CVE-2006-0678 in PostgreSQL
Summary
by MITRE
PostgreSQL 7.3.x before 7.3.14, 7.4.x before 7.4.12, 8.0.x before 8.0.7, and 8.1.x before 8.1.3, when compiled with Asserts enabled, allows local users to cause a denial of service (server crash) via a crafted SET SESSION AUTHORIZATION command, a different vulnerability than CVE-2006-0553.
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Analysis
by VulDB Data Team • 06/15/2019
PostgreSQL versions 7.3.x before 7.3.14, 7.4.x before 7.4.12, 8.0.x before 8.0.7, and 8.1.x before 8.1.3 contain a critical vulnerability that enables local users to trigger a denial of service condition through specifically crafted SET SESSION AUTHORIZATION commands. This vulnerability specifically manifests when the database system is compiled with assertion checks enabled, creating a condition where malformed input can cause the server process to crash abruptly. The flaw represents a classic buffer over-read or improper input validation issue that occurs during the processing of session authorization commands, where the system fails to properly validate the length or format of the authorization identifier provided by users.
The technical implementation of this vulnerability stems from insufficient input validation within the session authorization handling code path. When a user executes a SET SESSION AUTHORIZATION command with carefully constructed parameters, the system's assertion mechanisms trigger a failure condition that leads to immediate process termination. This behavior aligns with CWE-129, which describes improper validation of length of input buffers, and CWE-248, which covers exposure of a resource to the wrong sphere. The vulnerability operates at the application level within the PostgreSQL backend processing, where the assertion failure occurs during command parsing rather than at the network or operating system level, making it particularly challenging to detect through traditional network-based security monitoring.
From an operational perspective, this vulnerability presents a significant risk to database availability and system stability. Local users who can execute commands against the PostgreSQL instance can exploit this flaw to cause repeated service interruptions, potentially leading to complete database unavailability. The impact extends beyond simple denial of service as system administrators may experience difficulties in maintaining service continuity, especially in environments where automated processes depend on database availability. The vulnerability affects multiple major versions of PostgreSQL, indicating it was a widespread issue in the codebase that required coordinated patching across different release branches. This type of vulnerability also falls under ATT&CK technique T1499.004, which covers network denial of service attacks, though in this case the attack vector is local rather than network-based.
The recommended mitigation strategy involves upgrading to the patched versions of PostgreSQL that address this specific assertion failure in session authorization handling. Organizations should prioritize patching all affected versions, particularly those running in production environments where local user access is possible. Additionally, system administrators should consider disabling assertion checks in production environments where the risk of exploitation is high, though this approach reduces the system's ability to detect other potential issues. Security monitoring should include detection of unusual session authorization command patterns and process termination events, as these may indicate attempted exploitation of this vulnerability. The vulnerability demonstrates the importance of proper input validation and robust error handling in database systems, particularly when assertion mechanisms are enabled in production environments.