CVE-2004-1013 in Cyrus IMAP Server
Summary
by MITRE
The argument parser of the FETCH command in Cyrus IMAP Server 2.2.x through 2.2.8 allows remote authenticated users to execute arbitrary code via certain commands such as (1) "body[p", (2) "binary[p", or (3) "binary[p") that cause an index increment error that leads to an out-of-bounds memory corruption.
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Analysis
by VulDB Data Team • 05/31/2019
The vulnerability identified as CVE-2004-1013 represents a critical buffer overflow condition within the Cyrus IMAP Server's FETCH command argument parsing functionality. This flaw exists in versions 2.2.x through 2.2.8 of the server software, affecting systems that rely on this widely deployed IMAP implementation for email services. The vulnerability specifically targets the argument parser component that processes FETCH commands, which are fundamental operations used by email clients to retrieve message data from IMAP servers. The security implications are severe as this vulnerability can be exploited by authenticated remote attackers who possess valid credentials to access the IMAP service, making it particularly dangerous in environments where user authentication is the primary security control.
The technical mechanism behind this vulnerability involves a specific class of malformed argument sequences that trigger an index increment error during the parsing process. When processing commands such as "body[p", "binary[p", or "binary[p") the parser fails to properly validate input boundaries, leading to an out-of-bounds memory access condition. This particular flaw falls under the CWE-121 CWE-125 and CWE-787 categories, which respectively address stack-based buffer overflow conditions and out-of-bounds read/write operations. The error occurs when the parser attempts to increment an index variable without proper bounds checking, causing memory corruption that can be leveraged to execute arbitrary code. The vulnerability is classified as a heap-based buffer overflow in the context of memory corruption attacks, where the attacker can manipulate the parser's internal state to overwrite adjacent memory locations with malicious data.
The operational impact of this vulnerability extends beyond simple code execution to potentially compromise entire email infrastructure systems. Remote authenticated attackers who can establish legitimate IMAP sessions can exploit this flaw to gain unauthorized code execution privileges on the affected server. This capability allows attackers to escalate their privileges, potentially leading to full system compromise, data exfiltration, or service disruption. The vulnerability is particularly concerning because it requires only authenticated access, meaning that an attacker who has obtained legitimate user credentials can exploit this flaw without requiring additional attack vectors or elevated privileges. The attack surface is broad as virtually any system running affected versions of Cyrus IMAP Server could be compromised, including enterprise email servers, webmail platforms, and any applications relying on IMAP for email processing.
Mitigation strategies for this vulnerability should include immediate patching of all affected Cyrus IMAP Server installations to versions that contain the necessary fixes for the argument parsing logic. Organizations should implement network segmentation and access controls to limit exposure of IMAP services to trusted networks and users. Monitoring for suspicious authentication patterns and unusual FETCH command sequences can help detect potential exploitation attempts. The implementation of intrusion detection systems that can identify malformed IMAP commands and memory corruption patterns provides additional defensive layers. Security teams should also conduct comprehensive vulnerability assessments to identify all systems running affected software versions and ensure proper patch management procedures are in place. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and command execution through legitimate system processes, making it a significant concern for organizations implementing security controls that rely on proper authentication mechanisms.