CVE-2016-3065 in PostgreSQL
Summary
by MITRE
The (1) brin_page_type and (2) brin_metapage_info functions in the pageinspect extension in PostgreSQL before 9.5.x before 9.5.2 allows attackers to bypass intended access restrictions and consequently obtain sensitive server memory information or cause a denial of service (server crash) via a crafted bytea value in a BRIN index page.
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Analysis
by VulDB Data Team • 07/13/2022
The vulnerability identified as CVE-2016-3065 affects the pageinspect extension in PostgreSQL versions prior to 9.5.2, representing a critical security flaw that undermines the database system's access control mechanisms. This vulnerability specifically targets two functions within the pageinspect extension namely brin_page_type and brin_metapage_info which are designed to provide administrative information about BRIN index pages. The flaw arises from insufficient input validation and access control checks when processing crafted bytea values, allowing malicious actors to exploit these functions to gain unauthorized access to sensitive server memory information or trigger system crashes.
The technical implementation of this vulnerability stems from the improper handling of bytea data types within BRIN index page inspection functions. BRIN (Block Range INdex) is a storage access method designed for large tables that supports efficient range queries while maintaining minimal storage overhead. When attackers supply specially crafted bytea values to the brin_page_type and brin_metapage_info functions, the system fails to properly validate the input data structure, enabling attackers to manipulate memory access patterns and potentially read server memory contents that should remain restricted to privileged database operations. This represents a classic example of a buffer over-read or memory disclosure vulnerability that can be leveraged to extract sensitive information from the database server's memory space.
From an operational impact perspective, this vulnerability poses significant risks to database security and availability. Attackers who successfully exploit this flaw can either obtain sensitive server memory information that may contain database credentials, connection details, or other confidential data, or alternatively cause a denial of service condition that results in server crashes. The memory disclosure aspect aligns with CWE-200 (Information Exposure) and potentially CWE-125 (Out-of-bounds Read) categories, while the denial of service component relates to CWE-400 (Uncontrolled Resource Consumption) and CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The vulnerability's impact is particularly severe because it affects the core database functionality and can be exploited without requiring elevated privileges, making it a prime target for attackers seeking to compromise database systems.
The exploitation of this vulnerability demonstrates a clear path from initial access to potential information disclosure or service disruption, making it a critical concern for database administrators and security teams. Organizations running PostgreSQL versions prior to 9.5.2 should immediately implement mitigation strategies including applying the official security patches released by PostgreSQL, restricting access to the pageinspect extension functions, and implementing network-level controls to limit exposure to potentially malicious inputs. This vulnerability also highlights the importance of proper input validation and access control mechanisms in database extension components, as outlined in the ATT&CK framework under techniques related to privilege escalation and information gathering. The flaw serves as a reminder that even seemingly administrative functions within database systems can present significant security risks when not properly secured against malformed input data.