CVE-2017-3648 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: Charsets). Supported versions that are affected are 5.5.56 and earlier, 5.6.36 and earlier and 5.7.18 and earlier. Difficult to exploit 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 4.4 (Availability impacts). CVSS Vector: (CVSS:3.0/AV:N/AC:H/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-2017-3648 resides within the MySQL Server component, specifically within the Server: Charsets subcomponent of Oracle MySQL database software. This issue affects multiple version ranges including 5.5.56 and earlier, 5.6.36 and earlier, and 5.7.18 and earlier releases, representing a significant portion of the MySQL ecosystem that was prevalent during the affected period. The vulnerability classification as a difficulty to exploit indicates that while the attack vector is not trivial, it remains a serious threat given the widespread use of MySQL databases in enterprise environments. The CVSS 3.0 scoring system assigns this vulnerability a base score of 4.4, with the availability impact category receiving the highest weight, indicating that successful exploitation can lead to complete denial of service conditions that severely impact database availability and system reliability.
The technical flaw manifests in how MySQL Server handles character set processing, specifically within the charset handling mechanisms that are fundamental to database operations. When an attacker with high privileges and network access attempts to exploit this vulnerability through multiple network protocols, the system becomes susceptible to triggering a condition that causes either a hang or frequent crashes that can be repeatedly triggered. This type of vulnerability represents a classic availability attack pattern where the attacker leverages legitimate system functions to create a resource exhaustion or state corruption condition that renders the database service completely non-responsive. The vulnerability's impact extends beyond simple service interruption as it can be repeatedly exploited to maintain persistent denial of service conditions, making it particularly dangerous in production environments where database availability is critical for business operations.
From an operational perspective, this vulnerability creates a significant risk for organizations relying on MySQL databases, particularly those with high availability requirements and mission-critical applications. The fact that exploitation requires high privileged access but can be achieved through network protocols means that both internal threat actors with elevated privileges and external attackers who have gained administrative access can potentially trigger the vulnerability. The complete denial of service impact can result in substantial business disruption, data access interruptions, and potential financial losses for organizations that depend on continuous database availability. The vulnerability's characteristics align with attack patterns documented in the MITRE ATT&CK framework under the privilege escalation and denial of service categories, where adversaries leverage system weaknesses to maintain access and disrupt services. Organizations may find this vulnerability particularly concerning as it affects multiple major version streams, indicating a fundamental flaw in the charset processing logic that was present across a wide range of MySQL implementations.
The mitigation strategies for CVE-2017-3648 should prioritize immediate patching of affected MySQL versions to the latest available releases that contain the necessary security fixes. Organizations should also implement network segmentation and access controls to limit the attack surface by restricting network access to MySQL servers and ensuring that only authorized administrative users have the necessary privileges to interact with database systems. Additionally, monitoring systems should be enhanced to detect unusual patterns of database connection behavior or repeated connection failures that might indicate exploitation attempts. Security teams should also consider implementing database firewalls or intrusion detection systems that can monitor for suspicious charset-related operations and network protocols that might be used to trigger the vulnerability. The vulnerability's classification under CWE 119, which deals with improper restriction of operations within a limited scope, indicates that the issue stems from inadequate bounds checking or memory management during charset processing operations, making proper input validation and access control measures critical defensive controls. Organizations should also conduct regular vulnerability assessments and penetration testing to identify potential exploitation vectors and ensure that their security measures remain effective against similar threats.