CVE-2012-0961 in APT
Summary
by MITRE
Apt 0.8.16~exp5ubuntu13.x before 0.8.16~exp5ubuntu13.6, 0.8.16~exp12ubuntu10.x before 0.8.16~exp12ubuntu10.7, and 0.9.7.5ubuntu5.x before 0.9.7.5ubuntu5.2, as used in Ubuntu, uses world-readable permissions for /var/log/apt/term.log, which allows local users to obtain sensitive shell information by reading the log file.
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Analysis
by VulDB Data Team • 04/20/2021
The vulnerability described in CVE-2012-0961 represents a critical access control flaw in the Advanced Package Tool (Apt) software package distribution system. This issue affects multiple Ubuntu releases including versions 0.8.16 and 0.9.7.5, specifically within the apt package management infrastructure. The core problem lies in the improper file permission settings for the terminal log file located at /var/log/apt/term.log, which is accessible to all users on the system.
The technical flaw manifests through weak file permissions that grant world-read access to the terminal log file, creating an information disclosure vulnerability. When users interact with the apt package management system through terminal sessions, commands executed during package installation, removal, or updates are recorded in this log file. However, due to the world-readable permissions, any local user on the system can access this log file and extract potentially sensitive shell command information. This includes command sequences, package names, and other operational details that could reveal system configuration, user activities, or even reveal potential attack vectors.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates opportunities for privilege escalation and system reconnaissance. Local attackers can leverage this access to gather intelligence about system administration activities, package management operations, and potentially identify vulnerable system configurations or outdated software versions. The vulnerability aligns with CWE-276, which specifically addresses improper file permissions and inadequate access control mechanisms. From an attack perspective, this flaw fits within the ATT&CK framework under the T1083 - File and Directory Discovery tactic, as it enables adversaries to identify and access sensitive log files containing system information.
The vulnerability affects the fundamental security model of the Ubuntu package management system by undermining the principle of least privilege. System administrators expect that sensitive operational logs would be protected from unauthorized access, particularly when these logs contain command execution details that could reveal system state or administrative activities. The flaw essentially creates an unintended information leak channel that bypasses normal access controls and could be exploited by malicious users to gain insights into system operations, potentially leading to more sophisticated attacks targeting package management processes or specific system configurations.
Mitigation strategies for this vulnerability include implementing proper file permissions on the affected log file, ensuring that only authorized users or processes can access the terminal log. System administrators should immediately verify and correct the file permissions for /var/log/apt/term.log to restrict access to the root user and potentially the apt package manager process only. The recommended fix involves setting appropriate ownership and permissions using standard unix file permission mechanisms, typically restricting access to root only. Additionally, system administrators should implement regular security audits to identify and correct similar permission issues across other system log files. This vulnerability highlights the importance of proper file permission management in package management systems and emphasizes the need for comprehensive security testing of system components that handle sensitive operational data. The issue demonstrates how seemingly minor configuration errors in file permissions can create significant security risks that persist across multiple system versions and distributions.