CVE-2016-4870 in Cybozu Office
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in "Schedule" function in Cybozu Office 9.0.0 through 10.4.0.
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Analysis
by VulDB Data Team • 08/31/2020
The vulnerability CVE-2016-4870 represents a cross-site scripting flaw discovered in the scheduling functionality of Cybozu Office versions 9.0.0 through 10.4.0. This issue affects a widely used business collaboration platform that provides integrated office applications including calendar scheduling, document management, and workflow automation. The vulnerability specifically resides within the schedule function's handling of user input, creating an avenue for malicious actors to inject harmful scripts into the application's web interface. The affected system operates as a web-based corporate collaboration environment where users create and manage scheduling events, making this particular flaw particularly concerning for enterprise security.
The technical implementation of this XSS vulnerability stems from insufficient input validation and output encoding within the scheduling component of Cybozu Office. When users create or modify schedule entries, the application fails to properly sanitize user-supplied data before rendering it back to the browser interface. This allows attackers to inject malicious javascript code through schedule titles, descriptions, or other editable fields. The vulnerability is classified as a reflected XSS issue where malicious payloads are executed when other users view the affected schedule entries. The flaw exists at the application layer where user input flows directly into HTML output without proper sanitization mechanisms, violating fundamental web security principles. This type of vulnerability aligns with CWE-79 which specifically addresses cross-site scripting weaknesses in web applications.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it can enable attackers to perform session hijacking, redirect users to malicious sites, or execute arbitrary code within the context of the victim's browser. In enterprise environments where Cybozu Office is used for critical business operations, this vulnerability could facilitate unauthorized access to sensitive scheduling data, including confidential meeting information, resource allocations, and business planning details. Attackers could leverage this flaw to establish persistent access points within corporate networks, particularly if the application is used for internal communications and scheduling of sensitive business activities. The vulnerability affects the availability and integrity of the scheduling system, potentially disrupting business operations and compromising the confidentiality of calendar data.
Organizations utilizing affected Cybozu Office versions should prioritize immediate remediation through official vendor patches or updates. The recommended mitigation strategy involves implementing proper input validation and output encoding mechanisms throughout the application's web interface, particularly in the scheduling component. Security teams should also consider implementing content security policies to limit script execution and deploy web application firewalls to detect and block malicious payloads. Additionally, regular security assessments should be conducted to identify similar vulnerabilities in other components of the Cybozu Office suite. Organizations may also need to implement user education programs to raise awareness about recognizing potential XSS attack vectors and avoid clicking on suspicious schedule entries. The remediation process should include thorough testing to ensure that the patch does not introduce regressions in legitimate scheduling functionality, while also verifying that all input fields properly sanitize user data before processing. This vulnerability demonstrates the critical importance of maintaining up-to-date security patches in enterprise collaboration platforms and highlights the potential for seemingly minor functionality flaws to create significant security risks.