CVE-2018-14533 in iopsys
Summary
by MITRE
read_tmp and write_tmp in Inteno IOPSYS allow attackers to gain privileges after writing to /tmp/etc/smb.conf because /var is a symlink to /tmp.
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Analysis
by VulDB Data Team • 12/04/2024
This vulnerability exists within the Inteno IOPSYS operating system where the read_tmp and write_tmp functions fail to properly validate file operations targeting the /tmp/etc/smb.conf file. The core issue stems from the symbolic link relationship between /var and /tmp directories, creating a privilege escalation pathway that attackers can exploit to execute arbitrary code with elevated privileges. The flaw allows malicious actors to manipulate configuration files in a way that bypasses normal access controls and security boundaries.
The technical implementation of this vulnerability leverages the fact that /var is symlinked to /tmp, enabling attackers to write to sensitive configuration files in /tmp while the system interprets these writes as occurring in the /var directory. This creates a scenario where privilege escalation becomes possible through manipulation of the smb.conf file, which typically requires administrative privileges to modify. The vulnerability specifically affects the handling of temporary files and configuration management within the IOPSYS framework, making it particularly dangerous in networked environments where these services are exposed.
Operational impact of CVE-2018-14533 extends beyond simple privilege escalation to encompass complete system compromise potential. Attackers can leverage this vulnerability to modify critical network configuration files, inject malicious code, or establish persistent backdoors within the device. The vulnerability affects devices running Inteno IOPSYS firmware, which are commonly found in consumer and enterprise networking equipment, making it a significant concern for network administrators managing these systems. The low complexity required to exploit this vulnerability means that even less sophisticated attackers can potentially gain unauthorized access to network infrastructure.
The vulnerability aligns with CWE-276, which addresses improper privileges, and represents a classic case of insecure temporary file handling that enables privilege escalation attacks. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques where adversaries leverage system configuration weaknesses to gain elevated access. The attack surface is particularly concerning given that many networking devices running IOPSYS remain unpatched in production environments, creating widespread exposure across various network infrastructures.
Mitigation strategies should include immediate firmware updates from Inteno to address the symlink handling issue, proper directory permissions configuration to prevent unauthorized writes to critical system locations, and network segmentation to limit access to vulnerable devices. System administrators should also implement monitoring for unusual file modification patterns in temporary directories and establish regular security audits of network infrastructure. Additionally, the vulnerability highlights the importance of proper symbolic link validation in embedded systems and the need for comprehensive security testing of file operation handling within firmware components.