CVE-2021-29005 in rConfig
Summary
by MITRE • 10/11/2021
Insecure permission of chmod command on rConfig server 3.9.6 exists. After installing rConfig apache user may execute chmod as root without password which may let an attacker with low privilege to gain root access on server.
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Analysis
by VulDB Data Team • 10/14/2021
The vulnerability identified as CVE-2021-29005 represents a critical privilege escalation flaw within the rConfig server version 3.9.6, specifically exploiting insecure permissions associated with the chmod command execution. This vulnerability stems from improper configuration of sudo permissions that allow a low-privileged apache user to execute the chmod command with root privileges without requiring authentication. The flaw exists within the server's privilege management system where the sudoers configuration fails to properly restrict command execution capabilities, creating an attack vector that directly undermines the principle of least privilege.
The technical implementation of this vulnerability involves the manipulation of file permissions through the chmod command, which when executed with elevated privileges can modify critical system files and directories. An attacker exploiting this vulnerability can leverage the apache user's ability to execute chmod as root to modify system binaries, configuration files, or even create backdoor accounts that persist across system reboots. This represents a classic privilege escalation attack pattern where initial access through a web application is leveraged to gain root-level system control, enabling full compromise of the affected server.
The operational impact of CVE-2021-29005 extends beyond simple unauthorized access, as it provides attackers with complete system control capabilities. Once an attacker achieves root access through this vulnerability, they can establish persistent backdoors, modify system logs to cover their tracks, install malicious software, and exfiltrate sensitive data from the compromised server. The vulnerability's exploitation directly violates security principles defined in the Common Weakness Enumeration framework under CWE-276, which addresses incorrect permissions for critical resources, and aligns with the MITRE ATT&CK framework's privilege escalation techniques where adversaries leverage insecure configurations to gain elevated system privileges.
Security remediation for this vulnerability requires immediate implementation of proper sudoers configuration restrictions to prevent the apache user from executing chmod commands with root privileges. System administrators must review and tighten the sudoers file to ensure that only authorized users and specific commands can execute with elevated privileges. Additionally, implementing proper access controls, regular security audits, and monitoring for unauthorized privilege escalation attempts should be part of the comprehensive mitigation strategy. The vulnerability highlights the importance of principle of least privilege enforcement and proper privilege management, as outlined in various cybersecurity frameworks including NIST SP 800-53 and ISO 27001 standards for access control and system security.