CVE-2021-2001 in MySQL Server
Summary
by MITRE • 01/20/2021
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 5.6.50 and prior, 5.7.30 and prior and 8.0.17 and prior. 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 3.1 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.1/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 • 02/17/2021
The vulnerability identified as CVE-2021-2001 resides within the MySQL Server optimizer component of Oracle MySQL database systems, representing a significant availability risk that affects multiple version branches including 5.6.50 and earlier, 5.7.30 and earlier, and 8.0.17 and earlier releases. This flaw operates at the core optimization layer where MySQL processes and evaluates query execution plans, making it particularly dangerous as it can be triggered through various network protocols that MySQL supports. The vulnerability's classification as easily exploitable indicates that sophisticated attackers with high privileges and network access can leverage this weakness to compromise the targeted MySQL server instances.
The technical nature of this vulnerability manifests as a condition that allows attackers to induce a hang or cause frequently repeatable crashes within the MySQL server process, effectively leading to a complete denial of service scenario. The underlying mechanism appears to involve the optimizer's handling of specific query structures or execution paths that, when processed, trigger internal server instability. This behavior aligns with common patterns found in software vulnerabilities classified under CWE-121, which deals with stack-based buffer overflow conditions, though the specific manifestation here relates to resource exhaustion or internal state corruption within the optimizer module. The attack vector requires network access and high privilege levels, suggesting that the vulnerability may be exploitable through authenticated connections or when attackers have already gained sufficient access to the system.
The operational impact of CVE-2021-2001 extends beyond simple service disruption, as the complete denial of service it enables can severely impact database availability and application functionality across systems relying on MySQL. Organizations utilizing affected MySQL versions face potential business disruption, data access limitations, and increased operational overhead due to system recovery requirements. The CVSS 3.1 Base Score of 4.9 indicates a medium severity vulnerability with significant availability implications, while the vector analysis reveals that the attack requires network access (AV:N) with low complexity (AC:L) but necessitates high privileges (PR:H). This combination suggests that while the attack is technically straightforward, it requires an attacker to have already established a privileged network presence within the target environment. The vulnerability's exploitation could result in cascading effects throughout database-dependent applications, potentially affecting multiple services and business processes that rely on consistent database availability.
Mitigation strategies for CVE-2021-2001 should prioritize immediate patching of affected MySQL server installations to the latest available versions that contain the relevant security fixes. Organizations should also implement network segmentation and access controls to limit privileged network access to MySQL servers, thereby reducing the attack surface for potential exploitation. Monitoring systems should be enhanced to detect unusual patterns in database server behavior or frequent crash occurrences that might indicate exploitation attempts. Additionally, implementing proper privilege management and least-privilege access controls can limit the potential damage from successful attacks, as the vulnerability requires high-privileged access to exploit effectively. Security teams should also consider deploying intrusion detection systems that can monitor for protocol-specific patterns associated with the vulnerability, while maintaining regular backup and recovery procedures to minimize downtime in case of successful exploitation attempts. The ATT&CK framework classification for this vulnerability would align with T1499.004 for Network Denial of Service and potentially T1078 for Valid Accounts, as the requirement for high privileges suggests exploitation through legitimate access channels rather than brute force attacks.