CVE-2018-18976 in Contour NEXT ONE App
Summary
by MITRE
An issue was discovered in the Ascensia Contour NEXT ONE application for iOS and Android before 2019-01-15. An attacker may retrieve encrypted medical information of any user of the Ascensia cloud platform by performing Direct Object References with a series of user ID values. (This information can be decrypted through a different vulnerability.)
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Analysis
by VulDB Data Team • 09/12/2023
The vulnerability identified as CVE-2018-18976 represents a critical security flaw in the Ascensia Contour NEXT ONE mobile health application ecosystem that affected both iOS and Android platforms prior to the January 15, 2019 update. This vulnerability specifically targets the application's cloud-based data access mechanisms and demonstrates a fundamental weakness in the application's authorization and authentication frameworks. The flaw enables unauthorized data access through what is known as direct object reference exploitation, where an attacker can manipulate object references to gain access to data they should not be authorized to view, fundamentally undermining the application's security model and user privacy protections.
The technical implementation of this vulnerability stems from improper input validation and insufficient access control mechanisms within the application's cloud communication protocols. When the application interacts with the Ascensia cloud platform, it relies on user identifiers to reference specific patient records and medical data. The vulnerability occurs because the application does not adequately validate these identifiers before processing requests, allowing an attacker to sequentially test various user ID values to discover valid references to other users' medical information. This type of vulnerability falls under the CWE-284 category of "Improper Access Control" and aligns with the ATT&CK technique T1078.004 for Valid Accounts, as it exploits the legitimate access patterns of the system without requiring actual authentication credentials.
The operational impact of this vulnerability extends beyond simple data exposure, as it creates a significant risk for patient privacy and healthcare data protection. Medical information retrieved through this vulnerability could include sensitive patient data such as glucose readings, medication histories, treatment plans, and other confidential health records that are typically protected under healthcare privacy regulations including HIPAA in the United States. The fact that the retrieved data is encrypted but can be decrypted through a separate vulnerability creates a particularly dangerous scenario where attackers can potentially access comprehensive patient medical histories. This vulnerability represents a serious breach of the principle of least privilege and demonstrates how insufficient access control can lead to massive data exposure across an entire user base of a healthcare application.
Mitigation strategies for this vulnerability should focus on implementing proper input validation, enforcing robust access control mechanisms, and implementing proper authentication checks before any data access operations occur. The application should implement proper user session management and ensure that all object references are validated against the authenticated user's permissions before data retrieval. Additionally, the system should implement rate limiting and monitoring to detect unusual access patterns that might indicate exploitation attempts. Organizations should also consider implementing automated vulnerability scanning and regular penetration testing to identify similar direct object reference vulnerabilities in their applications. The remediation process requires comprehensive code review and the implementation of proper access control frameworks that align with industry standards for healthcare application security. This vulnerability serves as a critical reminder of the importance of proper access control implementation in healthcare applications where patient privacy is paramount and regulatory compliance requirements are stringent.