CVE-2005-0247 in PostgreSQL
Summary
by MITRE
Multiple buffer overflows in gram.y for PostgreSQL 8.0.1 and earlier may allow attackers to execute arbitrary code via (1) a large number of variables in a SQL statement being handled by the read_sql_construct function, (2) a large number of INTO variables in a SELECT statement being handled by the make_select_stmt function, (3) a large number of arbitrary variables in a SELECT statement being handled by the make_select_stmt function, and (4) a large number of INTO variables in a FETCH statement being handled by the make_fetch_stmt function, a different set of vulnerabilities than CVE-2005-0245.
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Analysis
by VulDB Data Team • 07/05/2025
The vulnerability described in CVE-2005-0247 represents a critical buffer overflow issue within the PostgreSQL database management system version 8.0.1 and earlier. This flaw exists in the gram.y file which serves as the yacc/bison grammar definition file for SQL statement parsing within the PostgreSQL backend. The buffer overflows occur during the parsing of specific SQL constructs, making this a parser-based vulnerability that can be exploited through malicious SQL input. The affected functions include read_sql_construct, make_select_stmt, and make_fetch_stmt, which are integral components of PostgreSQL's SQL statement processing pipeline. These functions handle various SQL constructs including variable assignments, SELECT statements with INTO clauses, and FETCH operations, creating multiple attack vectors for potential exploitation.
The technical implementation of this vulnerability stems from inadequate input validation and buffer size checking within the SQL parser. When PostgreSQL processes SQL statements containing excessive variables or complex constructs, the parser fails to properly validate the number of variables being processed, leading to memory corruption through buffer overflows. The specific functions affected demonstrate different aspects of the vulnerability: the read_sql_construct function handles general SQL construct parsing with variable assignments, while make_select_stmt processes SELECT statements with INTO variables and arbitrary variable assignments. The make_fetch_stmt function specifically addresses FETCH operations involving INTO variables. Each of these functions operates within the context of PostgreSQL's grammar parsing framework, where insufficient bounds checking allows attackers to overflow fixed-size buffers and potentially overwrite adjacent memory regions. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation in parser implementations.
The operational impact of CVE-2005-0247 is severe and potentially catastrophic for PostgreSQL deployments. Successful exploitation of these buffer overflows could enable remote attackers to execute arbitrary code with the privileges of the PostgreSQL database process, potentially leading to complete system compromise. The vulnerability affects the database server's ability to process legitimate SQL statements, creating both denial-of-service conditions and opportunities for privilege escalation. Attackers could leverage these vulnerabilities to gain unauthorized access to database contents, modify or delete sensitive information, or establish persistent backdoors within the database environment. The multiple attack vectors increase the exploitability of this vulnerability, as different SQL constructs can be used to trigger the same underlying buffer overflow conditions. This vulnerability directly relates to ATT&CK technique T1059.007 for command and scripting interpreter, and T1068 for exploit for privilege escalation, making it particularly dangerous in environments where database administrators have elevated system privileges.
Mitigation strategies for CVE-2005-0247 require immediate action to address the core parsing vulnerabilities within PostgreSQL. Organizations should prioritize upgrading to PostgreSQL version 8.0.2 or later, where these buffer overflow issues have been resolved through proper input validation and bounds checking. System administrators should implement input validation measures at the application level, including limiting the number of variables allowed in SQL statements and implementing proper SQL statement length restrictions. Database firewalls and intrusion prevention systems can provide additional layers of protection by monitoring for suspicious SQL patterns that might indicate attempts to exploit these vulnerabilities. Network segmentation and access control measures should be implemented to limit exposure of PostgreSQL instances to untrusted networks. Security monitoring should include detection of unusual SQL statement patterns and excessive variable counts that could indicate exploitation attempts. The vulnerability demonstrates the importance of proper memory management in parser implementations and serves as a reminder of the critical security implications of buffer overflow vulnerabilities in database systems. Organizations should also consider implementing automated patch management processes to ensure timely deployment of security updates and maintain comprehensive vulnerability assessment programs to identify similar issues in other database components.