CVE-2018-1058 in PostgreSQL
Summary
by MITRE • 01/25/2023
A flaw was found in the way Postgresql allowed a user to modify the behavior of a query for other users. An attacker with a user account could use this flaw to execute code with the permissions of superuser in the database. Versions 9.3 through 10 are affected.
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Analysis
by VulDB Data Team • 01/25/2023
The vulnerability identified as CVE-2018-1058 represents a critical privilege escalation flaw within the PostgreSQL database management system that directly impacts version ranges from 9.3 through 10. This issue stems from insufficient access controls and improper privilege validation mechanisms that allow authenticated users to manipulate query execution behavior in ways that can compromise the entire database system. The flaw specifically resides in how PostgreSQL handles user-defined functions and query modifications, creating an avenue for malicious actors to elevate their privileges beyond what should be permitted for standard database users.
The technical implementation of this vulnerability involves a design flaw in PostgreSQL's privilege checking mechanisms that occurs during query execution phases where user-defined functions can inadvertently modify the execution context for other users. When an attacker with a standard user account exploits this weakness, they can manipulate the database's internal query processing to execute arbitrary code with superuser privileges. This occurs through the manipulation of function definitions and query plans that are cached or shared across different user sessions, effectively bypassing normal access control restrictions. The vulnerability is categorized under CWE-276 as improper privilege management, where the system fails to properly enforce access controls during query execution.
The operational impact of this vulnerability is severe as it allows an attacker to completely compromise database security through a single authenticated session. Once exploited, the attacker gains superuser privileges which enables them to access all database objects, modify or delete data, create new users, and potentially escalate to system-level access if database users have elevated system permissions. The vulnerability affects database operations across all supported versions, making it particularly dangerous for organizations that have not yet upgraded to patched versions. The flaw can be exploited remotely through standard database connections, making it accessible to attackers with minimal network presence requirements.
Mitigation strategies for CVE-2018-1058 primarily focus on immediate version upgrades to patched PostgreSQL releases that address the privilege escalation mechanism. Organizations should implement the latest security patches from PostgreSQL, particularly versions 9.3.20, 9.4.15, 9.5.10, 9.6.6, and 10.1, which contain fixes for the privilege checking implementation. Additionally, database administrators should implement strict access controls by limiting user privileges, reviewing existing user permissions, and implementing the principle of least privilege. The mitigation approach aligns with ATT&CK technique T1068 which addresses privilege escalation through the exploitation of system vulnerabilities, requiring organizations to maintain updated security configurations and monitor for unauthorized privilege changes. Network segmentation and database activity monitoring should also be implemented to detect potential exploitation attempts.