CVE-2015-7798 in Office
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Cybozu Office 9.0.0 through 10.3.0 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors, a different vulnerability than CVE-2015-7795, CVE-2015-7796, CVE-2015-7797, CVE-2016-1149, and CVE-2016-1150.
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Analysis
by VulDB Data Team • 07/30/2018
The CVE-2015-7798 vulnerability represents a critical cross-site scripting flaw discovered in Cybozu Office software versions 9.0.0 through 10.3.0. This vulnerability falls under the broader category of web application security flaws that enable malicious actors to execute arbitrary scripts within the context of a user's browser session. The vulnerability is particularly concerning as it affects a widely used enterprise collaboration platform that serves as a central hub for business communications and document management. Unlike related vulnerabilities such as CVE-2015-7795 through CVE-2016-1150 which may have different attack vectors or scopes, this specific flaw operates through unspecified vectors that make it particularly challenging to predict and defend against. The vulnerability's presence in multiple versions of the software indicates a fundamental flaw in the application's input validation and output encoding mechanisms that persisted across several releases.
The technical implementation of this XSS vulnerability stems from insufficient sanitization of user-supplied input data within the Cybozu Office application framework. Attackers can exploit this weakness by crafting malicious payloads that are then executed when other users view the affected content. The unspecified vectors suggest that the vulnerability could be triggered through various entry points within the application, potentially including form fields, URL parameters, or even file upload mechanisms. This broad attack surface makes the vulnerability particularly dangerous as defenders must account for multiple potential exploitation paths. The flaw likely resides in how the application processes and renders user-generated content without proper context-aware encoding or validation, allowing malicious scripts to be injected and subsequently executed in the browser context of unsuspecting users. This type of vulnerability directly maps to CWE-79 which specifically addresses Cross-site Scripting flaws in web applications.
The operational impact of CVE-2015-7798 extends far beyond simple script execution, as it provides attackers with the capability to perform session hijacking, steal sensitive information, redirect users to malicious websites, or even execute more sophisticated attacks such as credential theft. When compromised users interact with the vulnerable application, their browser sessions become vulnerable to manipulation by the attacker, potentially leading to complete account takeover. The business implications are severe, as Cybozu Office serves as a critical communication and collaboration platform for enterprises, making successful exploitation a significant threat to organizational security. Attackers could leverage this vulnerability to access confidential business data, manipulate documents, or use stolen sessions to perform unauthorized actions within the enterprise environment. The vulnerability also enables the execution of persistent attacks that could remain undetected for extended periods, particularly if the malicious payloads are designed to establish backdoors or exfiltrate data over time.
Organizations affected by this vulnerability should implement immediate remediation strategies focusing on the application-level fixes and defensive measures. The primary mitigation involves updating to the latest available version of Cybozu Office where the vulnerability has been patched, as vendors typically address such flaws in subsequent releases. Additionally, implementing comprehensive input validation and output encoding mechanisms can help prevent similar vulnerabilities from persisting in other applications. Security teams should deploy web application firewalls that can detect and block suspicious script injection attempts, while also establishing robust monitoring protocols to identify potential exploitation attempts. Network segmentation and privilege separation can help limit the potential damage if exploitation occurs, ensuring that even if one user account is compromised, the attacker cannot easily move laterally within the network. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other applications within the enterprise ecosystem, following the principles outlined in the MITRE ATT&CK framework for web application security threats. The vulnerability also underscores the importance of maintaining up-to-date security patches and implementing comprehensive security awareness training for users to recognize potential social engineering attempts that might accompany such attacks.