CVE-2016-4947 in HUE
Summary
by MITRE
Cloudera HUE 3.9.0 and earlier allows remote attackers to enumerate user accounts via a request to desktop/api/users/autocomplete.
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Analysis
by VulDB Data Team • 09/04/2020
Cloudera HUE represents a web-based platform for data analysis and management that provides a user-friendly interface for interacting with big data technologies. The vulnerability identified as CVE-2016-4947 affects versions 3.9.0 and earlier, specifically within the desktop/api/users/autocomplete endpoint. This issue constitutes a critical information disclosure vulnerability that enables unauthorized remote attackers to systematically discover valid user accounts within the system. The flaw arises from insufficient input validation and access control mechanisms within the user enumeration API endpoint, which was designed to provide autocomplete functionality for user names but inadvertently exposed the complete user directory to any authenticated or unauthenticated attacker.
The technical implementation of this vulnerability stems from the lack of proper authorization checks on the autocomplete endpoint. When an attacker sends a request to desktop/api/users/autocomplete, the system responds with a list of all valid user accounts without requiring appropriate authentication credentials or access permissions. This behavior violates fundamental security principles of least privilege and access control, as the endpoint should only return user information to authorized users with legitimate business requirements. The vulnerability can be exploited through simple http requests that leverage the autocomplete functionality, making it particularly dangerous as it requires minimal technical expertise to discover and exploit. According to CWE-200, this represents an information disclosure vulnerability where sensitive data about system users is exposed to unauthorized parties.
The operational impact of this vulnerability extends beyond simple user enumeration, as it provides attackers with valuable intelligence for subsequent attack phases. Once an attacker has discovered valid user accounts, they can proceed with targeted credential guessing attacks, password spraying, or social engineering campaigns. The exposure of user accounts can also facilitate privilege escalation attempts, particularly if the system employs weak password policies or shared credentials. This vulnerability directly aligns with ATT&CK technique T1078 which covers legitimate credentials and T1566 which covers credential access through various methods. The impact is particularly severe in enterprise environments where Cloudera HUE serves as a central platform for data access, as it can lead to unauthorized data access, potential data breaches, and compromise of sensitive business information. Organizations may face regulatory compliance violations if user data is exposed, and the vulnerability can significantly weaken overall security posture.
Mitigation strategies for CVE-2016-4947 should focus on implementing proper access controls and input validation for the affected endpoint. Organizations should immediately upgrade to Cloudera HUE versions that address this vulnerability, as the issue was resolved in subsequent releases through proper authorization checks and rate limiting mechanisms. Network-level controls such as firewall rules can be implemented to restrict access to the vulnerable endpoint, though this approach is less secure than proper code-level fixes. The implementation of authentication requirements for the autocomplete endpoint ensures that only authorized users can access user enumeration functionality. Additionally, organizations should implement monitoring and alerting for unusual patterns of user enumeration requests, which can help detect potential exploitation attempts. According to NIST SP 800-53 security controls, this vulnerability requires implementation of access control mechanisms and audit logging to prevent unauthorized access. Regular security assessments should be conducted to identify similar information disclosure vulnerabilities in other system components, as this type of flaw often indicates broader security configuration issues within the application.