CVE-2004-1012 in Cyrus IMAP Server
Summary
by MITRE
The argument parser of the PARTIAL command in Cyrus IMAP Server 2.2.6 and earlier allows remote authenticated users to execute arbitrary code via a certain command ("body[p") that is treated as a different command ("body.peek") and causes an index increment error that leads to an out-of-bounds memory corruption.
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Analysis
by VulDB Data Team • 06/05/2019
The vulnerability described in CVE-2004-1012 represents a critical buffer overflow flaw within the Cyrus IMAP Server's command parsing mechanism. This issue affects versions 2.2.6 and earlier, where the PARTIAL command implementation contains a flaw in how it processes specific argument patterns. The vulnerability arises from the server's inability to properly validate and handle malformed command arguments, creating a scenario where legitimate authenticated users can exploit this weakness to execute arbitrary code on the target system. The flaw specifically manifests when processing commands containing the pattern "body[p" which gets incorrectly interpreted as "body.peek" due to insufficient input validation. This misinterpretation creates a cascading effect where an index increment error occurs during command processing, ultimately resulting in out-of-bounds memory corruption that can be leveraged for remote code execution.
The technical implementation of this vulnerability stems from improper input sanitization within the IMAP server's argument parser component. When the server encounters the malformed command structure "body[p", it fails to properly validate the argument sequence and instead treats it as a legitimate "body.peek" command. This misclassification causes the parser to increment an index variable beyond its intended bounds, leading to memory corruption in the server's heap memory space. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though it manifests as heap corruption due to the specific parsing behavior. The flaw represents a classic case of improper input validation where the system assumes valid command structures without sufficient checks, creating an attack surface for authenticated remote adversaries.
The operational impact of this vulnerability extends beyond simple code execution capabilities, as it provides attackers with potential access to sensitive email data and system resources. An authenticated user with valid credentials can exploit this vulnerability to gain arbitrary code execution privileges on the IMAP server, potentially leading to complete system compromise. The attack vector requires only authentication to the IMAP service, making it particularly dangerous as it can be exploited by malicious insiders or compromised legitimate users. This vulnerability aligns with ATT&CK technique T1078 for valid accounts and T1059 for command and scripting interpreter, as it leverages legitimate authentication mechanisms to execute malicious code. The affected system could experience service disruption, data leakage, and potential lateral movement within the network if the compromised server serves as a gateway to other systems.
Mitigation strategies for CVE-2004-1012 should focus on immediate version upgrades to Cyrus IMAP Server 2.2.7 or later, which contain the necessary patches to address the argument parsing flaw. System administrators should implement strict access controls and monitor IMAP authentication logs for suspicious activities that might indicate exploitation attempts. Network segmentation and firewall rules should restrict access to IMAP services to trusted networks only, reducing the attack surface. Additionally, implementing intrusion detection systems that can identify malformed IMAP command sequences can help detect exploitation attempts. The vulnerability highlights the importance of robust input validation and proper error handling in server applications, particularly those handling user-provided data. Organizations should also consider implementing application-level firewalls and regular security assessments to identify similar parsing vulnerabilities in other server applications. This vulnerability serves as a reminder of the critical importance of maintaining up-to-date software versions and implementing comprehensive security controls around email infrastructure components.