CVE-2004-0793 in bsdmainutils
Summary
by MITRE
The calendar program in bsdmainutils 6.0 through 6.0.14 does not drop root privileges when executed with the -a flag, which allows attackers to execute arbitrary commands via a calendar event file.
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Analysis
by VulDB Data Team • 06/22/2018
The vulnerability described in CVE-2004-0793 resides within the calendar program distributed as part of bsdmainutils package version 6.0 through 6.0.14. This issue represents a classic privilege escalation flaw that exploits the failure of the application to properly drop root privileges during execution. The calendar program, when invoked with the -a flag, fails to transition from root user context to a less privileged user context, creating a persistent security risk that can be exploited by malicious actors.
The technical flaw manifests in the program's privilege management mechanism where it maintains root privileges throughout execution even when processing user-supplied calendar event files. This behavior violates fundamental security principles and creates an attack surface where an attacker can manipulate calendar event files to execute arbitrary commands with root privileges. The vulnerability specifically occurs when the calendar program processes event files that contain specially crafted commands, allowing for command injection attacks that leverage the elevated privileges. This issue is categorized under CWE-276, which deals with incorrect permissions for critical resources, and represents a privilege escalation vulnerability that directly impacts system security.
The operational impact of this vulnerability is significant as it allows attackers to gain root access to systems running vulnerable versions of bsdmainutils. Once exploited, the attacker can execute arbitrary commands with the highest system privileges, potentially leading to complete system compromise. The attack vector is relatively straightforward since calendar event files can be easily created or modified by users with appropriate permissions, making this vulnerability particularly dangerous in multi-user environments where calendar functionality is utilized. The vulnerability essentially provides a backdoor mechanism for privilege escalation that bypasses normal access controls and authentication mechanisms.
Mitigation strategies for this vulnerability involve immediate patching of affected systems with updated versions of bsdmainutils that properly implement privilege dropping functionality. System administrators should also implement strict file permission controls on calendar event files and monitor for unauthorized modifications to calendar-related resources. Additionally, the principle of least privilege should be enforced by ensuring that the calendar program does not run with root privileges when possible. Organizations should consider implementing security monitoring solutions that can detect anomalous command execution patterns and privilege escalation attempts. The remediation process should also include reviewing and updating system configurations to ensure that no other applications exhibit similar privilege management flaws, aligning with ATT&CK technique T1068 which addresses local privilege escalation through improper privilege handling. This vulnerability highlights the critical importance of proper privilege management in system utilities and demonstrates how seemingly innocuous programs can serve as entry points for sophisticated attacks.