CVE-2014-9770 in systemd
Summary
by MITRE
tmpfiles.d/systemd.conf in systemd before 214 uses weak permissions for journal files under (1) /run/log/journal/%m and (2) /var/log/journal/%m, which allows local users to obtain sensitive information by reading these files.
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Analysis
by VulDB Data Team • 10/19/2018
The vulnerability identified as CVE-2014-9770 represents a critical privilege escalation and information disclosure weakness within the systemd initialization system. This flaw specifically affects systemd versions prior to 214 and resides in the tmpfiles.d/systemd.conf configuration file that governs the creation and permissions of journal files. The vulnerability stems from the improper permission settings applied to journal directories and their contents, creating a persistent security weakness that local attackers can exploit to gain unauthorized access to sensitive system information.
The technical implementation of this vulnerability involves the systemd tmpfiles.d configuration mechanism which establishes journal file locations at two primary paths: /run/log/journal/%m and /var/log/journal/%m. These paths are designed to store system logs and application logs respectively, but due to weak permission settings, unauthorized local users can read the contents of these journal files. The %m placeholder represents the machine ID, ensuring unique paths per system instance. The improper permissions typically manifest as overly permissive file modes that allow world-readable access to log files containing potentially sensitive data such as system events, application behavior, user activities, and other operational information that could aid in further attacks or system compromise.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with valuable intelligence for subsequent exploitation attempts. System logs often contain sensitive information including but not limited to authentication attempts, system errors, application crash details, and potentially credential information that may be inadvertently logged. This information can be leveraged for privilege escalation attacks, social engineering, or to craft more sophisticated targeted attacks against the system. The vulnerability is particularly concerning because it affects the core system logging infrastructure, making it a persistent threat that remains active as long as the vulnerable systemd version is in use.
From a cybersecurity framework perspective, this vulnerability maps directly to CWE-732: Incorrect Permission Assignment for Critical Resource, which specifically addresses situations where critical system resources are assigned incorrect permissions that allow unauthorized access. The ATT&CK framework categorizes this under T1083: File and Directory Discovery, as the vulnerability enables local users to identify and access sensitive log files. Additionally, it relates to T1005: Data from Local System, representing a method for extracting sensitive information from the target system. The weakness also aligns with T1566: Phishing, as the information obtained from journal files could be used to craft more convincing social engineering attacks.
The recommended mitigation strategy involves upgrading to systemd version 214 or later, where the permissions for journal files have been properly configured to restrict access to authorized users only. System administrators should also implement regular monitoring of journal file access patterns to detect potential unauthorized access attempts. Additional protective measures include implementing proper log rotation policies, ensuring that sensitive information is not logged in plain text, and maintaining regular system patching procedures. Organizations should also consider implementing file integrity monitoring solutions to detect any unauthorized changes to the tmpfiles.d configuration files or journal directories. The vulnerability underscores the importance of proper privilege separation and access control mechanisms within system initialization frameworks, as these components often serve as foundational elements that can affect the entire system security posture.