CVE-2016-4529 in SoMachine HVAC
Summary
by MITRE
An unspecified ActiveX control in Schneider Electric SoMachine HVAC Programming Software for M171/M172 Controllers before 2.1.0 allows remote attackers to execute arbitrary code via unknown vectors, related to the INTERFACESAFE_FOR_UNTRUSTED_CALLER (aka safe for scripting) flag.
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Analysis
by VulDB Data Team • 10/01/2024
The vulnerability identified as CVE-2016-4529 represents a critical security flaw within Schneider Electric SoMachine HVAC Programming Software version 2.1.0 and earlier, specifically affecting M171/M172 Controllers. This issue stems from an unspecified ActiveX control that has been improperly configured with the INTERFACESAFE_FOR_UNTRUSTED_CALLER flag, commonly referred to as safe for scripting. The ActiveX control mechanism serves as a component model that enables software components to interact across different applications and platforms, making it a prime target for exploitation in attack scenarios.
The technical nature of this vulnerability lies in the improper implementation of security boundaries within the ActiveX control's interface configuration. When the INTERFACESAFE_FOR_UNTRUSTED_CALLER flag is set, it indicates that the control should be considered safe for use in untrusted contexts, meaning it can be executed by potentially malicious code without the normal security restrictions typically applied to such components. This misconfiguration allows attackers to bypass the intended security model of the software, creating an opportunity for remote code execution attacks. The vulnerability operates through unknown vectors that are not explicitly detailed, suggesting that the attack surface may involve multiple potential pathways through which an attacker could leverage this misconfiguration.
The operational impact of this vulnerability extends beyond simple code execution, as it fundamentally compromises the security model of the programming software environment. Attackers could potentially install malicious code on systems running the affected software, leading to complete system compromise and potential lateral movement within network environments. The vulnerability affects industrial control systems specifically designed for HVAC programming, which may be deployed in critical infrastructure environments where system integrity is paramount. The remote execution capability means that attackers need not have physical access to the systems, making this vulnerability particularly dangerous in operational technology environments where security is often less stringent than in traditional IT environments.
This vulnerability aligns with CWE-749, which addresses "Expose of Functionality to Unintended Actors," and reflects the broader category of insecure object handling in ActiveX controls. The flaw demonstrates poor security implementation practices that violate fundamental principles of secure coding and privilege separation. From an ATT&CK perspective, this vulnerability could be leveraged for initial access and execution phases, potentially supporting techniques such as exploitation of remote services and command and control communication. Organizations implementing industrial control systems must consider this vulnerability as part of their overall security posture, particularly when assessing the risks associated with legacy software components that may not receive regular security updates. The lack of specific details regarding the attack vectors suggests that multiple exploitation pathways may exist, requiring comprehensive security assessments and potentially multiple mitigation strategies.
Mitigation efforts should focus on immediate software updates to version 2.1.0 or later, which presumably address the misconfigured ActiveX control. Additionally, network segmentation and access controls should be implemented to limit exposure of affected systems to untrusted networks. Security monitoring should be enhanced to detect potential exploitation attempts, and regular vulnerability assessments should be conducted to identify similar misconfigurations in other industrial control system components. The vulnerability underscores the importance of maintaining up-to-date industrial control system software and implementing robust security controls in operational technology environments.