CVE-2002-0817 in Super
Summary
by MITRE
Format string vulnerability in super for Linux allows local users to gain root privileges via a long command line argument.
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Analysis
by VulDB Data Team • 12/04/2024
The vulnerability identified as CVE-2002-0817 represents a critical format string flaw within the super utility on Linux systems, which operates as a privileged program for executing commands with elevated privileges. This vulnerability resides in the super command's handling of command line arguments, specifically when processing user input through format specifiers that are not properly validated or sanitized. The super utility, historically used for executing commands with root privileges, serves as a critical component in Unix-like systems where privilege escalation mechanisms are implemented. The flaw manifests when the program fails to properly escape or validate format specifiers in user-provided command line arguments, creating a potential path for malicious input to manipulate the program's execution flow.
The technical implementation of this vulnerability stems from improper input validation within the super utility's argument parsing mechanism. When a local user provides a command line argument containing format specifiers such as %n, %s, or other format string directives, the program processes these without adequate sanitization, potentially leading to stack corruption or information disclosure. This type of vulnerability falls under the CWE-134 classification, which specifically addresses the use of untrusted data in format string functions, a well-documented weakness in software security practices. The flaw allows attackers to exploit the format string vulnerability by carefully crafting command line arguments that contain format specifiers designed to write data to arbitrary memory locations or to read sensitive information from the stack.
The operational impact of this vulnerability is severe, as it provides local users with a direct path to privilege escalation from their current user context to root privileges. This represents a significant security risk in multi-user environments where users may have legitimate access to command line interfaces but should not possess administrative capabilities. The vulnerability essentially allows any local user to execute arbitrary code with the highest system privileges, potentially enabling complete system compromise. Attackers can leverage this weakness to modify system files, install malicious software, or extract sensitive data from the system, making it a critical concern for system administrators. The attack vector is particularly dangerous because it requires minimal privileges to exploit and can be executed from any location where the super utility is accessible, typically within standard shell environments.
Mitigation strategies for this vulnerability should focus on immediate patching of the super utility to ensure proper input validation and format string handling. System administrators must update their Linux distributions to include the patched versions of the super utility, which typically implement proper sanitization of command line arguments before processing them as format strings. Additionally, implementing proper input validation mechanisms that reject or escape format specifiers in command line arguments provides an additional layer of defense. The recommended approach includes configuring the system to prevent local users from executing the super utility directly, or implementing strict access controls that limit who can invoke privileged operations. Security monitoring should also be enhanced to detect unusual command line argument patterns that may indicate exploitation attempts. This vulnerability demonstrates the critical importance of proper input validation in privileged programs and aligns with ATT&CK technique T1068 which covers privilege escalation through the exploitation of system vulnerabilities. Organizations should also consider implementing principle of least privilege principles and regularly auditing system utilities to ensure they are not vulnerable to similar format string issues that could provide unauthorized privilege escalation capabilities.