CVE-2018-0526 in Office
Summary
by MITRE
Cybozu Office 10.0.0 to 10.7.0 allow remote attackers to display an image located in an external server via unspecified vectors.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 02/21/2020
The vulnerability identified as CVE-2018-0526 affects Cybozu Office versions 10.0.0 through 10.7.0, representing a significant security flaw that enables remote attackers to execute unauthorized image loading from external servers. This issue falls under the category of insecure direct object references and improper access control mechanisms, as it allows adversaries to bypass normal access restrictions and retrieve content from unintended locations. The vulnerability stems from insufficient validation of image sources within the application's handling of external resources, creating an attack vector that could be exploited without requiring authentication or prior access to the system.
The technical implementation of this flaw involves the application's failure to properly sanitize or validate external image references, permitting attackers to craft malicious requests that load images from arbitrary external servers. This behavior creates a potential pathway for information disclosure, as attackers could potentially access internal resources that should remain protected. The unspecified vectors mentioned in the description suggest that multiple attack paths may exist, including but not limited to web-based interfaces, document processing functions, or network communication protocols. This vulnerability operates at the application layer and could be exploited through various means including crafted web requests, malicious documents, or manipulated network traffic that triggers the insecure image loading mechanism.
The operational impact of this vulnerability extends beyond simple image loading, as it could potentially enable more sophisticated attacks including cross-site scripting scenarios, data exfiltration, or even privilege escalation depending on the application's architecture and access controls. Attackers could leverage this weakness to harvest sensitive information from internal networks, monitor user activities through image-based tracking mechanisms, or create persistent access points through carefully crafted malicious content. The vulnerability affects organizations using Cybozu Office in enterprise environments where internal resources might be accessible through external image loading mechanisms, potentially exposing confidential data or system information to unauthorized parties. This issue represents a critical concern for organizations that rely on document processing and collaboration platforms, as it undermines the fundamental security assumptions of content isolation and access control.
Mitigation strategies for CVE-2018-0526 should prioritize immediate patching of affected systems to the latest available versions that contain fixes for the image loading vulnerability. Organizations should implement strict network policies that restrict external resource access and establish comprehensive content filtering mechanisms to prevent loading of images from untrusted sources. The implementation of web application firewalls and security monitoring systems can help detect and prevent exploitation attempts. Additionally, security teams should conduct thorough assessments of their Cybozu Office deployments to identify any custom configurations or third-party integrations that might exacerbate the vulnerability. This remediation approach aligns with cybersecurity frameworks such as the mitre ATT&CK framework, specifically addressing techniques related to command and control communications and credential access through web-based attacks. Organizations should also consider implementing principle of least privilege controls and regular security assessments to prevent similar vulnerabilities from emerging in other components of their document management systems. The vulnerability demonstrates the importance of validating all external resource references and implementing robust access controls as outlined in industry standards such as CWE-20, which addresses improper handling of resources and access control mechanisms.