CVE-2017-3649 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: Replication). Supported versions that are affected are 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-2017-3649 resides within the MySQL Server component, specifically within the Server: Replication subcomponent of Oracle MySQL database systems. This flaw affects a range of supported versions including all releases of MySQL 5.6 up to 5.6.36 and MySQL 5.7 up to 5.7.18, representing a significant portion of the MySQL server ecosystem that was in active use during the time of discovery. The vulnerability's classification as a remote attack vector with high privilege requirements indicates that exploitation requires an attacker with elevated network access permissions, though the accessibility of such privileges within database environments makes this threat particularly concerning.
The technical nature of this vulnerability manifests as a weakness in the replication mechanism that governs how MySQL servers synchronize data across multiple instances. The flaw specifically impacts the server's ability to handle certain replication operations, creating a condition where maliciously crafted replication requests can trigger system instability. This vulnerability operates through multiple network protocols, which expands the potential attack surface and makes detection more challenging for security monitoring systems. The complexity of the exploitation process, as indicated by the CVSS 3.0 score of 4.4 with high attack complexity, suggests that while not trivial to exploit, it remains within the realm of possibility for determined attackers who possess sufficient privileges and network access.
The operational impact of successful exploitation of CVE-2017-3649 is severe and directly targets system availability through a complete denial of service condition. When exploited, the vulnerability allows an attacker to cause the MySQL server to hang or repeatedly crash, effectively rendering the database service unavailable to legitimate users and applications. This type of attack can result in significant business disruption, particularly in environments where database availability is critical for application functionality and data integrity. The vulnerability's ability to cause frequently repeatable crashes means that even a single successful exploit can lead to prolonged service outages, requiring system administrators to perform manual intervention to restore service.
The security implications extend beyond simple service disruption, as this vulnerability aligns with the Common Weakness Enumeration (CWE) category for improper handling of replication data, which falls under CWE-254. This weakness represents a fundamental flaw in how the server processes replication commands, creating an avenue for attackers to manipulate the server's operational state. From an adversary perspective, this vulnerability maps to the MITRE ATT&CK framework's technique for Denial of Service, specifically targeting the Database Service component. The attack chain typically involves an attacker who has already gained access to the network and possesses sufficient privileges to establish replication connections, making this a particularly dangerous vulnerability in environments where network segmentation is not properly implemented.
Organizations affected by this vulnerability should implement immediate mitigations including upgrading to patched versions of MySQL Server, which would resolve the replication handling issue that allows for the denial of service condition. Network segmentation and access controls should be reviewed to limit the attack surface, particularly restricting replication connections to trusted network segments. Additionally, implementing monitoring solutions that can detect abnormal replication activity patterns would help identify potential exploitation attempts. The CVSS vector indicates that while the vulnerability requires high privilege access, the availability impact is severe, making it a critical priority for organizations that rely on MySQL for business-critical applications. Regular vulnerability assessments and penetration testing should be conducted to identify similar weaknesses in database configurations and to ensure that proper security controls are in place to prevent exploitation of such vulnerabilities.