CVE-2017-3642 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: Optimizer). 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-2017-3642 resides within the MySQL Server component, specifically within the Server: Optimizer subcomponent, affecting MySQL versions 5.7.18 and earlier. This represents a significant security concern as it operates within the core database engine optimization functionality that processes complex query execution plans. The vulnerability manifests as a flaw in how the optimizer handles certain query structures, creating a pathway for exploitation that can be leveraged by attackers with high privileges and network access.
This vulnerability operates through multiple network protocols and can be exploited by attackers who possess elevated privileges within the MySQL environment. The technical nature of the flaw involves the optimizer's handling of specific query execution paths that can trigger memory corruption or resource management issues. The vulnerability's classification as easily exploitable indicates that the attack vectors are well-understood and the conditions for successful exploitation are relatively straightforward to establish. The CVSS 3.0 scoring system assigns it a base score of 4.9, reflecting the availability impact of 8.0, which suggests that successful exploitation can result in complete denial of service conditions that can either hang the MySQL server or cause repeated crashes that effectively render the database service unavailable.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire database infrastructure. When exploited, the vulnerability can cause MySQL Server to enter a state where it becomes unresponsive or continuously crashes, creating a complete denial of service scenario that affects all database operations. This type of vulnerability is particularly dangerous in production environments where database availability is critical for business operations, as it can lead to extended downtime and potential data loss scenarios. The vulnerability's impact is amplified by the fact that it requires only high privileged access, meaning that attackers who have already gained administrative access to the database can easily leverage this flaw to cause maximum disruption.
Organizations should implement immediate mitigations including upgrading to MySQL versions that have patched this vulnerability, typically versions beyond 5.7.18. The patching process should be carefully managed to ensure compatibility with existing database applications and configurations. Network segmentation and access control measures should be reinforced to limit the attack surface and reduce the likelihood of unauthorized access to privileged database accounts. Additionally, monitoring systems should be enhanced to detect unusual patterns of database server behavior that might indicate exploitation attempts. This vulnerability aligns with CWE-129, which addresses issues related to improper validation of input, and can be mapped to ATT&CK technique T1499 which covers network denial of service attacks. The vulnerability demonstrates the critical importance of maintaining current database software versions and implementing robust access controls to prevent privilege escalation scenarios that could lead to such devastating availability impacts.