CVE-2017-9658 in IntelliVue MX40
Summary
by MITRE
Certain 802.11 network management messages have been determined to invoke wireless access point blacklisting security defenses when not required, which can necessitate intervention by hospital staff to reset the device and reestablish a network connection to the Wi-Fi access point. During this state, the Philips IntelliVue MX40 Version B.06.18 can either connect to an alternative access point within signal range for association to a central monitoring station, or it can remain in local monitoring mode until the device is reset by hospital staff. CVSS v3 base score: 6.5, CVSS vector string: AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Philips has released software update, Version B.06.18, to fix the improper cleanup on thrown exception vulnerability, and implement mitigations to reduce the risk associated with the improper handling of exceptional conditions vulnerability. The software update implements messaging and alarming on the MX40 and at the central monitoring station, when the MX40 disconnects from the access point.
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Analysis
by VulDB Data Team • 02/01/2020
The vulnerability described in CVE-2017-9658 represents a significant security flaw in Philips IntelliVue MX40 patient monitoring devices that operates at the wireless network management layer. This issue specifically affects 802.11 network communication protocols and demonstrates how improper exception handling can create operational disruptions in critical medical environments. The vulnerability stems from the device's failure to properly manage network management messages, leading to unintended blacklisting of wireless access points during routine network operations. This behavior creates a dangerous situation in healthcare settings where continuous patient monitoring is essential, as the device may lose connectivity without proper notification or recovery mechanisms.
The technical flaw manifests when certain 802.11 network management messages trigger security defenses that were designed to protect against malicious activity but are being activated by legitimate network operations. This improper cleanup on thrown exception vulnerability, classified under CWE-248, occurs when the device fails to properly handle exceptional conditions during network communication, leading to a state where the wireless access point becomes temporarily unavailable. The device's response to this condition creates a cascading effect that requires manual intervention from healthcare staff to reset the system and reestablish network connectivity, potentially compromising patient care continuity. The CVSS v3 base score of 6.5 indicates a medium severity vulnerability that can cause significant availability impact, as reflected by the AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H vector.
The operational impact of this vulnerability extends beyond simple network disruption to create critical reliability issues in hospital environments where patient monitoring systems must maintain continuous operation. When the device disconnects from the access point, it can either automatically connect to an alternative access point within signal range or remain in local monitoring mode until manually reset by staff. This dual behavior creates uncertainty in patient monitoring workflows and potentially leaves patients without continuous monitoring if the automatic failover fails. The vulnerability directly impacts the availability aspect of the CIA triad, as demonstrated by the high availability impact score of 8.0 in the CVSS vector. Healthcare facilities must maintain redundant systems and protocols to address such failures, which increases operational complexity and resource allocation requirements.
Philips addressed this vulnerability through a comprehensive software update version B.06.18 that implements proper exception handling mechanisms and enhances security defenses. The update includes messaging and alarming capabilities that notify both the MX40 device and the central monitoring station when disconnections occur, providing operators with immediate awareness of network issues. This mitigation approach aligns with ATT&CK framework techniques related to privilege escalation and defense evasion, as it prevents the improper activation of security mechanisms while maintaining proper communication channels. The implementation of proper exception handling reduces the risk associated with exceptional condition vulnerabilities and ensures that network management messages are processed without triggering unintended security responses. The update also addresses the improper cleanup on thrown exception vulnerability through better resource management and error recovery procedures. This solution demonstrates the importance of robust error handling in medical device security and aligns with industry standards for secure medical device development and maintenance.