CVE-2018-16169 in Remote Service
Summary
by MITRE
Cybozu Remote Service 3.0.0 to 3.1.0 allows remote authenticated attackers to upload and execute Java code file on the server via unspecified vectors.
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Analysis
by VulDB Data Team • 04/27/2020
The vulnerability identified as CVE-2018-16169 affects Cybozu Remote Service versions 3.0.0 through 3.1.0, representing a critical security flaw that enables remote authenticated attackers to execute arbitrary Java code on affected servers. This vulnerability stems from insufficient input validation and file upload controls within the application's remote service functionality, creating a pathway for malicious actors to bypass security restrictions and deploy malicious payloads. The flaw exists in the server-side processing of file uploads, where proper sanitization and validation mechanisms fail to prevent the execution of potentially harmful code. Attackers with legitimate authentication credentials can exploit this vulnerability to upload Java files that contain malicious code, subsequently executing these payloads on the target server with the privileges of the service account.
The technical nature of this vulnerability aligns with CWE-434, which describes insecure file upload vulnerabilities where applications accept files without proper validation, allowing attackers to upload executable content. This weakness creates a direct code execution vector that can be leveraged for privilege escalation, data exfiltration, and system compromise. The vulnerability's impact is amplified by the fact that it requires only authenticated access, meaning that attackers who have legitimate user credentials can exploit the flaw without requiring additional unauthorized access. The unspecified vectors mentioned in the description suggest that the vulnerability may exist across multiple upload endpoints or methods within the service, making it particularly dangerous as it could be exploited through various attack surfaces. This characteristic also indicates a design flaw in the application's security architecture where file handling mechanisms are not consistently protected across all service components.
From an operational perspective, this vulnerability poses significant risks to organizations relying on Cybozu Remote Service for their business operations. The ability to execute arbitrary Java code remotely can lead to complete system compromise, allowing attackers to establish persistent backdoors, steal sensitive data, or disrupt business operations. The vulnerability's severity is compounded by the fact that it affects a remote service that likely handles sensitive corporate data and may be accessible to multiple users within an organization. Organizations may experience unauthorized access to confidential information, system downtime, and potential regulatory compliance violations. The attack surface extends beyond simple code execution to include potential lateral movement within networks, as compromised servers could serve as launching points for further attacks against other systems. The vulnerability also represents a significant risk to business continuity and data integrity, as it can enable attackers to manipulate or destroy critical business data.
Mitigation strategies for CVE-2018-16169 should focus on immediate patching of affected versions to address the core file upload validation issues. Organizations must implement comprehensive input validation and file type checking mechanisms to prevent unauthorized code execution, ensuring that all uploaded files undergo strict sanitization before processing. Network segmentation and access controls should be reinforced to limit the potential impact of successful exploitation, while monitoring systems should be enhanced to detect suspicious upload activities and code execution attempts. Security configurations should include disabling unnecessary file upload capabilities and implementing strict file extension validation combined with content inspection to prevent malicious code from being executed. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other applications and systems. The remediation process should also include user access reviews to ensure that only authorized personnel have access to upload functionality, and that proper authentication mechanisms are in place to prevent credential compromise. Additionally, organizations should implement application-level firewalls and intrusion detection systems to monitor for exploitation attempts and provide additional layers of protection against this type of vulnerability.