Analysis of NullkD.sys: suspicious verdict, risk score 58/100. 1 YARA match. SHA256 b966539685ff4373. Kernel imports, IOCTL codes, MITRE ATT&CK, and code-signing details.
DriverShield analyzed the Windows kernel driver NullkD.sys and assigned a verdict of Suspicious with a composite risk score of 58/100, indicating some risk signals warranting review (30-59 band).
| Verdict | Suspicious (58/100) |
| YARA matches | 1 |
| File size | 53760 bytes |
| Analyzed | 2026-04-02 |
| SHA256 | b966539685ff4373079abc693bc0a298aeb8c57301a8a330c1fb860453787338 |
| SHA1 | 53c688fdd2f4580d972d42dbdec2e1c5d7c028a1 |
| MD5 | c3283cc8f50287cab25bdf3f8cbd30da |
Each component is scored 0-100 and then weighted into the composite. See the analysis methodology for the exact formula.
| Component | Sub-score |
|---|---|
| Multi-engine consensus | 0 / 100 |
| YARA signature matches | 30 / 100 |
| Dangerous kernel imports | 100 / 100 |
| IOCTL dispatch surface | 48 / 100 |
| Known-vulnerable corpus | 0 / 100 |
| Code-signing state | 50 / 100 |
| Packing and entropy | 0 / 100 |
| Dynamic behaviour | 0 / 100 |
| CVE cross-reference | 0 / 100 |
Kernel-mode APIs resolved from the Import Address Table of NullkD.sys, ranked by exploitation relevance.
| API | Risk | Why it matters |
|---|---|---|
| MmMapIoSpace | critical | Highly dangerous - potential for arbitrary code execution, memory corruption, or process termination |
| MmCopyVirtualMemory | critical | Highly dangerous - potential for arbitrary code execution, memory corruption, or process termination |
| MmMapLockedPagesSpecifyCache | critical | Highly dangerous - potential for arbitrary code execution, memory corruption, or process termination |
| MmGetSystemRoutineAddress | high | Potentially dangerous - could be used for privilege escalation or security bypass |
| PsLookupProcessByProcessId | high | Potentially dangerous - could be used for privilege escalation or security bypass |
| ObOpenObjectByPointer | medium | Moderate risk - system modification capability |
| ZwQuerySystemInformation | medium | Moderate risk - system modification capability |
| ObReferenceObjectByHandle | medium | Moderate risk - system modification capability |
| MmUnmapIoSpace | medium | Moderate risk - system modification capability |
| ZwDeleteKey | medium | Moderate risk - system modification capability |
| RtlInitAnsiString | low | Standard kernel API - generally benign |
| ZwClose | low | Standard kernel API - generally benign |
| DbgPrintEx | low | Standard kernel API - generally benign |
| RtlInitUnicodeString | low | Standard kernel API - generally benign |
| KeDelayExecutionThread | low | Standard kernel API - generally benign |
| IofCompleteRequest | low | Standard kernel API - generally benign |
| ZwOpenKey | low | Standard kernel API - generally benign |
| ExAllocatePoolWithTag | low | Standard kernel API - generally benign |
Control codes reachable through the driver dispatch routine. Codes tied to published exploit code are flagged, since they are the primary Bring Your Own Vulnerable Driver (BYOVD) entry points.
| Code | Severity | Transfer | Description |
|---|---|---|---|
| 0x00223417 | high | METHOD_NEITHER | FILE_DEVICE_UNKNOWN Function #3333 |
| 0x002200F0 | medium | METHOD_BUFFERED | FILE_DEVICE_UNKNOWN Function #60 |
| 0x00802494 | medium | METHOD_BUFFERED | FILE_DEVICE_CUSTOM Function #2341 |
| 0x00800F15 | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #965 |
| 0x00802484 | medium | METHOD_BUFFERED | FILE_DEVICE_CUSTOM Function #2337 |
| 0x0080248C | medium | METHOD_BUFFERED | FILE_DEVICE_CUSTOM Function #2339 |
| 0x008024BC | medium | METHOD_BUFFERED | FILE_DEVICE_CUSTOM Function #2351 |
| 0x0080BB05 | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #3777 |
| 0x00806705 | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #2497 |
| 0x0080CF05 | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #961 |
| 0x0080270D | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #2499 |
| 0x0080EC81 | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #2848 |
| 0x0080C481 | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #288 |
| 0x00806EFE | medium | METHOD_OUT_DIRECT | FILE_DEVICE_CUSTOM Function #3007 |
| 0x00220119 | medium | METHOD_IN_DIRECT | FILE_DEVICE_UNKNOWN Function #70 |
| 0xC3503024 | medium | METHOD_BUFFERED | CUSTOM_MSI Function #3081 |
Section layout and Shannon entropy. High entropy in a code section is a packing or encryption indicator.
| Section | Virtual size | Raw size | Entropy | Flags |
|---|---|---|---|---|
| .text | 0xA039 | 0xA200 | 6.42 | CODE, EXEC, READ |
| .rdata | 0x1A60 | 0x1C00 | 5.57 | IDATA, READ |
| .data | 0x0240 | 0x0200 | 0.8 | IDATA, READ, WRITE |
| .pdata | 0x02E8 | 0x0400 | 3.34 | IDATA, READ |
| INIT | 0x0798 | 0x0800 | 4.98 | CODE, EXEC, READ, DISCARD |
| .reloc | 0x0028 | 0x0200 | 0.52 | IDATA, READ, DISCARD |
| Control Flow Guard | Enabled |
|---|---|
| ASLR | Enabled |
| DEP | Enabled |
| Integrity check | Not enforced |
| Mitigation score | 80 / 100 |
| Rule | Severity | Detects |
|---|---|---|
| SUSP_PhysMem | high | Physical memory mapping |
Techniques this driver could enable if loaded by an adversary.
| ID | Technique | Tactic |
|---|---|---|
| T1003 | OS Credential Dumping | Credential Access |
| T1003.001 | OS Credential Dumping: LSASS Memory | Credential Access |
| T1006 | Direct Volume Access | Defense Evasion |
| T1055.001 | Process Injection: DLL Injection | Defense Evasion |
| T1055.012 | Process Hollowing | Defense Evasion |
| T1068 | Exploitation for Privilege Escalation | Privilege Escalation |
| T1211 | Exploitation for Defense Evasion | Defense Evasion |
| T1489 | Service Stop | Impact |
| T1543.003 | Windows Service | Persistence |
| T1553.002 | Subvert Trust Controls: Code Signing | Defense Evasion |
| T1553.006 | Code Signing Policy Modification | Defense Evasion |
| T1562.001 | Impair Defenses: Disable/Modify Tools | Defense Evasion |
| T1569.002 | System Services: Service Execution | Execution |
| T1652 | Device Driver Discovery | Discovery |
Engine angr, status completed, 100 paths explored at a maximum depth of 100. Vulnerability classes reached: 0. Exploitable paths: 0.
Based on DriverShield static and dynamic analysis, NullkD.sys shows some suspicious signals and warrants manual review. Its composite risk score is 58/100 (verdict: suspicious). Always validate findings independently before acting.
NullkD.sys has a DriverShield composite risk score of 58/100, placing it in the suspicious verdict band. SHA256: b966539685ff4373079abc693bc0a298aeb8c57301a8a330c1fb860453787338.
NullkD.sys is a Windows kernel-mode driver (.sys) analyzed by DriverShield for vulnerabilities, BYOVD abuse potential, and malware indicators.
Related: What an IOCTL dispatch code is · How YARA matching feeds the score · BYOVD research index · full driver database · CVE library · code signing atlas