CVE-2006-3486 in MySQL
Summary
by MITRE
** DISPUTED ** Off-by-one buffer overflow in the Instance_options::complete_initialization function in instance_options.cc in the Instance Manager in MySQL before 5.0.23 and 5.1 before 5.1.12 might allow local users to cause a denial of service (application crash) via unspecified vectors, which triggers the overflow when the convert_dirname function is called. NOTE: the vendor has disputed this issue via e-mail to CVE, saying that it is only exploitable when the user has access to the configuration file or the Instance Manager daemon. Due to intended functionality, this level of access would already allow the user to disrupt program operation, so this does not cross security boundaries and is not a vulnerability.
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Analysis
by VulDB Data Team • 08/07/2024
The vulnerability described in CVE-2006-3486 relates to an off-by-one buffer overflow condition within the MySQL Instance Manager's instance_options.cc file, specifically within the Instance_options::complete_initialization function. This flaw exists in MySQL versions prior to 5.0.23 and 5.1.12, representing a classic buffer management issue that could potentially lead to application instability. The vulnerability manifests when the convert_dirname function is invoked, creating a scenario where memory boundaries are exceeded due to improper buffer size calculations.
The technical implementation of this vulnerability stems from a fundamental error in memory allocation and boundary checking within the Instance Manager component of MySQL. An off-by-one error occurs when a program writes one byte beyond the allocated buffer space, typically due to incorrect loop conditions or boundary calculations. In this case, the flaw is triggered during the initialization phase of instance options, where the convert_dirname function processes directory path information. The buffer overflow condition creates a situation where adjacent memory locations are overwritten, potentially corrupting program state and leading to unpredictable behavior.
From an operational perspective, this vulnerability presents a local denial of service risk that could cause the MySQL Instance Manager daemon to crash and terminate unexpectedly. While the vendor has disputed this classification as a security vulnerability, the implications remain significant for system administrators who must consider the broader threat landscape. The denial of service condition could impact database availability and require manual intervention to restore normal operations, particularly in environments where the Instance Manager is critical for database instance management.
The disputed nature of this vulnerability stems from the vendor's assertion that exploitation requires pre-existing access to either the configuration file or the Instance Manager daemon, which would already provide sufficient privileges to disrupt program operations through legitimate means. This aligns with security principle that vulnerabilities requiring elevated privileges or existing access do not typically qualify as security vulnerabilities under standard threat models. However, the potential for privilege escalation or exploitation through other attack vectors cannot be entirely dismissed, particularly in complex deployment scenarios.
According to CWE classification, this vulnerability would be categorized as CWE-121, which addresses stack-based buffer overflow conditions, though the specific nature of the off-by-one error suggests a more nuanced analysis under CWE-122 for heap-based buffer overflows. The ATT&CK framework would classify this under T1489, which covers denial of service attacks, though the specific technique would be considered a privilege escalation vector rather than a direct network-based attack. The vendor's assessment that this does not cross security boundaries aligns with the principle that legitimate access to configuration files or daemon processes already provides sufficient capability to cause disruption, making this a functional rather than a security vulnerability.
The recommended mitigation strategy focuses on ensuring proper version control and applying the vendor patches released in MySQL 5.0.23 and 5.1.12, which address the buffer overflow condition in the instance_options.cc file. System administrators should also implement proper access controls and privilege separation to minimize potential impact from any local user with access to configuration files or daemon processes. Regular security assessments and monitoring of Instance Manager operations can help detect anomalous behavior that might indicate exploitation attempts, even if the vulnerability itself is not considered a security risk under standard threat models.