CVE-2010-0792 in fcron
Summary
by MITRE
fcrontab in fcron before 3.0.5 allows local users to read arbitrary files via a symlink attack on an unspecified file.
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Analysis
by VulDB Data Team • 05/01/2026
The vulnerability identified as CVE-2010-0792 affects the fcrontab utility within the fcron package version 3.0.4 and earlier. This issue represents a classic symlink attack scenario that exploits improper file handling during the execution of cron-related operations. The vulnerability stems from insufficient validation of file paths when processing cron job configurations, creating a window of opportunity for malicious local users to access files they should not be authorized to read.
The technical flaw manifests in the way fcron handles file operations when processing fcrontab commands. During normal operation, the system creates temporary files or interacts with specific file paths to manage cron job configurations. However, the vulnerability allows attackers to manipulate symbolic links in the filesystem to redirect these operations to arbitrary files of their choosing. This occurs because the system does not properly verify the target of symbolic links before performing file operations, enabling attackers to substitute legitimate configuration files with maliciously crafted symbolic links that point to sensitive system files.
The operational impact of this vulnerability extends beyond simple information disclosure. Local users who can execute fcrontab commands gain the ability to read any file that the fcron process has access to, potentially including system configuration files, password hashes, or other sensitive data. This represents a privilege escalation vector that could be exploited to gather intelligence for further attacks or to access credentials that could be used to compromise additional system resources. The attack requires local system access but does not need elevated privileges, making it particularly concerning for multi-user systems where users may have varying levels of access.
This vulnerability aligns with CWE-59, which describes improper handling of symbolic links, and represents a specific instance of path traversal issues in Unix-like systems. The attack pattern corresponds to techniques described in the ATT&CK framework under T1059 for command and scripting interpreter and T1566 for credential access through file system manipulation. The issue demonstrates how seemingly benign file processing operations can create security holes when proper input validation and file path resolution mechanisms are not implemented. The vulnerability highlights the importance of implementing proper file access controls and ensuring that symbolic link resolution occurs in a secure manner to prevent attackers from manipulating file access patterns.
The recommended mitigation involves upgrading to fcron version 3.0.5 or later, which includes proper handling of symbolic links during fcrontab operations. System administrators should also implement proper file permissions and access controls to minimize the potential impact of such vulnerabilities. Additionally, monitoring for unusual file access patterns and implementing least privilege principles for cron job management can help detect and prevent exploitation attempts. Organizations should conduct regular security assessments of their cron management systems to identify similar vulnerabilities that could be exploited in other system components.