CVE-2016-4036 in Linux
Summary
by MITRE
openSUSE and SUSE Linux Enterprise Server 11 SP 1 use weak permissions for /etc/quagga, which allows local users to obtain sensitive information by reading files in the directory.
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Analysis
by VulDB Data Team • 07/25/2022
The vulnerability identified as CVE-2016-4036 affects openSUSE and SUSE Linux Enterprise Server 11 SP1 systems where the /etc/quagga directory exhibits weak file permissions that expose sensitive configuration data to unauthorized local users. This issue represents a classic privilege escalation and information disclosure vulnerability that undermines the security posture of network infrastructure services running on these platforms. The quagga routing software package typically stores critical network configuration files, routing tables, and authentication credentials within this directory structure, making it a prime target for local attackers seeking to extract confidential information.
The technical flaw stems from improper directory permission settings where the /etc/quagga directory lacks appropriate access controls, allowing local users to read files that should remain restricted to authorized system administrators. This weakness directly violates security principles of least privilege and access control enforcement, creating an avenue for information disclosure attacks. The vulnerability specifically affects systems where the quagga package is installed and configured, with the directory permissions typically set to allow world-readable access instead of restricting access to root or specific administrative groups. This misconfiguration enables any local user to examine routing configurations, authentication details, and other sensitive network infrastructure data that could be leveraged for further attacks or system compromise.
The operational impact of this vulnerability extends beyond simple information disclosure, as the exposed data could include routing protocols configuration, neighbor relationships, authentication keys, and network topology information that adversaries could use for network reconnaissance and advanced persistent threat activities. According to CWE-732, this represents an incorrect permission assignment vulnerability where the system fails to properly restrict access to sensitive information. The exposure of such data could facilitate network mapping, protocol analysis, and potentially enable attackers to craft more sophisticated attacks against the network infrastructure. From an ATT&CK framework perspective, this vulnerability maps to T1083 (File and Directory Discovery) and T1552 (Unsecured Credentials) techniques, as attackers could use the exposed information to identify system components and extract authentication credentials.
Mitigation strategies for CVE-2016-4036 involve immediate remediation of directory permissions to ensure that the /etc/quagga directory and its contents are properly restricted to authorized administrative users only. System administrators should implement restrictive permissions such as chmod 700 for the directory and ensure that all files within contain appropriate access controls. The recommended approach includes setting ownership to root:root and removing world-readable permissions to prevent unauthorized access to sensitive routing configuration data. Additionally, regular security audits should verify that similar permission issues do not exist in other sensitive directories within the system. Organizations should also implement configuration management practices to ensure that permission settings are maintained consistently across all systems and that automated checks can detect and alert on any unauthorized permission changes to critical system directories. The vulnerability highlights the importance of proper privilege management and access control enforcement in maintaining system security posture.