CVE-2018-0566 in Office
Summary
by MITRE
Cybozu Office 10.0.0 to 10.8.0 allows authenticated attackers to bypass authentication to obtain the schedules without access privilege via unspecified vectors.
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Analysis
by VulDB Data Team • 02/21/2020
The vulnerability identified as CVE-2018-0566 affects Cybozu Office versions 10.0.0 through 10.8.0, representing a critical authentication bypass flaw that enables authenticated attackers to access sensitive schedule information without proper authorization. This issue resides within the application's access control mechanisms, specifically targeting the scheduling functionality that should be protected by appropriate privilege checks. The vulnerability's impact extends beyond simple information disclosure as it represents a fundamental failure in the application's security model where legitimate authentication does not guarantee appropriate authorization levels.
The technical nature of this vulnerability demonstrates a failure in the application's privilege validation system where the authentication process does not adequately verify user permissions before granting access to schedule data. Attackers who have gained initial authenticated access can exploit unspecified vectors within the application's internal logic to circumvent normal access controls and retrieve schedule information that should be restricted based on user roles or permissions. This type of vulnerability typically stems from improper input validation, inadequate session management, or flawed authorization logic that fails to properly enforce access control policies. The issue falls under the category of inadequate authorization controls as classified by CWE-285, which specifically addresses situations where applications fail to properly validate user permissions before granting access to protected resources.
From an operational perspective, this vulnerability creates significant risk for organizations using Cybozu Office as it allows unauthorized access to sensitive schedule information that may contain confidential business data, personal employee information, or strategic planning details. The fact that attackers need only authenticated access to exploit this vulnerability means that even users with basic privileges can potentially access restricted schedule data, making this particularly dangerous in environments where schedule information might contain proprietary details, meeting agendas, or project timelines. The attack vector suggests that the application's internal API or data access methods may not properly validate the requesting user's authorization level before returning schedule information, creating a path for privilege escalation through information disclosure.
The mitigation strategy for CVE-2018-0566 should prioritize immediate patching of affected Cybozu Office installations to the latest available version that addresses this authentication bypass vulnerability. Organizations should also implement additional monitoring of authentication and access logs to detect potential exploitation attempts, particularly around schedule access patterns. Network segmentation and principle of least privilege should be enforced to limit the potential impact of any successful exploitation. Security teams should conduct thorough access control reviews to ensure that all authenticated users have appropriate authorization levels and that schedule data access is properly restricted based on user roles. This vulnerability aligns with ATT&CK technique T1078 which covers legitimate credentials and privilege escalation, as attackers can leverage their authenticated sessions to gain access to resources they should not normally be able to reach, demonstrating the importance of proper authorization controls in maintaining application security boundaries.