CVE-2016-7833 in Dezie
Summary
by MITRE
Cybozu Dezie 8.0.0 to 8.1.1 allows remote attackers to bypass access restrictions to delete an arbitrary DBM (Cybozu Dezie proprietary format) file via unspecified vectors.
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Analysis
by VulDB Data Team • 10/15/2019
The vulnerability identified as CVE-2016-7833 affects Cybozu Dezie versions 8.0.0 through 8.1.1, representing a critical access control flaw that enables remote attackers to bypass authentication mechanisms and delete arbitrary database files in the proprietary DBM format. This issue stems from insufficient input validation and inadequate authorization checks within the application's file management subsystem, allowing unauthorized users to exploit unspecified vectors to manipulate database resources. The vulnerability specifically targets the Cybozu Dezie platform's proprietary database management system, which utilizes the DBM file format for storing structured data. The flaw exists in the application's handling of file deletion operations, where proper access controls are not enforced during the deletion process, creating a pathway for remote exploitation.
The technical implementation of this vulnerability involves the exploitation of weak access control mechanisms within the Dezie application's file management interface. Attackers can leverage unspecified vectors to craft malicious requests that bypass the normal authentication and authorization procedures required to access database files. This typically occurs when the application fails to properly validate user credentials or session tokens before executing destructive operations. The vulnerability's impact is amplified by the fact that it allows for arbitrary file deletion, which can result in complete data loss, system instability, and potential service disruption. The DBM file format used by Cybozu Dezie is proprietary to the platform, making this vulnerability particularly concerning for organizations heavily reliant on the specific database structures and applications built around this technology. The lack of comprehensive input sanitization and validation in the file deletion pathways creates multiple attack surfaces that can be exploited by remote threat actors.
The operational impact of CVE-2016-7833 extends beyond immediate data loss scenarios to encompass broader security implications for affected organizations. Remote attackers can leverage this vulnerability to perform unauthorized database destruction, potentially causing significant business disruption and data integrity issues. The ability to delete arbitrary database files without proper authorization creates a severe risk for organizations that depend on Cybozu Dezie for critical business operations, as it can result in complete loss of structured data and potentially compromise the availability of applications that rely on these databases. The vulnerability's remote exploitability means that attackers do not require physical access to the system or local network privileges to carry out successful attacks. This characteristic makes the vulnerability particularly dangerous in environments where the application is exposed to untrusted networks or where inadequate network segmentation exists between internal and external systems. Organizations may also face regulatory compliance issues if data loss occurs due to this vulnerability, as it represents a failure to maintain proper access controls and data protection mechanisms.
Mitigation strategies for CVE-2016-7833 should focus on immediate patching of affected Cybozu Dezie installations to version 8.1.2 or later, which contains the necessary security fixes to address the access control bypass. Organizations should implement network segmentation to limit exposure of Cybozu Dezie applications to untrusted networks and enforce strict access controls at the network level. Additional protective measures include implementing robust input validation and output encoding for all file operations, establishing comprehensive monitoring and logging of database file access and modification activities, and conducting regular security assessments of the application's file management interfaces. Security controls should also include the implementation of least privilege principles for database access, ensuring that only authorized personnel have the necessary permissions to perform destructive operations. The vulnerability aligns with CWE-284, which addresses improper access control in software systems, and corresponds to attack techniques within the ATT&CK framework related to privilege escalation and data destruction. Organizations should also consider implementing application whitelisting policies and regular security audits to prevent similar vulnerabilities from emerging in other components of their software infrastructure.