Microsoft warns of a Paragon Partition Manager BioNTdrv.sys driver zero-day flaw actively exploited by ransomware gangs in attacks.
Microsoft discovered five vulnerabilities in the Paragon Partition Manager BioNTdrv.sys driver. The IT giant reported that one of these flaws is exploited by ransomware groups in zero-day attacks.
Paragon Partition Manager, available in Community and Commercial versions, manages hard drive partitions using the BioNTdrv.sys driver. This kernel-level driver enables low-level access with elevated privileges for data management.
The researchers discovered five vulnerabilities in Paragon Partition Manager’s BioNTdrv.sys driver, versions before 2.0.0. The flaws include arbitrary kernel memory mapping and write vulnerabilities, a null pointer dereference, insecure kernel resource access, and an arbitrary memory move vulnerability.
Microsoft reported that ransomware groups exploited CVE-2025-0289 to gain SYSTEM-level access. Both Paragon Software and Microsoft have patched the flaw and blocked vulnerable BioNTdrv.sys versions.
“Microsoft researchers have identified four vulnerabilities in Paragon Partition Manager version 7.9.1 and a fifth specific vulnerability (CVE-2025-0289) affecting version 17. These vulnerabilities, particularly in BioNTdrv.sys versions 1.3.0 and 1.5.1, allow attackers to achieve SYSTEM-level privilege escalation, which surpasses typical administrator permissions. The vulnerabilities also enable attackers to manipulate the driver via device-specific Input/Output Control (IOCTL) calls, potentially resulting in privilege escalation or system crashes (e.g., a Blue Screen of Death, or BSOD).” reads the advisory published by CERT/CC. “Even if Paragon Partition Manager is not installed, attackers can install and misuse the vulnerable driver through the BYOVD method to compromise the target machine.”
Below are the vulnerabilities discovered by Microsoft:
Identified Vulnerabilities:
- CVE-2025-0288 An arbitrary kernel memory vulnerability in version 7.9.1 caused by the memmove function, which fails to sanitize user-controlled input. This allows an attacker to write arbitrary kernel memory and achieve privilege escalation.
- CVE-2025-0287 A null pointer dereference vulnerability in version 7.9.1 caused by the absence of a valid MasterLrp structure in the input buffer. This allows an attacker to execute arbitrary kernel code, enabling privilege escalation.
- CVE-2025-0286 An arbitrary kernel memory write vulnerability in version 7.9.1 due to improper validation of user-supplied data lengths. This flaw can allow attackers to execute arbitrary code on the victim’s machine.
- CVE-2025-0285 An arbitrary kernel memory mapping vulnerability in version 7.9.1 caused by a failure to validate user-supplied data lengths. Attackers can exploit this flaw to escalate privileges.
- CVE-2025-0289 An insecure kernel resource access vulnerability in version 17 caused by failure to validate the MappedSystemVa pointer before passing it to HalReturnToFirmware. This allows attackers to compromise the affected service.
Paragon Software released BioNTdrv.sys v2.0.0 to address the vulnerabilities above. Users should update Paragon Partition Manager and ensure Windows’ Vulnerable Driver Blocklist is enabled. On Windows 11, it is active by default. Enterprises should apply the blocklist to prevent threat actors from exploiting older driver versions (1.3.0 & 1.5.1).
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