Threat Intelligence Analysis: PhantomKiller (BYOVD)
PhantomKiller is a new EDR/AV evasion proof-of-concept that weaponizes a legitimate, fully signed Lenovo kernel driver (BootRepair.sys). It employs a classic Bring Your Own Vulnerable Driver (BYOVD) technique with an exceptionally simple and reliable implementation: it enables any low-privileged user (or after driver loading) to terminate any process on the system, including Protected Process Light (PPL) processes protected by modern EDRs.
Technical Details of the Driver & Vulnerability
•Driver: BootRepair.sys (part of Lenovo PC Manager)
•SHA256: 5ab36c116767eaae53a466fbc2dae7cfd608ed77721f65e83312037fbd57c946
•Signature: Valid Lenovo signature (trusted by Windows; currently 0 detections on VirusTotal)
•Build date: ~2018 (legacy driver still not broadly blocked)
Reverse Engineering Highlights (IDA Pro):
•Creates device object \\Device\\::BootRepair without a secure DACL.
•Exposes symbolic link \\DosDevices\\BootRepair — any user-mode process can open it via CreateFileW("\\\\.\\BootRepair").
•Only one IOCTL is exposed: 0x222014.
•The handler simply validates a 4-byte buffer (DWORD PID) and calls ZwTerminateProcess directly in kernel context with zero checks on caller, PID, or protections.
Result: Ring-0 termination bypasses all EDR objection handling, PPL, minifilter callbacks, and process protections.
Simple PoC
HANDLE h = CreateFileW(L"\\\\.\\BootRepair", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
DeviceIoControl(h, 0x222014, &pid, sizeof(pid), NULL, 0, &ret, NULL);
•If the driver is already loaded → direct low-priv exploitation.
•Otherwise → classic BYOVD load via sc.exe.
Successfully tested against CrowdStrike Falcon and claimed to work universally due to the kernel-trusted nature of the driver.
Cross-Checked Intelligence
•Disclosed May 19-21, 2026 by Jehad Abu Dagga (@jehadbudagga).
•Official repo:
github.com/redteamfortress/P…
•Rapidly added to LOLDrivers by the community.
•Part of the ongoing 2026 wave of BYOVD EDR killers (ESET tracked 54 tools abusing 35 vulnerable drivers this year).
Key IOCs:
•File: BootRepair.sys (SHA256 above)
•Device: \\.\BootRepair / \\Device\\::BootRepair
•IOCTL: 0x222014
•Service name: PhantomKiller (or attacker-chosen)
References:
• Full technical write-up:
medium.com/@jehadbudagga/pha…
• PoC Repository:
github.com/redteamfortress/P…
.
#CyberSecurity #ThreatIntelligence #EDR #BYOVD #RedTeaming #InfoSec #WindowsSecurity #Vulnerability #CyberThreats #MalwareAnalysis