CVE-2004-1067 in Cyrus IMAP Server
Summary
by MITRE
Off-by-one error in the mysasl_canon_user function in Cyrus IMAP Server 2.2.9 and earlier leads to a buffer overflow, which may allow remote attackers to execute arbitrary code via the username.
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Analysis
by VulDB Data Team • 05/27/2019
The vulnerability described in CVE-2004-1067 represents a critical buffer overflow flaw within the Cyrus IMAP Server software that has significant implications for email security infrastructure. This issue affects versions 2.2.9 and earlier of the Cyrus IMAP server implementation, which was widely deployed in enterprise and organizational email systems during that time period. The vulnerability stems from an off-by-one error in the mysasl_canon_user function, a component responsible for canonicalizing user names during authentication processes. This type of error occurs when a program manipulates array indices or string lengths incorrectly, leading to memory access violations that can be exploited by malicious actors.
The technical nature of this vulnerability places it squarely within the category of buffer overflow conditions classified under CWE-121, which specifically addresses stack-based buffer overflow scenarios. When a remote attacker crafts a specially formatted username that exceeds the allocated buffer space by exactly one byte, the overflow occurs in the mysasl_canon_user function. This particular function processes user authentication requests and performs name canonicalization to ensure proper user identification within the IMAP server environment. The off-by-one error means that the program does not properly check bounds before writing data to memory locations adjacent to the intended buffer, creating a predictable memory corruption scenario.
The operational impact of this vulnerability extends far beyond simple denial of service conditions, as it creates a potential code execution vector that could allow attackers to gain unauthorized access to email servers. When successfully exploited, the buffer overflow could enable remote code execution with the privileges of the Cyrus IMAP server process, potentially leading to complete system compromise. This scenario aligns with ATT&CK technique T1190, which covers exploitation of remote services through buffer overflow vulnerabilities. The implications for email security are particularly severe since IMAP servers often contain sensitive user data, including personal communications, business correspondence, and potentially confidential organizational information.
Organizations running affected versions of the Cyrus IMAP server face substantial risk from this vulnerability, as it represents a well-known exploitation pattern that would likely be leveraged by threat actors targeting email infrastructure. The vulnerability's remote exploitability means that attackers do not require local access or credentials to attempt exploitation, making it particularly dangerous in networked environments. Security professionals should recognize that this vulnerability was part of a broader class of buffer overflow issues that plagued many network services during the early 2000s, highlighting the importance of proper input validation and memory management in server applications. The recommended mitigation involves immediate upgrade to Cyrus IMAP Server versions 2.2.10 or later, where the buffer overflow has been corrected through proper bounds checking and input validation measures. Additionally, organizations should implement network segmentation, access controls, and monitoring to detect potential exploitation attempts while applying the necessary patches to eliminate the vulnerability from their systems.