CVE-2018-7777 in U.motion Builder
Summary
by MITRE
In Schneider Electric U.motion Builder software versions prior to v1.3.4, malicious clients can upload and cause the smbd server to execute a shared library from a writable share.
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Analysis
by VulDB Data Team • 09/16/2024
The vulnerability identified as CVE-2018-7777 affects Schneider Electric U.motion Builder software versions earlier than v1.3.4, representing a critical security flaw that enables remote code execution through improper file handling mechanisms. This issue specifically targets the smbd server component within the software ecosystem, creating a pathway for attackers to escalate privileges and gain unauthorized control over affected systems. The vulnerability stems from inadequate validation of shared library uploads, allowing malicious actors to exploit writable shares for arbitrary code execution.
The technical flaw manifests through a weakness in the smbd server's file processing capabilities, where the system fails to properly validate or sanitize shared library files uploaded by clients. When a malicious client uploads a shared library to a writable share, the smbd server executes this library without sufficient verification mechanisms, effectively allowing code injection attacks. This behavior violates fundamental security principles of input validation and privilege separation, creating a direct attack vector for remote code execution. The vulnerability is classified under CWE-434, which addresses "Unrestricted Upload of File with Dangerous Type," indicating the improper handling of file uploads that can lead to arbitrary code execution.
The operational impact of CVE-2018-7777 is significant for organizations utilizing Schneider Electric U.motion Builder software, particularly in industrial control environments where system integrity and security are paramount. Attackers can leverage this vulnerability to install backdoors, modify critical system files, or establish persistent access to industrial networks. The threat landscape for such vulnerabilities aligns with ATT&CK technique T1059.007, which covers "Command and Scripting Interpreter: PowerShell," as attackers may use the executed shared libraries to deploy additional malicious tools or establish command and control channels. The vulnerability affects both the availability and confidentiality of industrial systems, potentially leading to operational disruptions and unauthorized data access.
Organizations should immediately implement mitigations including updating to Schneider Electric U.motion Builder version 1.3.4 or later, which contains patches addressing the shared library execution flaw. Network segmentation should be enforced to limit access to affected systems, with proper firewall rules restricting communication to only trusted sources. Additionally, implementing strict access controls on writable shares and disabling unnecessary file sharing capabilities can significantly reduce the attack surface. Security monitoring should be enhanced to detect anomalous file upload activities or unexpected shared library executions, while regular vulnerability assessments should be conducted to identify similar issues in industrial control systems. The remediation process must also include comprehensive testing of the updated software to ensure that the patch does not introduce compatibility issues with existing industrial processes, as outlined in NIST SP 800-40 guidelines for industrial control system security.