CVE-2018-11053 in iDRAC Service Module
Summary
by MITRE
Dell EMC iDRAC Service Module for all supported Linux and XenServer versions v3.0.1, v3.0.2, v3.1.0, v3.2.0, when started, changes the default file permission of the hosts file of the host operating system (/etc/hosts) to world writable. A malicious low privileged operating system user or process could modify the host file and potentially redirect traffic from the intended destination to sites hosting malicious or unwanted content.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 02/22/2020
The vulnerability identified as CVE-2018-11053 represents a critical privilege escalation and traffic interception flaw within Dell EMC iDRAC Service Module versions 3.0.1 through 3.2.0 across supported Linux and XenServer environments. This issue stems from improper privilege management during service initialization, where the iDRAC module modifies system-level file permissions without adequate security controls. The hosts file, which serves as a crucial local DNS resolution mechanism mapping hostnames to IP addresses, becomes globally writable during the service startup process, creating a persistent security weakness that can be exploited by any low-privileged user or process on the system.
The technical flaw manifests through the service module's failure to properly implement access control mechanisms when modifying the /etc/hosts file permissions. This misconfiguration allows the service to set world-writable permissions on a system-critical file that should typically be restricted to root-level modifications only. The vulnerability directly maps to CWE-732: Incorrect Permission Assignment for Critical Resource, which specifically addresses cases where critical system resources receive overly permissive access controls. The flaw exists at the operating system interaction level where privilege separation principles are violated, as the service module should not be able to alter system-level file permissions without proper authorization and validation.
From an operational impact perspective, this vulnerability enables attackers to perform man-in-the-middle attacks by redirecting network traffic to malicious destinations. A malicious user with minimal privileges can modify the hosts file to redirect traffic intended for legitimate services to attacker-controlled systems, potentially compromising sensitive data transmission, enabling credential harvesting, or facilitating phishing attacks. The persistent nature of this vulnerability means that once exploited, the redirection remains active until the system is rebooted or the hosts file is manually corrected, creating an ongoing threat vector that can be leveraged for extended periods without detection. This vulnerability particularly affects enterprise environments where iDRAC modules are commonly deployed for remote system management, as it undermines the security assumptions of the underlying operating system.
The exploitation of this vulnerability aligns with several tactics described in the MITRE ATT&CK framework, specifically covering techniques related to privilege escalation and persistence. The attack pattern follows ATT&CK technique T1068: Exploitation for Privilege Escalation, where attackers leverage system misconfigurations to gain elevated privileges. Additionally, the vulnerability supports T1566: Phishing for Information and T1071.004: Application Layer Protocol: DNS, as attackers can redirect traffic to malicious domains for data exfiltration or malicious payload delivery. Organizations should implement immediate mitigations including updating to patched versions of the iDRAC Service Module, implementing file integrity monitoring for the /etc/hosts file, and conducting privileged access reviews to ensure that only authorized users can modify critical system files. The vulnerability underscores the importance of proper privilege separation and access control implementation in system services, particularly those with elevated capabilities during system initialization phases.