CVE-2016-4865 in Cybozu Office
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the "Customapp" function in Cybozu Office 9.0.0 through 10.4.0.
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Analysis
by VulDB Data Team • 08/31/2020
The CVE-2016-4865 vulnerability represents a critical cross-site scripting flaw discovered in Cybozu Office versions 9.0.0 through 10.4.0, specifically within the Customapp function. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is a fundamental web application security weakness that allows attackers to inject malicious scripts into web pages viewed by other users. The affected Cybozu Office platform is widely used for enterprise collaboration and document management, making this vulnerability particularly concerning for organizations relying on its functionality.
The technical flaw manifests in how the Customapp function processes user input without proper sanitization or encoding mechanisms. When users interact with the application's custom application features, malicious payloads can be injected through parameters or input fields that are subsequently rendered in web pages without adequate security controls. This allows attackers to execute arbitrary JavaScript code within the context of other users' browsers, potentially leading to session hijacking, credential theft, or data exfiltration. The vulnerability is particularly dangerous because it operates at the application layer where user interactions are processed, making it difficult to distinguish between legitimate and malicious input.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable sophisticated attack vectors that compromise entire enterprise environments. Attackers can leverage this XSS flaw to steal session cookies, redirect users to malicious websites, or inject malicious content that persists within the application. Organizations using Cybozu Office in their workflow may experience unauthorized access to sensitive business data, disruption of services, and potential compliance violations. The vulnerability affects multiple versions of the platform, indicating a widespread exposure that requires immediate attention across affected deployments. Security teams must consider the broader implications for their network security posture, as this vulnerability can serve as a stepping stone for more advanced persistent threats.
Mitigation strategies for CVE-2016-4865 should focus on immediate patching of affected Cybozu Office versions, with the implementation of proper input validation and output encoding mechanisms. Organizations should deploy web application firewalls to detect and block malicious payloads, while also implementing content security policies to prevent script execution. Regular security assessments and code reviews should be conducted to identify similar vulnerabilities in custom applications, with adherence to secure coding practices that prevent XSS attacks through proper sanitization of user inputs. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1566.001 for spearphishing attachments, highlighting the need for comprehensive defensive measures that address both application-level and network-level protections.