CVE-2018-7776 in U.motion Builder
Summary
by MITRE
The vulnerability is due to insufficient handling of update_file request parameter on update_module.php in Schneider Electric U.motion Builder software versions prior to v1.3.4. A remote, authenticated attacker can exploit this vulnerability by sending a crafted request to the target server.
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Analysis
by VulDB Data Team • 02/24/2020
The vulnerability identified as CVE-2018-7776 resides within Schneider Electric U.motion Builder software, specifically in the update_module.php component where inadequate validation occurs for the update_file request parameter. This flaw represents a critical security weakness that allows authenticated remote attackers to manipulate the software's update mechanism and potentially execute arbitrary code on the affected system. The vulnerability stems from insufficient input sanitization and parameter handling, creating an attack surface that can be exploited by malicious actors who have already gained legitimate access credentials to the system.
The technical implementation of this vulnerability manifests through improper validation of the update_file parameter which is processed during module update operations. When a crafted request is sent to the update_module.php endpoint, the software fails to adequately sanitize or restrict the file path or content being processed, allowing attackers to specify arbitrary files for update operations. This insufficient handling creates a path traversal or file inclusion vulnerability that can be leveraged to overwrite critical system files or inject malicious code into the target environment. The vulnerability operates at the application layer and requires authentication to exploit, making it particularly dangerous as it can be used to escalate privileges or gain unauthorized access to system resources.
From an operational perspective, this vulnerability poses significant risks to industrial control systems and building automation environments where Schneider Electric U.motion Builder is deployed. The authenticated nature of the exploit means that attackers must first obtain valid credentials, but once inside the system, they can leverage this vulnerability to compromise the integrity of the software update process. The impact extends beyond simple code execution as attackers can potentially modify core modules, disable security features, or establish persistent backdoors within the industrial control environment. This vulnerability particularly affects environments where the software is used for critical infrastructure management, as it can lead to operational disruptions, data corruption, or unauthorized control of building systems.
Organizations should implement immediate mitigations including updating to Schneider Electric U.motion Builder version 1.3.4 or later, which contains the necessary patches to address the insufficient parameter handling. Network segmentation and access controls should be enforced to limit exposure of the update endpoints to only authorized personnel. Additionally, implementing robust monitoring solutions that can detect anomalous update requests or file modifications can provide early warning of exploitation attempts. The vulnerability aligns with CWE-22 Path Traversal and CWE-74 Injection flaws, and maps to ATT&CK technique T1059 Command and Scripting Interpreter for executing malicious code, while also representing a privilege escalation vector through T1068 Local Privilege Escalation. Regular security assessments and vulnerability scanning should be conducted to identify similar parameter handling issues across other components of the industrial control system infrastructure.