Bypass Record
BYOVD (Vulnerable Driver) × Microsoft Defender
A publicly-reported instance of BYOVD (Vulnerable Driver) bypassing Microsoft Defender, recorded with its original source. Factual record; no assessment of any specific deployment.
Mechanism
Attackers load the vulnerable signed Huawei driver HWAuidoOs2Ec.sys via BYOVD. By sending a target process ID through a privileged IOCTL handler, the driver calls ZwTerminateProcess from kernel mode, bypassing user-mode EDR protections including Protected Process Light (PPL). It polls for targeted security processes every 100ms and terminates them.
Detection & mitigation
Monitor for the loading of known vulnerable drivers (e.g., HWAuidoOs2Ec.sys) via Sysmon Event ID 6 (driver loaded) or EDR telemetry, and alert on their presence especially when not part of standard system images. Mitigate by blocking the vulnerable driver's hash or certificate via Windows Defender Application Control (WDAC) or vulnerable driver blocklist, and ensure endpoint protection solutions are configured to prevent loading of untrusted drivers.
This is a record of a publicly-reported event, not an assessment of any specific organization's deployment. Detection and mitigation notes are drawn from the cited source. Where the source is silent, fields are omitted.