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Introduction:
The Bring Your Own Vulnerable Driver (BYOVD) attack technique continues to be a favored method for adversaries seeking to disable security controls and gain kernel-level privileges. By leveraging legitimate but vulnerable signed drivers, attackers can bypass user-mode protections and execute arbitrary code with SYSTEM privileges. The recent addition of TVicPort64.sys to the LOLDrivers project, assigned CVE-2026-30769, highlights a critical vulnerability in a driver signed as far back as 2006, enabling arbitrary physical memory mapping and local privilege escalation (LPE).
Learning Objectives:
- Understand the BYOVD attack vector and how vulnerable drivers like TVicPort64.sys are exploited.
- Learn to identify and mitigate the CVE-2026-30769 vulnerability using security tools and system hardening.
- Gain hands-on knowledge of driver blocklisting, memory protection, and detection strategies across Windows environments.
You Should Know:
1. Dissecting TVicPort64.sys and the BYOVD Exploit Chain
The TVicPort64.sys driver, developed by EnTech Taiwan and signed in 2006, is designed to provide low-level hardware access. However, its implementation contains two critical flaws that allow a user-mode application to map arbitrary physical memory into user space. This capability enables an attacker to read from and write to any physical memory location, effectively achieving kernel code execution and local privilege escalation (LPE) to SYSTEM. The driver’s ancient signature date means it may still be present on legacy systems or mistakenly trusted by modern security products that rely solely on signature verification.
The exploit chain typically involves the following steps:
- Driver Deployment: The attacker places the vulnerable driver (
TVicPort64.sys) on the target system. - Service Installation: Using Windows Service Control Manager (
sc.exe) or custom code, the driver is installed and started as a service. - Memory Mapping: The attacker’s user-mode application communicates with the driver via `DeviceIoControl` to map arbitrary physical memory.
- Privilege Escalation: By overwriting critical kernel structures (e.g., `_EPROCESS` token), the attacker elevates their process to SYSTEM privileges or disables security software.
Step‑by‑Step Guide: Identifying and Blocking TVicPort64.sys
To defend against this driver, administrators must proactively block it using Windows security features.
Step 1: Verify Driver Presence
Use PowerShell to check if the driver is present on the system:
Get-WmiObject Win32_SystemDriver | Where-Object {$_.Name -like "TVicPort"} | Select-Object Name, State, PathName
Or use the Command
sc query | findstr /i "TVicPort"
Step 2: Locate the Driver File
Search common driver directories:
dir C:\Windows\System32\drivers\TVicPort64.sys /s /p
Step 3: Add to Driver Blocklist (Windows Defender Application Control)
If WDAC is enabled, add the driver’s hash or publisher to a blocklist policy:
Generate a block rule for the specific driver hash New-CIPolicy -FilePath .\BlockPolicy.xml -DriverFilePath "C:\Windows\System32\drivers\TVicPort64.sys" -UserPEs -Level FilePublisher Merge with existing policy Merge-CIPolicy -OutputFilePath .\MergedPolicy.xml -PolicyPaths .\ExistingPolicy.xml, .\BlockPolicy.xml Convert and deploy ConvertFrom-CIPolicy -XmlFilePath .\MergedPolicy.xml -BinaryFilePath .\MergedPolicy.bin Copy-Item .\MergedPolicy.bin C:\Windows\System32\CodeIntegrity\SIPolicy.p7b
Step 4: Use PnPUtil to Block via Device ID
Block the driver package using PnPUtil (requires admin rights):
pnputil /block-driver TVicPort64.inf
- Detecting Exploitation Attempts and Leveraging LOLDrivers for Defense
The LOLDrivers project (Living Off the Land Drivers) serves as a curated list of known vulnerable drivers that attackers use in BYOVD attacks. Security teams should integrate this list into their SIEM and EDR tools for real-time detection. For CVE-2026-30769, detection focuses on anomalous service creation, driver load events, and memory access patterns.
Step‑by‑Step Guide: Detection and Monitoring
Step 1: Monitor Service Installations
Configure Event Viewer to log service installations (Event ID 7045) and driver load events (Event ID 7036). Use PowerShell to query for recent suspicious driver loads:
Get-WinEvent -FilterHashtable @{LogName='System'; ID=7045} | Where-Object { $_.Message -like "TVicPort" }
Step 2: Leverage Sysmon for Advanced Detection
Sysmon event ID 6 (Driver Loaded) can be used to log all driver loads. Ensure Sysmon is configured with a rule to alert on known vulnerable drivers:
<Sysmon schemaversion="4.81"> <EventFiltering> <DriverLoad onmatch="exclude"> <!-- Exclude known safe drivers --> </DriverLoad> <DriverLoad onmatch="include"> <Signature condition="contains">EnTech</Signature> <Image condition="contains">TVicPort</Image> </DriverLoad> </EventFiltering> </Sysmon>
Step 3: Correlate with LOLDrivers Repository
Automate the detection by pulling the latest LOLDrivers list and comparing against loaded drivers:
$loldrivers = Invoke-RestMethod -Uri "https://raw.githubusercontent.com/magicsword-io/LOLDrivers/main/drivers.json"
$loadedDrivers = Get-WmiObject Win32_SystemDriver | Select-Object Name, PathName
foreach ($driver in $loadedDrivers) {
if ($loldrivers.drivers.name -contains $driver.Name) {
Write-Warning "Vulnerable driver detected: $($driver.Name)"
}
}
Step 4: Implement Memory Protection (Kernel Patch Protection)
While KPP (PatchGuard) prevents patching the kernel on 64-bit systems, it does not prevent drivers from mapping physical memory. Use Microsoft’s HVCI (Hypervisor-protected Code Integrity) to enforce that drivers are signed and adhere to security policies, mitigating the risk of loading TVicPort64.sys:
Check HVCI status Get-ComputerInfo -Property "DeviceGuard" Enable via Registry reg add "HKLM\SYSTEM\CurrentControlSet\Control\DeviceGuard" /v EnableVirtualizationBasedSecurity /t REG_DWORD /d 1 /f reg add "HKLM\SYSTEM\CurrentControlSet\Control\DeviceGuard" /v RequirePlatformSecurityFeatures /t REG_DWORD /d 1 /f
3. Exploitation Deep-Dive (Educational Context)
Understanding how the vulnerability works is crucial for defense. The vulnerability lies in the IOCTL handler that allows arbitrary physical memory mapping. An attacker can use the following pseudo-code to interact with the driver:
include <windows.h>
define IOCTL_MAP_PHYSICAL_MEMORY CTL_CODE(FILE_DEVICE_UNKNOWN, 0x800, METHOD_NEITHER, FILE_ANY_ACCESS)
typedef struct _MAP_PHYSICAL_MEMORY {
ULONG_PTR PhysicalAddress;
ULONG_PTR Size;
PVOID MappedAddress;
} MAP_PHYSICAL_MEMORY;
HANDLE hDevice = CreateFile(L"\\.\TVicPort", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
if (hDevice != INVALID_HANDLE_VALUE) {
MAP_PHYSICAL_MEMORY map;
map.PhysicalAddress = 0x1000; // Target physical page
map.Size = 0x1000;
DWORD bytesReturned;
DeviceIoControl(hDevice, IOCTL_MAP_PHYSICAL_MEMORY, &map, sizeof(map), &map, sizeof(map), &bytesReturned, NULL);
// Write to kernel memory via map.MappedAddress
}
Defenders should use tools like Driver Verifier to test for such vulnerabilities in-house and ensure that IOCTL handlers are properly validating inputs.
4. Strengthening the Environment: Proactive Mitigations
Beyond blocking the specific driver, organizations should adopt a Zero Trust approach to driver loading.
Step‑by‑Step Guide: Enforce Code Integrity Policies
- Enable Memory Integrity (Core Isolation) in Windows Security to prevent unsigned or vulnerable drivers from loading.
- Use Attack Surface Reduction (ASR) rules to block processes from creating or running suspicious drivers:
Add-MpPreference -AttackSurfaceReductionRules_Ids "d3e037e4-6a0e-4b5c-8a1f-2e3f4b5c6d7e" -AttackSurfaceReductionRules_Actions Enabled
- Deploy LSA Protection to prevent credential dumping via kernel exploits.
- Regularly audit third-party drivers using tools like `driverquery` and compare against the LOLDrivers list.
driverquery /v /fo csv > drivers.csv
5. Linux Parallels: Kernel Module Security
While CVE-2026-30769 is Windows-specific, the concept of exploiting kernel modules is universal. On Linux, defenders can use:
– Lockdown LSM to restrict kernel module loading.
– Module Signing to enforce that only signed modules can be loaded.
– `lsmod` and `modprobe` to audit loaded modules.
List loaded modules lsmod Check module signature modinfo tvicport.ko | grep signer Blacklist a vulnerable module echo "blacklist tvicport" >> /etc/modprobe.d/blacklist.conf
What Undercode Say:
- Key Takeaway 1: The addition of TVicPort64.sys (CVE-2026-30769) to LOLDrivers is a critical signal for defenders to immediately audit and block this driver across all systems, especially those running legacy hardware.
- Key Takeaway 2: BYOVD attacks remain highly effective due to the trust placed in signed drivers. Proactive defenses like WDAC, HVCI, and LOLDrivers integration are essential to close this gap before attackers can exploit them.
The discovery of CVE-2026-30769 in a driver signed nearly two decades ago underscores a persistent supply chain vulnerability: outdated, yet still digitally signed, binaries that slip through security perimeters. Defenders must shift from reactive signature-based detection to proactive integrity control. The LOLDrivers project is an invaluable resource, but it must be paired with automated deployment of driver blocklists. As threat actors increasingly leverage these drivers for ransomware deployment and EDR evasion, organizations that fail to implement kernel-level protections risk catastrophic breaches. Continuous monitoring, coupled with enforced code integrity, is no longer optional—it is the baseline for modern security hygiene.
Prediction:
The exploitation of TVicPort64.sys will likely appear in ransomware campaigns within the next six months, as its inclusion in LOLDrivers signals its weaponization potential. This trend will accelerate the adoption of Microsoft’s HVCI and WDAC among enterprise environments, while also pushing driver developers to adopt secure coding practices and hardware-enforced stack protection. Additionally, we can expect an increase in third-party tools that automatically pull from the LOLDrivers repository to enforce real-time blocklisting across fleets.
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IT/Security Reporter URL:
Reported By: New Loldrivers – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
