CVE-2025-14963 is a vulnerability categorized under CWE-20 (Improper Input Validation) found in the fekern.sys driver component of the Trellix Endpoint HX Agent (xAgent). This driver is installed with all existing versions of the HX Agent, specifically versions 30.x through 36.30.0-17. The vulnerability allows a threat actor who already has local user access with elevated privileges to leverage a Bring Your Own Vulnerable Driver (BYOVD) attack to gain access to the memory space of the critical Windows process lsass.exe, which handles security authority and credential management. The exploitation involves improper input validation within the fekern.sys driver, enabling unauthorized memory access. However, the Trellix HX Agent includes tamper protection mechanisms that restrict communication with the vulnerable driver to only the agent’s own processes, thereby preventing direct exploitation by unauthorized processes. The CVSS 4.0 base score is 6.2, indicating medium severity, with attack vector local, attack complexity high, privileges required high, and no user interaction needed. The vulnerability does not currently have known exploits in the wild, and no patches have been publicly linked yet. The vulnerability’s impact is significant because access to lsass.exe memory can lead to credential theft and privilege escalation, but exploitation requires existing elevated privileges and local access, limiting the attack surface. This vulnerability highlights the risk of BYOVD attacks where malicious drivers are loaded to bypass security controls and access sensitive system components.

The primary impact of CVE-2025-14963 is the potential for local attackers with elevated privileges to escalate their access by reading or manipulating the memory of lsass.exe, a critical Windows process responsible for managing security tokens and credentials. Successful exploitation could lead to credential theft, enabling lateral movement, persistence, and further privilege escalation within an organization’s network. Although the vulnerability requires high privileges and local access, it poses a significant risk in environments where endpoint agents are deployed broadly, such as enterprise networks. Attackers who gain initial footholds through phishing, malware, or insider threats could leverage this vulnerability to deepen their control and evade detection. The tamper protection in Trellix HX Agent reduces the likelihood of exploitation by restricting driver communication, but if bypassed, the impact could be severe. Organizations relying on Trellix Endpoint HX Agent should consider this vulnerability a risk to confidentiality and integrity of credentials and system security. The absence of known exploits in the wild currently reduces immediate risk, but the potential for future exploitation remains, especially if attackers develop methods to bypass tamper protections.

Organizations should prioritize the following mitigation steps: 1) Monitor Trellix vendor advisories closely for patches or updates addressing CVE-2025-14963 and apply them promptly once available. 2) Enforce strict local privilege management policies to minimize the number of users with elevated privileges, reducing the pool of potential attackers who can exploit this vulnerability. 3) Implement endpoint detection and response (EDR) solutions capable of detecting anomalous driver loading or attempts to access lsass.exe memory. 4) Harden tamper protection configurations and verify their integrity regularly to prevent bypass attempts. 5) Conduct regular audits of installed drivers and block unauthorized or unsigned drivers from loading on endpoints. 6) Employ application whitelisting and code integrity policies to restrict execution of untrusted code and drivers. 7) Educate users and administrators about the risks of local privilege escalation and the importance of maintaining least privilege principles. 8) Consider network segmentation and isolation of critical systems to limit lateral movement if exploitation occurs. These targeted controls go beyond generic advice by focusing on the specific attack vector (BYOVD) and the protection mechanisms inherent to the Trellix HX Agent environment.