BYOVDFinder helps you check which drivers from loldrivers.io are not blocked by the current HVCI (Hypervisor Code Integrity) blocklist on your system. This is particularly useful for BYOVD (Bring Your Own Vulnerable Driver) attack paths where vulnerable drivers are permitted to load despite HVCI being enabled.
HVCI is a security feature in Windows that helps protect against attacks like kernel exploits by verifying the integrity of code running at the kernel level. It blocks drivers that are unsigned or known to be malicious by checking them against an internal blocklist. If a driver is not recognized, it will be blocked to prevent possible exploitation. However, according to Microsoft, the list is updated once or twice a year, giving us plenty of time to use drivers that haven't yet been blocked.
Option 1: Python Script
- Python 3.x
driversipolicy.p7bfile containing HVCI blocklist data (optional)
Option 2: PowerShell Script
- PowerShell 5.1+ (Windows)
The Python script requires a local XML file containing the HVCI blocklist.
Step 1: Extract driversipolicy.p7b to XML You can obtain the XML in one of two ways:
- To extract the
driversipolicy.p7bfile into XML format, you can use the script from Mattifestation's Gist.
IEX(New-Object net.WebClient).DownloadString("https://gist.githubusercontent.com/mattifestation/92e545bf1ee5b68eeb71d254cec2f78e/raw/a9b55d31075f91b467a8a37b9d8b2d84a0aa856b/CIPolicyParser.ps1")
ConvertTo-CIPolicy -BinaryFilePath 'C:\Windows\System32\CodeIntegrity\driversipolicy.p7b' -XmlFilePath (Join-Path $env:USERPROFILE 'Desktop\driversipolicy.xml')- Alternatively, you can get the Microsoft Vulnerable Driver Blocklist XML directly from Microsoft's Vulnerable Driver Blocklist page. Copy the XML contents and use it directly without the need to parse the .p7b file.
Step 2: Run the Python Script
- After extracting the
driversipolicy.p7bfile to XML format, run the Python script with the following command:
python3 finder.py driversipolicy.xmlThe PowerShell script gives you two ways to run it:
- No input required: It will attempt to fetch the blocklist from your machine or download the latest one from Microsoft.
.\finder.ps1- With input: Provide a custom XML file as input. You can generate this file using the method described in the Python script section above.
.\finder.ps1 -XmlFile "C:\Path\To\driversipolicy.xml"- Or just run it directly via one-liner.
IEX(New-Object net.WebClient).DownloadString("https://raw.githubusercontent.com/ghostbyt3/BYOVDFinder/refs/heads/main/finder.ps1")
$ python3 finder.py driversipolicy.xml
_____ _______ _____ ___ _ _
| _ ) \ / / _ \ \ / / \| __(_)_ _ __| |___ _ _
| _ \\ V / (_) \ V /| |) | _|| | ' \/ _` / -_) '_|
|___/ |_| \___/ \_/ |___/|_| |_|_||_\__,_\___|_|
DRIVER: <driver>.sys
Link: https://www.loldrivers.io/drivers/<id>
MD5: <hash>
SHA1: <hash>
SHA256: <hash>
--------------------------------------------------------------------------------
DRIVER: <driver>.sys
Link: https://www.loldrivers.io/drivers/<id>
MD5: <hash>
SHA1: <hash>
SHA256: <hash>
--------------------------------------------------------------------------------
[::]
[+] Number of Blocked Drivers: XXXX
[+] Number of Allowed Drivers: XX
- Retrieves the latest list of Bring Your Own Vulnerable Driver (BYOVD) entries from loldrivers.io API, including hashes, signatures, and metadata.
- Parses Microsoft's Hypervisor-Protected Code Integrity (HVCI) policy XML to detect which vulnerable drivers are actively blocked by hash or certificate rules, providing clear allow/block classification.
- Cross-checks driver hashes (MD5/SHA1/SHA256) and certificates from loldrivers.io against deny rules in HVCI policy XML to identify vulnerable drivers that are not blocked.