Cybercriminals continue to evolve their attack strategies, and the latest example is the exploitation of vulnerabilities in Paragon Partition Manager’s BioNTdrv.sys driver. Threat actors are leveraging this flaw in a Bring Your Own Vulnerable Driver (BYOVD) attack to escalate privileges and deploy ransomware on Windows systems.
This tactic is particularly dangerous because it bypasses security protections, disables endpoint defenses, and allows attackers to execute malicious code at the highest privilege level. As ransomware groups increasingly adopt this technique, understanding how BYOVD works and how to mitigate the risks is critical.
How the BYOVD Attack Works
BYOVD attacks involve hackers introducing a signed yet vulnerable driver into a system and then exploiting its weaknesses. Even though the driver itself is legitimate, its security flaws allow attackers to execute malicious operations, such as disabling security software and running arbitrary code with SYSTEM privileges.
In the case of the Paragon Partition Manager exploit, researchers at Microsoft identified five critical vulnerabilities in the BioNTdrv.sys driver:
CVE-2025-0288 – Arbitrary kernel memory write due to improper input sanitization.
CVE-2025-0287 – Null pointer dereference flaw leading to kernel execution.
CVE-2025-0286 – Memory write vulnerability allowing privilege escalation.
CVE-2025-0285 – Kernel memory mapping flaw that leads to SYSTEM-level compromise.
CVE-2025-0289 – Insecure kernel resource access, enabling malware execution at the highest privileges.
Real-World Impact of BYOVD Ransomware Attacks
1. Disabling Antivirus and EDR Solutions
Once attackers gain control over a vulnerable driver, they can disable security solutions like Windows Defender, CrowdStrike, or SentinelOne. This leaves the system unprotected, allowing ransomware deployment without detection.
2. Deploying Ransomware Payloads
After disabling security defenses, attackers execute ransomware, encrypting files and demanding payments from victims. The BlackByte and AvosLocker ransomware gangs have previously used BYOVD attacks to cripple security measures before launching their payloads.
3. Targeting Enterprise Systems
BYOVD techniques are highly effective in large-scale ransomware campaigns targeting hospitals, financial institutions, and government agencies. These attacks often result in operational shutdowns, data exfiltration, and massive financial losses.
Defensive Measures Against BYOVD Attacks
To mitigate the risks posed by BYOVD attacks, organizations and individuals must implement proactive security measures:
✅ 1. Enable Windows Driver Blocklisting
Windows provides a Vulnerable Driver Blocklist feature that prevents execution of known exploitable drivers like BioNTdrv.sys.
✅ 2. Implement Kernel Mode Driver Enforcement
Security features such as Hypervisor-Protected Code Integrity (HVCI) ensure that only trusted drivers run in the system.
✅ 3. Regularly Update Software & Drivers
Ensure that all drivers, particularly those from third-party software, are up to date with security patches.
✅ 4. Monitor System Logs & Anomalous Behavior
Use SIEM (Security Information and Event Management) solutions to detect unusual driver loading activity, privilege escalations, or security software shutdown attempts.
✅ 5. Implement Zero Trust Architecture
Restrict driver installation permissions to only trusted administrators and use Endpoint Detection and Response (EDR) solutions to monitor for malicious activities.
Conclusion
BYOVD attacks, particularly those exploiting Paragon Partition Manager’s BioNTdrv.sys driver, represent a growing cybersecurity challenge. As ransomware gangs increasingly weaponize vulnerable drivers, organizations must adopt a proactive security strategy to mitigate these threats.
By enabling driver blocklisting, enforcing kernel protection, and strengthening endpoint defenses, security teams can reduce the risk of BYOVD exploitation and better protect their systems from ransomware attacks.
As always, staying ahead in cybersecurity means continuously updating defenses and remaining vigilant against emerging threats.