CVE-2007-3280 in PostgreSQL
Summary
by MITRE
The Database Link library (dblink) in PostgreSQL 8.1 implements functions via CREATE statements that map to arbitrary libraries based on the C programming language, which allows remote authenticated superusers to map and execute a function from any library, as demonstrated by using the system function in libc.so.6 to gain shell access.
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Analysis
by VulDB Data Team • 07/26/2019
The vulnerability described in CVE-2007-3280 represents a critical privilege escalation flaw within PostgreSQL's Database Link library implementation that fundamentally undermines database security boundaries. This vulnerability exists in PostgreSQL version 8.1 and specifically affects the dblink extension which provides functions for connecting to remote databases through CREATE statements that map to arbitrary C libraries. The flaw allows authenticated superusers to manipulate the library mapping mechanism to execute arbitrary code with the privileges of the database server process, effectively creating a backdoor for malicious actors who can leverage this capability to gain complete control over the database system.
The technical implementation of this vulnerability stems from insufficient input validation and privilege management within the dblink library's function mapping mechanism. When superusers create database links using the CREATE statements, they can specify arbitrary library names and function names that map to shared libraries on the system. The vulnerability becomes exploitable because the system does not properly validate or restrict which libraries can be loaded, allowing attackers to reference system libraries such as libc.so.6 and leverage functions like the system() call to execute arbitrary commands. This mapping mechanism bypasses normal security controls and creates an execution path that directly translates user-supplied input into system-level operations without proper sanitization.
From an operational perspective, this vulnerability has severe implications for database security and system integrity. An authenticated superuser can exploit this flaw to execute shell commands with the privileges of the database service account, potentially leading to complete system compromise. The impact extends beyond just database access as the compromised database server may have access to sensitive data, network resources, and potentially other systems within the organization's infrastructure. The vulnerability is particularly dangerous because it requires only authenticated access to a superuser account, which is often considered a privileged position within database environments and may be less strictly monitored than other system access points. This creates a scenario where insider threats or compromised accounts can escalate privileges to system-level access through database functions.
The vulnerability aligns with CWE-20, which addresses "Improper Input Validation," and demonstrates how insufficient validation of user-supplied data in system-level operations can create dangerous execution paths. From an attack perspective, this vulnerability maps to several ATT&CK techniques including privilege escalation through exploitation of software vulnerabilities and execution through legitimate system processes. The attack vector requires an authenticated superuser account but can be executed remotely if the database is accessible over a network, making it particularly concerning for organizations with exposed database services. Organizations should implement immediate mitigations including restricting superuser privileges, disabling unnecessary database extensions, and implementing strict library loading policies that prevent arbitrary library mapping. The recommended approach involves updating to patched versions of PostgreSQL, implementing proper access controls, and monitoring for suspicious database link creation activities to detect potential exploitation attempts.
This vulnerability highlights the critical importance of proper privilege separation and input validation in database systems, particularly when dealing with extensions that provide direct system-level access capabilities. The flaw demonstrates how database security can be compromised through seemingly innocuous features that provide excessive flexibility without proper security boundaries. Organizations should conduct comprehensive security reviews of all database extensions and ensure that any functionality providing system-level access is properly audited and restricted to prevent similar vulnerabilities from being exploited in other database systems or applications.