CVE-2016-1196 in Garoon
Summary
by MITRE
Cybozu Garoon 3.x and 4.x before 4.2.1 allows remote authenticated users to bypass intended access restrictions and obtain sensitive Address Book information via an API call, a different vulnerability than CVE-2015-7776.
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Analysis
by VulDB Data Team • 01/31/2019
The vulnerability identified as CVE-2016-1196 affects Cybozu Garoon versions 3.x and 4.x prior to 4.2.1, representing a critical access control flaw that undermines the security posture of enterprise collaboration platforms. This vulnerability specifically targets the Address Book functionality within the Garoon system, which serves as a centralized directory for employee contact information and organizational data. The flaw enables remote authenticated users to circumvent intended access restrictions through improperly validated API calls, potentially exposing sensitive organizational information to unauthorized individuals who possess valid credentials. The vulnerability operates at the application layer and leverages weaknesses in the permission validation mechanisms that should govern access to contact directory information. Unlike CVE-2015-7776 which addressed different access control issues, this vulnerability specifically targets the Address Book API endpoint and represents a distinct class of privilege escalation through improper access control validation. The security implications extend beyond simple information disclosure as the Address Book typically contains sensitive organizational data including employee names, email addresses, phone numbers, department affiliations, and potentially manager hierarchies that could be exploited for social engineering attacks or further compromise attempts.
The technical implementation of this vulnerability stems from insufficient input validation and authorization checks within the API handling logic for Address Book access. When authenticated users make API calls to retrieve or manipulate Address Book entries, the system fails to properly verify whether the requesting user has appropriate permissions for the specific operation being performed. This flaw likely manifests through improper session validation, missing access control lists, or inadequate role-based permission checks that should normally prevent users from accessing data outside their designated scope. The vulnerability can be exploited by an authenticated user who crafts malicious API requests that bypass normal access controls, potentially gaining access to Address Book entries that should be restricted to specific user groups or administrative roles. This type of vulnerability aligns with CWE-285, which addresses improper authorization in software systems, and represents a classic case of insufficient access control validation where the system fails to properly enforce security policies during API interactions. The attack vector requires network access and valid authentication credentials, making it particularly dangerous in environments where credential compromise is possible or where users may have elevated privileges through legitimate business processes.
The operational impact of this vulnerability extends beyond immediate information disclosure to potentially enable broader security compromise within enterprise environments. Organizations relying on Garoon for collaboration and directory services face significant risks when this vulnerability exists, as Address Book information often contains critical business intelligence including organizational structures, communication patterns, and personnel details that could be exploited for targeted attacks. The exposure of employee contact information creates opportunities for phishing campaigns, social engineering attacks, and insider threat scenarios where unauthorized individuals can map organizational relationships and identify potential targets for further exploitation. Additionally, the vulnerability could facilitate privilege escalation attacks where users with limited access attempt to gather information about other users to identify administrative accounts or high-value targets within the organization. From an enterprise security perspective, this vulnerability undermines the principle of least privilege and could lead to cascading security issues if the compromised Address Book information is used to plan more sophisticated attacks. The vulnerability also impacts compliance requirements for organizations subject to data protection regulations, as unauthorized access to employee directory information may constitute regulatory violations.
Organizations should implement immediate mitigations including updating to Garoon version 4.2.1 or later, which contains the necessary patches to address the access control validation issues. Network segmentation and API access controls should be reviewed and strengthened to limit exposure of vulnerable endpoints, while monitoring should be implemented to detect unusual API access patterns that might indicate exploitation attempts. Security teams should conduct comprehensive access control reviews to ensure that Address Book permissions are properly configured and that role-based access controls are functioning as intended. Additionally, organizations should implement principle of least privilege policies for API access, ensuring that users only receive the minimum permissions necessary for their legitimate business functions. The vulnerability highlights the importance of regular security assessments and patch management processes, particularly for collaboration platforms that handle sensitive organizational data. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and credential access, with potential for lateral movement through the acquired contact information. Regular security training for administrators and users should emphasize the importance of maintaining secure authentication practices and monitoring for anomalous access patterns that could indicate exploitation of similar access control vulnerabilities.