CVE-2002-1400 in PostgreSQL
Summary
by MITRE
Heap-based buffer overflow in the repeat() function for PostgreSQL before 7.2.2 allows attackers to execute arbitrary code by causing repeat() to generate a large string.
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Analysis
by VulDB Data Team • 09/06/2025
The vulnerability identified as CVE-2002-1400 represents a critical heap-based buffer overflow within the PostgreSQL database management system affecting versions prior to 7.2.2. This flaw exists specifically within the repeat() function which is designed to repeat a given string a specified number of times. The vulnerability arises from insufficient input validation and memory allocation handling when processing large repeat operations, creating a condition where attacker-controlled input can cause the heap memory to be overwritten beyond its allocated boundaries. Such buffer overflow conditions are particularly dangerous as they can lead to arbitrary code execution, allowing malicious actors to gain control over the database server process.
The technical implementation of this vulnerability stems from the repeat() function's failure to properly validate the input parameters that determine how many times a string should be repeated. When an attacker provides a large value for the repeat count, the function attempts to allocate memory for the resulting string without adequate bounds checking. The heap allocation routine calculates the required memory based on the input value, but fails to account for potential integer overflow conditions or excessive memory requirements that could exceed the available heap space. This flaw falls under the CWE-121 heap-based buffer overflow category, which is classified as a common weakness in software design where data is written beyond the boundaries of allocated heap memory. The vulnerability can be exploited through database queries that invoke the repeat() function with maliciously crafted parameters, potentially allowing attackers to manipulate the heap memory layout and inject executable code.
The operational impact of this vulnerability extends beyond simple code execution, as it fundamentally compromises the integrity and availability of PostgreSQL database systems. An attacker who successfully exploits this vulnerability can execute arbitrary code with the privileges of the database process, which typically runs with elevated permissions on the server. This could lead to complete system compromise, data exfiltration, or the installation of persistent backdoors. The vulnerability affects database servers that process user input through SQL queries, making it particularly dangerous in web applications and other systems where user-provided data is directly passed to database functions. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.002 for command and script interpreter execution, as attackers can leverage the heap overflow to inject and execute malicious code within the database environment. The vulnerability also represents a significant risk to data confidentiality and integrity, as attackers can potentially modify or delete database contents while maintaining access to the system.
Mitigation strategies for CVE-2002-1400 primarily focus on immediate patching and implementing defensive programming practices. Organizations should upgrade to PostgreSQL version 7.2.2 or later, which contains the necessary fixes for the heap overflow condition in the repeat() function. Additionally, administrators should implement strict input validation and parameter sanitization for all database queries, particularly those involving string manipulation functions. The implementation of proper bounds checking and memory allocation limits can prevent the exploitation of similar vulnerabilities in other database functions. Security monitoring should be enhanced to detect unusual query patterns that might indicate attempts to exploit heap overflow conditions, including monitoring for large repeat operations or memory allocation anomalies. Database administrators should also consider implementing privilege separation and least-privilege principles to minimize the potential impact of successful exploits. The vulnerability serves as a reminder of the importance of secure coding practices and proper memory management in database systems, particularly for functions that handle user input and perform dynamic memory allocation operations.