CVE-2005-1523 in Mailutils
Summary
by MITRE
Format string vulnerability in imap4d server in GNU Mailutils 0.5 and 0.6, and other versions before 0.6.90, allows remote attackers to execute arbitrary code via format string specifiers in the command tag for IMAP commands.
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Analysis
by VulDB Data Team • 01/03/2025
The vulnerability described in CVE-2005-1523 represents a critical format string vulnerability within the imap4d server component of GNU Mailutils versions 0.5 and 0.6, as well as other releases prior to 0.6.90. This flaw exists in the IMAP server implementation that processes command tags from client connections, creating a pathway for remote code execution through maliciously crafted format string specifiers. The vulnerability specifically affects the server's handling of IMAP commands where the command tag parameter is not properly sanitized before being processed through printf-style functions. This issue falls under the Common Weakness Enumeration category CWE-134, which specifically addresses the use of format strings with user-supplied data without proper validation or sanitization.
The technical exploitation of this vulnerability occurs when a remote attacker sends specially crafted IMAP commands containing format string specifiers in the command tag field. The imap4d server processes these tags without adequate input validation, allowing attackers to manipulate the printf function calls that handle the command tag data. This manipulation can lead to memory corruption, stack smashing, or controlled code execution within the server process. The vulnerability's impact extends beyond simple privilege escalation as it allows attackers to execute arbitrary code with the privileges of the imap4d server process, which typically runs with system-level permissions. The attack vector requires network access to the IMAP service and does not require authentication, making it particularly dangerous for systems with exposed mail services.
The operational impact of CVE-2005-1523 is severe for organizations running GNU Mailutils servers, as it creates a direct path for remote compromise of mail infrastructure. Attackers can leverage this vulnerability to gain full control over the affected server, potentially leading to data exfiltration, service disruption, or use as a pivot point for further attacks within the network. The vulnerability affects not only the immediate server but also any systems that rely on the compromised mail infrastructure for communication or authentication. Organizations with exposed IMAP services face significant risk, particularly those running older versions of GNU Mailutils that have not received the security patch. The vulnerability demonstrates the importance of proper input validation and secure coding practices, especially when dealing with user-supplied data in server applications. According to ATT&CK framework, this vulnerability maps to T1059.007 for remote code execution and T1046 for network service discovery, as attackers can use this flaw to establish persistent access and further explore network resources. The remediation strategy involves upgrading to GNU Mailutils version 0.6.90 or later, which contains the necessary patches to prevent format string exploitation. System administrators should also implement network segmentation, disable unnecessary IMAP services, and monitor for suspicious connection patterns that may indicate exploitation attempts. The vulnerability underscores the critical need for regular security updates and proper input sanitization in network services to prevent similar issues in the future.