CVE-2025-8067 in Red Hat
Summary
by MITRE • 08/28/2025
A flaw was found in the Udisks daemon, where it allows unprivileged users to create loop devices using the D-BUS system. This is achieved via the loop device handler, which handles requests sent through the D-BUS interface. As two of the parameters of this handle, it receives the file descriptor list and index specifying the file where the loop device should be backed. The function itself validates the index value to ensure it isn't bigger than the maximum value allowed. However, it fails to validate the lower bound, allowing the index parameter to be a negative value. Under these circumstances, an attacker can cause the UDisks daemon to crash or perform a local privilege escalation by gaining access to files owned by privileged users.
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Analysis
by VulDB Data Team • 10/09/2025
The vulnerability identified as CVE-2025-8067 resides within the UDisks daemon, a critical system component responsible for managing storage devices and file systems in Linux environments. This daemon operates through the D-BUS messaging system, enabling communication between various system services and user applications. The flaw manifests in the loop device handler functionality, which processes requests to create loop devices that allow files to be mounted as block devices. The security implications are particularly severe because UDisks daemon typically runs with elevated privileges, making it a prime target for privilege escalation attacks. The vulnerability specifically affects the validation logic within the D-BUS interface handler that processes loop device creation requests, creating a pathway for unauthorized access to system resources.
The technical implementation of this vulnerability stems from inadequate parameter validation within the loop device handler function. While the implementation correctly validates the upper bound of the index parameter to prevent buffer overflows or memory corruption, it completely omits validation of the lower bound. This oversight allows attackers to submit negative index values that bypass the intended safety checks. The function receives two critical parameters through the D-BUS interface: a file descriptor list and an index value that specifies which file in the list should serve as the backing store for the loop device. When a negative index is provided, the system's memory access patterns become unpredictable, potentially causing memory corruption or allowing access to memory locations that should remain protected. This flaw aligns with CWE-129, which addresses improper validation of array indices, and represents a classic example of insufficient input validation that can lead to arbitrary code execution or system instability.
The operational impact of this vulnerability extends beyond simple daemon crashes to encompass serious privilege escalation capabilities that could compromise entire system security. An unprivileged user can exploit this weakness to gain access to files that are normally restricted to privileged users, effectively breaking down the security boundaries that separate user processes from system-critical resources. The attack vector is particularly concerning because it leverages the legitimate D-BUS interface that UDisks daemon exposes, making the exploitation appear as normal system activity rather than malicious behavior. This characteristic allows the vulnerability to evade detection by traditional security monitoring systems that might not flag D-BUS communications as suspicious. The potential for local privilege escalation means that an attacker could potentially gain root access to the system, enabling them to modify critical system files, install backdoors, or exfiltrate sensitive data.
Mitigation strategies for CVE-2025-8067 must address both immediate patching requirements and long-term architectural improvements to prevent similar vulnerabilities. System administrators should prioritize applying the vendor-provided patches that implement proper lower bound validation for all index parameters within the loop device handler. Additionally, implementing runtime protections such as address space layout randomization and stack canaries can help mitigate potential exploitation attempts. Security hardening measures including restricting D-BUS access permissions for the UDisks daemon and implementing mandatory access controls through SELinux or AppArmor can limit the damage potential of successful exploitation. From a defensive perspective, organizations should monitor D-BUS traffic for unusual patterns related to loop device creation and implement behavioral analysis tools that can detect anomalous access to privileged file systems. This vulnerability demonstrates the critical importance of comprehensive input validation across all system interfaces and aligns with ATT&CK technique T1068, which covers local privilege escalation through system binary manipulation, emphasizing the need for robust security controls at multiple layers of the system architecture.