CVE-2018-15156 in OpenEMR
Summary
by MITRE
OS command injection occurring in versions of OpenEMR before 5.0.1.4 allows a remote authenticated attacker to execute arbitrary commands by making a crafted request to interface/fax/faxq.php after modifying the "hylafax_server" global variable in interface/super/edit_globals.php.
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Analysis
by VulDB Data Team • 05/02/2023
The vulnerability CVE-2018-15156 represents a critical operating system command injection flaw within the OpenEMR electronic health records system. This vulnerability affects versions prior to 5.0.1.4 and enables remote authenticated attackers to execute arbitrary commands on the underlying system. The flaw manifests through a specific attack vector involving manipulation of the hylafax_server global variable, which is configured in the interface/super/edit_globals.php file. The vulnerability's exploitation requires an authenticated user with sufficient privileges to modify global system settings, making it particularly dangerous in environments where administrative access is compromised or where users have elevated permissions.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within the fax queue processing functionality. When a malicious user modifies the hylafax_server variable and subsequently triggers the faxq.php interface, the system fails to properly escape or validate user-supplied input before incorporating it into system commands. This creates a classic command injection scenario where attacker-controlled data becomes part of the execution context, allowing for arbitrary command execution with the privileges of the web application process. The vulnerability aligns with CWE-77, which specifically addresses command injection flaws in software systems. The attack chain begins with authenticated access to the system followed by modification of global configuration variables, ultimately leading to remote code execution capabilities.
The operational impact of this vulnerability extends beyond simple command execution, as it can result in complete system compromise and data breaches within healthcare environments. Attackers could leverage this vulnerability to escalate privileges, access sensitive patient information, modify or delete critical system files, and potentially establish persistent backdoors within the organization's infrastructure. In healthcare settings, this represents a severe risk to patient privacy and regulatory compliance, particularly concerning HIPAA requirements for protecting protected health information. The vulnerability's remote execution capability means attackers do not need physical access to the system, and the authenticated requirement reduces the attack surface complexity while still maintaining significant risk potential.
Mitigation strategies for CVE-2018-15156 should prioritize immediate patching of affected OpenEMR installations to version 5.0.1.4 or later, which contains the necessary input validation fixes. Organizations should implement network segmentation to limit access to the fax queue functionality and restrict administrative privileges to only essential personnel. Additional protective measures include implementing web application firewalls to monitor for suspicious parameter manipulation patterns, conducting regular security assessments of healthcare applications, and establishing strict access controls for global configuration modification. The vulnerability demonstrates the importance of input validation in healthcare information systems and aligns with ATT&CK technique T1059.001 for command and script injection. Security teams should also consider implementing automated vulnerability scanning tools that can detect similar patterns in other healthcare applications and ensure proper logging and monitoring of configuration changes to detect potential exploitation attempts.