CVE-2021-32027 in PostgreSQL
Summary
by MITRE • 06/02/2021
A flaw was found in postgresql in versions before 13.3, before 12.7, before 11.12, before 10.17 and before 9.6.22. While modifying certain SQL array values, missing bounds checks let authenticated database users write arbitrary bytes to a wide area of server memory. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
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Analysis
by VulDB Data Team • 10/15/2024
This vulnerability represents a critical memory corruption flaw in postgresql database systems that affects multiple major versions including 13.3, 12.7, 11.12, 10.17, and 9.6.22. The issue stems from insufficient bounds checking during the modification of SQL array values, creating a condition where authenticated users can potentially overwrite arbitrary memory locations. This type of vulnerability falls under the CWE-129 weakness category, specifically addressing insufficient bounds checking in array operations. The flaw manifests when postgresql processes certain array modifications, allowing malicious users to write data beyond the intended memory boundaries. The vulnerability is particularly dangerous because it enables attackers to manipulate memory contents in a wide area of the server's memory space, potentially affecting critical system components and data structures. The attack requires authentication to the database system, making it accessible to users with legitimate database access privileges, which could include developers, administrators, or applications with database credentials. This memory corruption vulnerability directly impacts the confidentiality, integrity, and availability of the database system as outlined in the attack pattern taxonomy. The potential for arbitrary memory writes creates numerous attack vectors including data exfiltration, integrity compromise, and system instability leading to availability disruption.
The operational impact of this vulnerability extends beyond simple data corruption, as it can enable attackers to gain deeper system access and potentially escalate privileges. When authenticated users can write arbitrary bytes to memory, they may overwrite critical data structures, function pointers, or control flow information within the postgresql process. This memory manipulation capability allows for various attack scenarios including information disclosure through memory dumps, data modification through targeted memory corruption, and denial of service through system crashes or hangs. The vulnerability affects the fundamental integrity of the database system since it allows for unauthorized modification of memory contents that should remain protected. Security professionals should note that this issue aligns with several attack techniques documented in the ATT&CK framework, particularly those related to privilege escalation and defense evasion through memory corruption attacks. The impact on data confidentiality is severe since attackers can potentially access sensitive information stored in memory regions that are normally protected from direct access. System integrity is compromised because the database can be manipulated to return incorrect results or behave unpredictably. The availability aspect becomes critical as memory corruption can lead to process crashes, system instability, or complete database service outages that affect business operations.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected postgresql versions to the latest stable releases containing the fix. Organizations should implement comprehensive monitoring for unauthorized database access attempts and unusual array modification patterns that might indicate exploitation attempts. Database administrators should review and restrict database user permissions to minimize the attack surface, ensuring that only necessary users have access to array manipulation functions. Network segmentation and access controls should be strengthened to limit database server exposure and reduce the likelihood of unauthorized access. The implementation of database activity monitoring tools can help detect anomalous array operation patterns that might indicate exploitation attempts. Security teams should conduct regular vulnerability assessments and penetration testing to identify and remediate similar memory corruption issues in other database systems and applications. Additionally, maintaining detailed audit logs of database activities, particularly array operations, enables forensic analysis in case of suspected exploitation. The fix implemented by postgresql developers addresses the core bounds checking issue by ensuring proper validation of array indices before memory operations, preventing the arbitrary memory writes that were previously possible. Organizations should also consider implementing application-level protections such as input validation and parameterized queries to reduce the risk of exploitation even if other security controls fail. Regular security awareness training for database administrators and developers can help prevent configuration errors that might exacerbate the vulnerability's impact.