CVE-2018-4042 in CleanMyMac X
Summary
by MITRE
An exploitable privilege escalation vulnerability exists in the helper service of Clean My Mac X, version 4.04, due to improper input validation. An attacker with local access could exploit this vulnerability to modify the file system as root.
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Analysis
by VulDB Data Team • 06/26/2023
The vulnerability identified as CVE-2018-4042 represents a critical privilege escalation flaw within the Clean My Mac X software suite, specifically affecting version 4.04. This issue resides within the helper service component of the application, which operates with elevated privileges to perform system maintenance tasks. The vulnerability stems from inadequate input validation mechanisms that fail to properly sanitize or verify user-supplied data before processing. The helper service, designed to execute administrative functions on behalf of the application, inadvertently accepts malformed or malicious inputs that can be leveraged to bypass normal access controls. This flaw creates a dangerous attack surface where local adversaries can exploit the service to gain root-level privileges and subsequently modify any file within the system filesystem.
The technical exploitation of this vulnerability occurs through the helper service's failure to validate input parameters passed to system functions. When the helper service processes user requests, it does not adequately check the integrity or legitimacy of the input data, allowing attackers to inject malicious parameters that manipulate the service's behavior. This improper input validation aligns with CWE-20, which specifically addresses "Improper Input Validation" as a fundamental security weakness. The vulnerability enables an attacker to craft specific inputs that cause the helper service to execute unintended system commands with root privileges, effectively allowing full system compromise. The flaw essentially creates a pathway for local privilege escalation where an unprivileged user can leverage the helper service to perform administrative actions that should normally be restricted to root users.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the security model of the Clean My Mac X application and the underlying operating system. Once exploited, attackers can modify critical system files, install malicious software, alter system configurations, or even establish persistent backdoors within the compromised system. This vulnerability directly violates the principle of least privilege and creates a persistent threat vector that remains active as long as the vulnerable application is installed. The impact is particularly severe because the helper service typically runs with elevated permissions to perform legitimate system cleanup tasks, making it a prime target for exploitation. From an attacker's perspective, this vulnerability represents a high-value target as it provides a reliable method for achieving root access without requiring additional attack vectors or complex exploitation techniques.
Mitigation strategies for CVE-2018-4042 should focus on immediate remediation through official software updates provided by the vendor, as the vulnerability exists within a specific version of the application. System administrators should ensure that all instances of Clean My Mac X are updated to versions that address the input validation issues within the helper service. Additionally, organizations should implement strict application whitelisting policies to prevent unauthorized helper services from executing on systems. The remediation process should include verification that the helper service properly validates all inputs and that appropriate access controls are enforced. Security monitoring should be enhanced to detect unusual activity from the helper service, particularly when it attempts to modify system files or execute commands with elevated privileges. Organizations should also consider implementing additional security measures such as macOS security frameworks, sandboxing policies, and regular security audits to prevent similar vulnerabilities from emerging in other applications. This vulnerability demonstrates the critical importance of proper input validation in privileged code and serves as a reminder that helper services and background processes require rigorous security testing and validation to prevent privilege escalation attacks.