CVE-2017-5084 in Chrome OS
Summary
by MITRE
Inappropriate implementation in image-burner in Google Chrome OS prior to 59.0.3071.92 allowed a local attacker to read local files via dbus-send commands to a BurnImage D-Bus endpoint.
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Analysis
by VulDB Data Team • 12/01/2019
The vulnerability identified as CVE-2017-5084 represents a critical access control flaw within the image-burner component of Google Chrome OS versions prior to 59.0.3071.92. This issue stems from an inappropriate implementation that fails to properly validate input parameters when processing D-Bus communication requests. The vulnerability specifically affects the BurnImage D-Bus endpoint which is designed to handle disk image burning operations but lacks adequate authorization checks. The flaw allows a local attacker with minimal privileges to exploit this endpoint and execute arbitrary dbus-send commands that can access and read local files on the system. This represents a classic privilege escalation vulnerability where a low-privilege user can gain unauthorized access to sensitive system resources through improper access controls. The vulnerability is categorized under CWE-284 which addresses inadequate access control mechanisms, specifically focusing on insufficient authorization checks in system components. From an operational perspective, this vulnerability poses significant risk to Chrome OS deployments as it enables local file disclosure without requiring elevated privileges. Attackers can leverage this flaw to read sensitive files including configuration data, user credentials, or system information that should remain protected. The impact extends beyond simple information disclosure as it can provide attackers with insights into system architecture and potentially enable further exploitation. The vulnerability aligns with ATT&CK technique T1005 which covers data from local system, and T1059 which encompasses command and scripting interpreter. The attack vector requires local system access and involves crafting malicious D-Bus commands that bypass normal access controls. The implementation flaw demonstrates a failure in applying the principle of least privilege where the BurnImage endpoint should only accept authorized commands from legitimate system processes. Security researchers identified that the vulnerability existed due to insufficient validation of D-Bus method calls and their associated parameters, allowing attackers to manipulate the interface to access unintended file system resources. The exploitation process involves sending crafted dbus-send commands that target the vulnerable BurnImage endpoint, effectively circumventing the intended security boundaries of the system. Organizations using affected Chrome OS versions face potential data breaches and unauthorized system access, making immediate patching essential for maintaining security posture. The vulnerability highlights the importance of proper D-Bus security implementation and input validation in system-level components. Mitigation strategies should focus on updating to Chrome OS version 59.0.3071.92 or later, implementing additional access controls for D-Bus endpoints, and conducting thorough security reviews of system components that handle inter-process communication. The flaw also emphasizes the need for comprehensive security testing of D-Bus interfaces and proper authorization mechanisms to prevent unauthorized access to system resources. Organizations should consider implementing additional monitoring for suspicious D-Bus activity and establish robust patch management processes to address such vulnerabilities promptly. The vulnerability demonstrates how seemingly isolated components can create significant security risks when proper access control measures are not implemented, reinforcing the importance of security-by-design principles in system architecture.