CVE-2017-3639 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: DML). Supported versions that are affected are 5.7.18 and earlier. Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.0 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
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Analysis
by VulDB Data Team • 01/04/2021
The vulnerability identified as CVE-2017-3639 resides within Oracle MySQL Server's DML (Data Manipulation Language) subsystem, specifically affecting versions 5.7.18 and earlier. This represents a critical availability threat that stems from improper handling of certain database operations, creating a pathway for malicious actors to disrupt database services. The vulnerability operates at the server level, meaning it impacts the core functionality of the MySQL database engine rather than client-side components or network protocols. The affected MySQL Server component processes data manipulation commands including insert, update, and delete operations, making it particularly concerning for database environments where these operations are frequent and critical to business operations. The vulnerability's classification as easily exploitable indicates that minimal technical expertise is required to craft successful attacks against vulnerable systems.
The technical flaw manifests through a specific condition in the server's processing of certain DML operations that leads to memory corruption or resource exhaustion. When an attacker with high privileges executes carefully crafted database commands, the server's internal state becomes corrupted in such a way that it either hangs indefinitely or crashes repeatedly. This behavior creates a denial of service condition that can completely disable database access for legitimate users while potentially requiring system restarts to restore normal operations. The vulnerability's impact extends beyond simple service interruption as it can cause cascading failures in applications that depend on the database for their functionality. The specific nature of the flaw involves the server's inability to properly handle resource management during complex data manipulation sequences, leading to unpredictable behavior that manifests as system instability. The attack vector requires network access and high privilege levels, suggesting that the vulnerability is more likely to be exploited by insiders or attackers who have already gained significant access to the system.
The operational impact of this vulnerability can be severe for organizations relying on MySQL databases, particularly in mission-critical environments where database availability is essential for business operations. A successful exploitation can result in complete database service outages that may last from minutes to hours, depending on the recovery mechanisms in place. The availability impact is rated as high with a CVSS score of 4.9, indicating that the vulnerability can cause significant disruption to database services and potentially affect downstream applications and business processes. Organizations may experience data access delays, application failures, and increased operational overhead as they respond to service interruptions. The repeated crash behavior suggests that even a single exploitation attempt could render the database service unusable until manual intervention occurs, potentially requiring database restarts or system reboots to restore functionality. This vulnerability particularly affects environments where database administrators have high-privilege accounts, as the attack requires elevated access levels to execute the malicious commands effectively.
Mitigation strategies for CVE-2017-3639 should prioritize immediate patching of affected MySQL Server installations to version 5.7.19 or later, which contains the necessary fixes for this vulnerability. Organizations should implement network segmentation and access controls to limit the number of users with high-privilege database accounts, reducing the potential attack surface for this vulnerability. The principle of least privilege should be enforced by ensuring that database users have only the minimum necessary permissions to perform their required tasks, thereby limiting the potential impact of privilege-based attacks. Network monitoring should be enhanced to detect unusual patterns of database access that might indicate exploitation attempts, including monitoring for repeated connection attempts or unusual query patterns. Additionally, implementing database activity monitoring and alerting systems can help identify when the vulnerability is being exploited, providing early detection capabilities that can reduce the impact of successful attacks. Regular vulnerability assessments and penetration testing should be conducted to identify and remediate similar vulnerabilities in the database infrastructure. The vulnerability aligns with CWE-121, which covers stack-based buffer overflow conditions, and relates to ATT&CK technique T1499.004 for network denial of service, highlighting the broader implications for database security and availability. Organizations should also consider implementing redundant database systems and backup procedures to ensure business continuity in case of successful exploitation attempts.