CVE-2003-0672 in pam-pgsql
Summary
by MITRE
Format string vulnerability in pam-pgsql 0.5.2 and earlier allows remote attackers to execute arbitrary code via the username that isp rovided during authentication, which is not properly handled when recording a log message.
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Analysis
by VulDB Data Team • 06/29/2021
The vulnerability described in CVE-2003-0672 represents a critical format string vulnerability within the pam-pgsql module version 0.5.2 and earlier. This authentication module serves as a Pluggable Authentication Module component that interfaces with PostgreSQL databases for user authentication purposes in Unix-like operating systems. The flaw arises from improper handling of user-provided input during log message generation, specifically when the username parameter is processed without adequate sanitization or formatting controls.
This format string vulnerability occurs because the application fails to properly validate or escape the username input before incorporating it into log messages that utilize format string functions. When an attacker provides a malicious username containing format specifiers such as %s, %d, or other format directives, these sequences can be interpreted by the logging function to access memory locations, potentially leading to arbitrary code execution. The vulnerability is particularly dangerous because it occurs during the authentication process when the system processes user input, making it accessible to remote attackers who can craft malicious usernames to exploit this weakness.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to gain unauthorized access to systems that rely on pam-pgsql for authentication. Attackers can leverage this vulnerability to execute arbitrary commands with the privileges of the authentication service, potentially escalating their access to full system control. The vulnerability affects the integrity and confidentiality of the authentication system, as malicious actors can manipulate log messages to inject code that executes when the system processes the log entries. This represents a serious security flaw that undermines the fundamental trust model of the authentication infrastructure.
Mitigation strategies for this vulnerability require immediate patching of the pam-pgsql module to version 0.5.3 or later, which contains the necessary fixes for proper input validation and format string handling. Organizations should implement input sanitization measures that prevent format specifiers from being processed in user-provided data, particularly when used in logging contexts. The fix should ensure that all user input is properly escaped or validated before being incorporated into format string operations. Additionally, system administrators should monitor log files for suspicious entries and implement proper access controls to limit the impact of potential exploitation attempts. This vulnerability aligns with CWE-134 which specifically addresses the use of format strings inappropriately, and relates to attack techniques in the MITRE ATT&CK framework under privilege escalation and execution categories. The vulnerability demonstrates the critical importance of input validation in security-critical components and highlights the need for secure coding practices in authentication modules that handle user-provided data.