CVE-2012-6097 in cronie
Summary
by MITRE
File descriptor leak in cronie 1.4.8, when running in certain environments, might allow local users to read restricted files, as demonstrated by reading /etc/crontab.
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Analysis
by VulDB Data Team • 12/29/2024
The vulnerability identified as CVE-2012-6097 represents a critical file descriptor leak within the cronie package version 1.4.8 that fundamentally compromises the security boundaries designed to protect sensitive system files. This flaw specifically manifests when cronie operates in certain environmental configurations, creating a condition where local attackers can exploit improper file descriptor handling to gain unauthorized access to restricted system resources. The vulnerability directly impacts the integrity of the Unix file permission model by allowing unauthorized reading of files that should remain protected, with the /etc/crontab file serving as a prime example of the type of sensitive information that becomes accessible through this exploit.
The technical root cause of this vulnerability stems from improper resource management within the cronie daemon's execution environment, where file descriptors are not properly closed or managed during process execution. This creates a persistent exposure that allows malicious processes to inherit and utilize these leaked file descriptors to access files that would normally be restricted to specific user groups or processes. The flaw operates at the operating system level through the file descriptor table mechanism, where processes maintain references to open files and resources that should be properly cleaned up after use. When these cleanup operations fail, the inherited file descriptors can be leveraged by local users to access restricted files that were opened by the cronie process but not properly closed.
The operational impact of this vulnerability extends beyond simple information disclosure, as it represents a fundamental breakdown in the principle of least privilege that governs secure system operations. Local users who can execute processes on the system can leverage this flaw to read sensitive configuration files that contain critical system information, including but not limited to scheduled tasks, user permissions, and potentially credential information stored in the crontab files. This access can enable attackers to escalate their privileges, discover system architecture details, or identify other potential attack vectors within the environment. The vulnerability particularly affects systems where cronie is configured to run with elevated privileges, as the leaked file descriptors can be used to access files that would normally require root access to read.
Security professionals should consider this vulnerability in the context of the CWE-242 weakness category, which specifically addresses the use of potentially dangerous functions that can lead to resource leaks and security vulnerabilities. The ATT&CK framework would classify this as a privilege escalation technique under the "Exploitation for Privilege Escalation" domain, where local users leverage system-level flaws to gain elevated access rights. Mitigation strategies should include immediate patching of affected cronie installations to version 1.4.9 or later, where the file descriptor leak has been corrected through proper resource management practices. System administrators should also implement monitoring for abnormal file access patterns and consider restricting the execution environment of cronie processes to minimize the potential impact of such vulnerabilities. Additional defensive measures include regular security audits of scheduled tasks and file permissions, along with implementing proper process isolation techniques to prevent the inheritance of sensitive file descriptors across different execution contexts.