CVE-2004-2301 in Eudora
Summary
by MITRE
Eudora before 6.1.1 allows remote attackers to cause a denial of service (crash) via an e-mail with a long "To:" field, possibly due to a buffer overflow.
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Analysis
by VulDB Data Team • 03/25/2019
The vulnerability identified as CVE-2004-2301 represents a classic buffer overflow flaw affecting the Eudora email client version 6.1.0 and earlier. This issue specifically manifests when the application processes email messages containing excessively long "To:" field values, leading to system instability and potential application crashes. The vulnerability stems from inadequate input validation mechanisms within the email parsing routine, where the software fails to properly handle or limit the length of header fields before processing them. Such buffer overflow conditions occur when the application attempts to write data beyond the allocated memory boundaries for the "To:" field buffer, causing memory corruption that ultimately results in application termination. The flaw demonstrates a fundamental weakness in memory management practices and input sanitization within the email client's processing pipeline.
The technical exploitation of this vulnerability requires remote attackers to craft malicious email messages containing abnormally long "To:" field entries, typically exceeding the buffer capacity allocated by the Eudora application. When the vulnerable client processes such messages, the buffer overflow condition triggers memory corruption that causes the application to crash or become unresponsive. This denial of service condition affects the availability of the email client service, preventing legitimate users from accessing their email functionality. The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a specific instance of improper input validation that allows attackers to manipulate application memory structures through crafted input data. The attack vector is particularly concerning as it requires no special privileges or authentication, making it accessible to any remote attacker who can deliver email to the target system.
From an operational perspective, this vulnerability creates significant risk for organizations relying on Eudora email clients, particularly in environments where email systems serve as critical communication infrastructure. The denial of service impact extends beyond individual user inconvenience to potentially disrupt business operations, especially in scenarios where email remains the primary means of internal or external communication. The vulnerability's remote nature means that attackers can exploit it without physical access to the target system, making it particularly dangerous in networked environments. Security professionals should note that this flaw exemplifies the importance of robust input validation and memory safety practices in email processing applications, as demonstrated by the ATT&CK technique T1499.004 for network denial of service attacks. Organizations with affected systems face potential reputational damage and operational disruption, as users experience intermittent service interruptions while the application crashes and requires manual restart.
Mitigation strategies for CVE-2004-2301 focus primarily on applying the vendor-provided patch that updates Eudora to version 6.1.1 or later, which includes proper input validation and buffer size limitations for header fields. System administrators should implement email filtering solutions that can detect and block messages containing suspiciously long header fields as an additional defensive measure. Network security controls can be configured to monitor for unusual email processing patterns that might indicate exploitation attempts. Organizations should also consider implementing email client hardening practices, including disabling unnecessary features and restricting email client capabilities where possible. The vulnerability underscores the importance of maintaining up-to-date software versions and demonstrates how seemingly simple input validation issues can lead to significant availability problems. Regular security assessments of email infrastructure and comprehensive patch management procedures should be implemented to prevent similar vulnerabilities from affecting other email client applications. Additionally, user education regarding suspicious email content and the potential for exploitation through crafted email messages can provide an additional layer of defense against such attacks.