CVE-2011-1074 in FreeBSD
Summary
by MITRE
crontab.c in crontab in FreeBSD allows local users to determine the existence of arbitrary directories via a command-line argument composed of a directory name concatenated with a directory traversal sequence that leads to the /etc/crontab pathname.
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Analysis
by VulDB Data Team • 01/09/2018
The vulnerability identified as CVE-2011-1074 resides within the FreeBSD crontab utility, specifically in the crontab.c source file. This issue represents a directory traversal weakness that enables local attackers to probe the existence of arbitrary directories on the system. The flaw manifests when the crontab command processes command-line arguments containing directory names concatenated with traversal sequences designed to access the /etc/crontab file path. This vulnerability falls under the category of path traversal attacks and is classified as CWE-22 according to the Common Weakness Enumeration framework.
The technical implementation of this vulnerability exploits the insufficient input validation within the crontab utility's argument parsing mechanism. When a local user provides a specially crafted command-line argument containing directory traversal sequences such as ../ or similar patterns, the crontab utility fails to properly sanitize these inputs before attempting to access system files. This inadequate sanitization allows the utility to traverse the filesystem hierarchy and determine whether specific directories exist, effectively providing attackers with directory enumeration capabilities that should remain restricted to authorized system processes.
From an operational perspective, this vulnerability presents a significant information disclosure risk for FreeBSD systems running the affected crontab utility. Local users can leverage this weakness to discover the existence of directories that might otherwise be hidden or protected, potentially revealing system structure and configuration details that could aid in further exploitation attempts. The impact extends beyond simple directory enumeration as it provides attackers with knowledge about the filesystem layout, which could be used to plan more sophisticated attacks targeting other system components. This vulnerability directly relates to the ATT&CK technique T1083 (File and Directory Discovery) and represents a privilege escalation vector that could be combined with other weaknesses to achieve broader system compromise.
The mitigation strategies for CVE-2011-1074 should focus on implementing proper input validation and sanitization within the crontab utility. System administrators should ensure that FreeBSD systems are updated with patches addressing this vulnerability, as the original flaw stems from inadequate path validation logic. Additionally, implementing proper access controls and restricting local user privileges where possible can reduce the potential impact of such enumeration attacks. The fix typically involves strengthening the argument parsing logic to reject or properly sanitize directory traversal sequences before they can influence filesystem access operations. Organizations should also consider implementing monitoring solutions to detect anomalous crontab usage patterns that might indicate exploitation attempts. This vulnerability demonstrates the importance of proper input validation in system utilities and highlights how seemingly benign file access operations can expose system internals when inadequate security measures are in place.