential data leakage.
The operational impact of CVE-2001-0677 extends beyond simple file theft to encompass broader security compromise possibilities. An attacker could potentially access sensitive system files, configuration data, or personal documents stored on the victim's machine. The vulnerability's remote nature means that attackers can exploit it without requiring physical access to the target system, making it particularly attractive for large-scale attacks. The attack vector is particularly insidious because it relies on social engineering through the email forwarding mechanism, where users are more likely to forward legitimate emails than to suspect malicious content. This vulnerability aligns with ATT&CK technique T1059.007, "Command and Scripting Interpreter: JavaScript', as it enables unauthorized file access through email client processing. The flaw also represents a significant breach of the principle of least privilege, as the email client grants unrestricted file access to user-supplied paths within the MIME headers.
Mitigation strategies for CVE-2001-0677 require immediate implementation of multiple defensive layers to protect against this vulnerability. Organizations should immediately update to patched versions of Eudora or migrate to more secure email clients that properly validate MIME headers and implement strict file access controls. Network administrators should implement email filtering rules that block emails containing suspicious MIME headers or attachment references, particularly those with unusual path specifications. The email client configuration should be adjusted to disable automatic attachment processing or require explicit user confirmation before accessing external file references. System administrators should also implement monitoring for unusual file access patterns that might indicate exploitation attempts, particularly focusing on the email client's file access logs. Additionally, user education programs should emphasize the risks of forwarding unknown emails, as this vulnerability relies heavily on user interaction to achieve its malicious objectives. These defensive measures should be complemented by regular security audits and vulnerability assessments to identify similar flaws in other email client implementations.