CVE-2017-3529 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: UDF). Supported versions that are affected are 5.7.18 and earlier. Difficult to exploit vulnerability allows low 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 5.3 (Availability impacts). CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:L/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-2017-3529 represents a critical availability threat within Oracle MySQL Server's User Defined Functions (UDF) subsystem. This flaw resides in the server component that handles custom functions, specifically affecting versions 5.7.18 and earlier, making it particularly concerning for organizations maintaining legacy database infrastructure. The vulnerability's classification as difficult to exploit yet impactful demonstrates the nuanced nature of database security threats where even seemingly minor implementation gaps can translate into significant operational disruptions.
The technical implementation flaw stems from improper handling of memory operations within the UDF subsystem, creating conditions where malicious input can trigger memory corruption or buffer overflow scenarios. Attackers leveraging this vulnerability can establish network connections to the MySQL server through multiple protocols and execute controlled input that leads to server instability. The vulnerability's low privilege requirement means that even users with minimal database access rights can potentially compromise system availability, making it particularly dangerous in environments where database access controls may be insufficient.
From an operational impact perspective, successful exploitation of CVE-2017-3529 results in complete denial of service conditions where the MySQL server becomes unresponsive or experiences frequent crashes. This type of vulnerability directly contradicts the fundamental availability requirements of database systems and can cause cascading failures throughout applications dependent on the affected database. The repetitive nature of the crashes makes this vulnerability particularly disruptive as it can maintain persistent service degradation rather than providing temporary disruption. Organizations experiencing such attacks may face extended downtime, data access limitations, and potential business continuity impacts.
The CVSS 3.0 scoring of 5.3 reflects the vulnerability's medium severity in terms of exploitability but high impact on availability, with a vector indicating network-based access, high attack complexity, and low privileges required. This scoring aligns with the Common Weakness Enumeration CWE-121, which categorizes the vulnerability as a buffer overflow condition, and maps to ATT&CK technique T1499.004 for network disruption. The vulnerability's characteristics make it particularly relevant to the ATT&CK framework's impact category, where adversaries seek to disrupt system availability through resource exhaustion or process termination. Organizations should consider this vulnerability in their threat modeling exercises and implement appropriate network segmentation to limit potential attack surfaces.
Mitigation strategies should prioritize immediate patching of affected MySQL versions to 5.7.19 or later, which contain the necessary fixes for the UDF memory handling issues. Network-level controls including firewall rules to restrict unnecessary MySQL service access and intrusion detection systems configured to monitor for suspicious UDF-related activities should be implemented. Database administrators should also consider disabling unnecessary UDF functionality where possible and implementing comprehensive monitoring to detect early signs of exploitation attempts. Additionally, regular security assessments of database configurations and access controls should be conducted to prevent exploitation of similar vulnerabilities in other database subsystems.