CVE-2003-0881 in Mac OS X
Summary
by MITRE
Mail in Mac OS X before 10.3, when configured to use MD5 Challenge Response, uses plaintext authentication if the CRAM-MD5 hashed login fails, which could allow remote attackers to gain privileges by sniffing the password.
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Analysis
by VulDB Data Team • 05/04/2019
The vulnerability described in CVE-2003-0881 represents a critical authentication flaw in the Mail application of Mac OS X versions prior to 10.3. This issue manifests when the email client is configured to utilize MD5 Challenge Response authentication mechanisms, creating a dangerous fallback behavior that undermines security protocols. The vulnerability stems from the application's improper handling of authentication failures, specifically when CRAM-MD5 authentication fails to establish a secure connection. When the initial MD5 Challenge Response authentication attempt encounters an error or fails for any reason, the system automatically reverts to plaintext authentication, exposing user credentials in an unencrypted format. This design flaw creates a significant attack surface that malicious actors can exploit through network sniffing techniques to capture sensitive authentication data.
The technical implementation of this vulnerability aligns with CWE-312, which addresses the exposure of sensitive information through cleartext storage or transmission. The flaw occurs at the protocol level where the Mail application fails to maintain consistent security posture during authentication failures, creating a scenario where the system's security controls are bypassed. When an attacker intercepts network traffic between the Mail client and the mail server, they can capture the plaintext password transmitted during the fallback authentication process. This vulnerability particularly affects environments where network traffic is not properly secured through additional layers such as TLS encryption, making the attack surface even more expansive. The authentication mechanism's failure to properly handle error conditions demonstrates a lack of robust security design principles that should be implemented in all authentication systems.
The operational impact of CVE-2003-0881 extends beyond simple credential theft, potentially enabling attackers to gain unauthorized access to email accounts and subsequently exploit them for further malicious activities. This vulnerability can be leveraged as part of broader attack campaigns where stolen credentials are used for phishing attempts, spam distribution, or as stepping stones for more sophisticated attacks within a network. The attack vector requires only network monitoring capabilities, making it particularly dangerous in shared network environments or public Wi-Fi networks where traffic interception is relatively straightforward. According to ATT&CK framework, this vulnerability maps to T1110.003, which covers credential access through network sniffing, and T1078.004, which addresses legitimate credentials used for unauthorized access. Organizations using affected Mac OS X versions face significant risk of account compromise, especially in environments where email systems handle sensitive corporate or personal data.
Mitigation strategies for this vulnerability primarily involve upgrading to Mac OS X 10.3 or later versions where the authentication handling has been corrected to prevent plaintext fallback. System administrators should implement mandatory TLS encryption for all email communications to prevent credential interception even if the underlying authentication mechanism fails. Network segmentation and monitoring solutions can help detect unusual authentication patterns or potential credential sniffing activities. Additionally, organizations should enforce strong authentication policies that require multi-factor authentication and disable plaintext authentication mechanisms wherever possible. The vulnerability highlights the importance of proper error handling in security-sensitive applications and demonstrates how seemingly minor implementation flaws can create significant security risks. Security teams should conduct regular vulnerability assessments to identify similar authentication fallback mechanisms in other applications and ensure that all systems maintain consistent security postures during authentication failures.