CVE-2016-10089 in Nagios
Summary
by MITRE
Nagios 4.2.4 and earlier allows local users to gain root privileges via a hard link attack on the Nagios init script file, related to CVE-2016-8641.
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Analysis
by VulDB Data Team • 08/14/2020
This vulnerability affects Nagios versions 4.2.4 and earlier, presenting a critical privilege escalation vector through a hard link attack against the Nagios init script. The flaw exploits the insecure handling of temporary files during the service startup process, specifically targeting the init script that runs with root privileges. Attackers can create symbolic links to manipulate the execution flow and gain elevated system access. The vulnerability stems from inadequate file permission checks and improper handling of file system operations within the service initialization routine. This type of attack falls under the category of privilege escalation attacks that leverage insecure file handling patterns, aligning with CWE-377 and CWE-378 which address insecure temporary file creation and improper file permissions respectively.
The technical implementation involves exploiting a race condition or insecure file handling mechanism where the Nagios init script creates temporary files or modifies existing files without proper security checks. When the service starts, it processes these files in a manner that allows local users to manipulate the file system through hard links, effectively replacing or modifying critical system components. The attack requires local access to the system but can be executed by unprivileged users who can create symbolic links and manipulate file paths. This vulnerability is particularly concerning because it can be exploited to gain root privileges, which would allow attackers to fully compromise the system and execute arbitrary code with the highest possible privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can lead to complete system compromise and persistent access. Once root privileges are obtained, attackers can install backdoors, modify system configurations, steal sensitive data, or establish persistent footholds within the network. The vulnerability affects systems where Nagios is installed with default configurations and where local users have the ability to create symbolic links. Organizations running affected Nagios versions are at risk of unauthorized privilege escalation, potentially leading to data breaches, system corruption, or further lateral movement within the network infrastructure. The attack vector is particularly dangerous in environments where Nagios is used for critical system monitoring, as compromising the service can affect overall system security posture.
Mitigation strategies should focus on immediate patching of affected Nagios versions to 4.2.5 or later, which contain fixes for the hard link attack vulnerability. System administrators should also implement proper file permission controls and audit the Nagios init script for insecure file handling patterns. Additional protective measures include monitoring for unauthorized file system modifications, implementing proper file system integrity checks, and ensuring that Nagios service accounts run with minimal required privileges. The vulnerability demonstrates the importance of secure coding practices and proper file system handling, particularly when dealing with services that execute with elevated privileges. Organizations should also consider implementing the principle of least privilege and regularly audit their monitoring systems for similar vulnerabilities that could be exploited for privilege escalation. This case highlights the need for continuous security assessments and proper input validation in system initialization processes, aligning with ATT&CK technique T1068 which covers privilege escalation through local exploitation of system vulnerabilities.