CVE-2016-1153 in Office
Summary
by MITRE
customapp in Cybozu Office 9.9.0 through 10.3.0 allows remote authenticated users to cause a denial of service via unspecified vectors, a different vulnerability than CVE-2015-8489.
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Analysis
by VulDB Data Team • 07/30/2018
The vulnerability identified as CVE-2016-1153 affects Cybozu Office versions 9.9.0 through 10.3.0, specifically within the customapp component. This issue represents a denial of service vulnerability that can be exploited by remote authenticated users, distinguishing it from the previously identified CVE-2015-8489 which addressed different attack vectors. The vulnerability resides in the customapp functionality that processes user-supplied data, creating potential pathways for malicious actors to disrupt service availability. Organizations utilizing these Cybozu Office versions face significant operational risks as this flaw can be leveraged to systematically deny legitimate users access to critical business applications and services.
The technical nature of this vulnerability stems from insufficient input validation and error handling mechanisms within the customapp module. When authenticated users submit crafted requests or data through the customapp interface, the system fails to properly sanitize or validate the incoming information, potentially leading to resource exhaustion or application crashes. This weakness creates an attack surface where malicious actors can exploit the system's inability to handle malformed inputs gracefully, resulting in service disruption. The vulnerability's classification aligns with CWE-20, which addresses "Improper Input Validation" as a fundamental weakness in software design that commonly leads to denial of service conditions and other security incidents. The specific implementation details suggest that the flaw exists in how the application processes user-defined parameters or configuration data within the customapp framework, creating opportunities for resource exhaustion attacks that can effectively shut down system functionality.
From an operational impact perspective, this vulnerability presents a substantial risk to business continuity and productivity within organizations relying on Cybozu Office platforms. The denial of service condition can render critical collaboration tools and document management systems inaccessible to legitimate users, potentially affecting multiple departments and workflow processes simultaneously. Attackers can exploit this vulnerability to systematically disrupt business operations, requiring significant time and resources for recovery efforts. The remote nature of the attack means that threat actors do not require physical access to the system, making the vulnerability particularly dangerous in networked environments where multiple users interact with the platform. Organizations may experience downtime ranging from partial service degradation to complete system unavailability, depending on the scale and sophistication of the attack.
Mitigation strategies for CVE-2016-1153 should prioritize immediate patching of affected Cybozu Office versions to address the underlying validation and error handling issues. System administrators should implement network segmentation to limit access to the customapp functionality and reduce the potential attack surface. Enhanced monitoring and logging of user activities within the customapp module can help detect anomalous behavior patterns that may indicate exploitation attempts. Security teams should also consider implementing rate limiting and input validation controls to prevent resource exhaustion attacks, while maintaining regular vulnerability assessments to identify similar weaknesses in other components. The remediation process should follow established security protocols including thorough testing of patches in controlled environments before deployment to production systems, ensuring that the fixes do not introduce new compatibility issues or service disruptions. Organizations should also review their incident response procedures to ensure rapid detection and mitigation of similar vulnerabilities in the future, aligning with industry best practices for maintaining secure software environments.