Analysis of mmcss.sys: clean verdict, risk score 26/100. 0 YARA matches, 0/76 multi-engine detections. SHA256 f04f54f31221fb21. Kernel imports, IOCTL codes, MITRE ATT&CK, and code-signing details.
DriverShield analyzed the Windows kernel driver mmcss.sys and assigned a verdict of Clean with a composite risk score of 26/100, indicating no notable risk signals (0-29 band).
| Verdict | Clean (26/100) |
| YARA matches | 0 |
| Multi-engine detections | 0 / 76 |
| File size | 94208 bytes |
| Analyzed | 2026-03-23 |
| SHA256 | f04f54f31221fb21b0695a20fa04d4a43859408b8a026d7f736a5e76096a31b2 |
| SHA1 | 112c5d4ab7656b84f04c93893f808190fe5f44c9 |
| MD5 | 8b4813b89d91f724b3c1a1e02e7ad9c2 |
Version resource data embedded in the mmcss.sys PE header, as extracted by the analysis engine.
| File description | MMCSS Driver |
|---|---|
| Product | Microsoft® Windows® Operating System |
| Company | Microsoft Corporation |
| Original filename | mmcss.sys |
| Internal name | mmcss.sys |
| File version | 10.0.26100.7309 (WinBuild.160101.0800) |
| Copyright | © Microsoft Corporation. All rights reserved. |
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 | 0 / 100 |
| Dangerous kernel imports | 93 / 100 |
| IOCTL dispatch surface | 51 / 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 mmcss.sys, ranked by exploitation relevance.
| API | Risk | Why it matters |
|---|---|---|
| MmGetSystemRoutineAddress | high | Potentially dangerous - could be used for privilege escalation or security bypass |
| PsSetCreateThreadNotifyRoutine | medium | Moderate risk - system modification capability |
| ZwQuerySystemInformation | medium | Moderate risk - system modification capability |
| ProbeForWrite | low | Standard kernel API - generally benign |
| ZwOpenKey | low | Standard kernel API - generally benign |
| IoCreateDevice | low | Standard kernel API - generally benign |
| RtlInitUnicodeString | low | Standard kernel API - generally benign |
| KeInitializeEvent | low | Standard kernel API - generally benign |
| IofCompleteRequest | low | Standard kernel API - generally benign |
| KeSetEvent | low | Standard kernel API - generally benign |
| ZwOpenFile | low | Standard kernel API - generally benign |
| ExAllocatePool2 | low | Standard kernel API - generally benign |
| KeWaitForSingleObject | low | Standard kernel API - generally benign |
| ZwQueryValueKey | low | Standard kernel API - generally benign |
| ZwClose | low | Standard kernel API - generally benign |
| IoDeleteDevice | low | Standard kernel API - generally benign |
| PsGetCurrentProcess | 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 |
|---|---|---|---|
| 0x002200F0 | medium | METHOD_BUFFERED | FILE_DEVICE_UNKNOWN Function #60 |
| 0x00807F05 | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #4033 |
| 0x0080B30D | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #3267 |
| 0x00807F0D | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #4035 |
| 0x0080872D | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #459 |
| 0x00808F05 | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #961 |
| 0x0080004D | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #19 |
| 0x008024B4 | medium | METHOD_BUFFERED | FILE_DEVICE_CUSTOM Function #2349 |
| 0x0080249C | medium | METHOD_BUFFERED | FILE_DEVICE_CUSTOM Function #2343 |
| 0x00802484 | medium | METHOD_BUFFERED | FILE_DEVICE_CUSTOM Function #2337 |
| 0x0022BE05 | medium | METHOD_IN_DIRECT | FILE_DEVICE_UNKNOWN Function #3969 |
| 0x0022F981 | medium | METHOD_IN_DIRECT | FILE_DEVICE_UNKNOWN Function #3680 |
| 0x00802500 | medium | METHOD_BUFFERED | FILE_DEVICE_CUSTOM Function #2368 |
| 0x0022BE0A | medium | METHOD_OUT_DIRECT | FILE_DEVICE_UNKNOWN Function #3970 |
| 0x0080BB89 | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #3810 |
| 0x00223D00 | medium | METHOD_BUFFERED | FILE_DEVICE_UNKNOWN Function #3904 |
| 0x0034037C | medium | METHOD_BUFFERED | FILE_DEVICE_DISK Function #223 |
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 | 0x52B7 | 0x6000 | 5.6 | CODE, EXEC, READ |
| fothk | 0x1000 | 0x1000 | 0.03 | CODE, EXEC, READ |
| .rdata | 0x1918 | 0x2000 | 3.85 | IDATA, READ |
| .data | 0x0458 | 0x1000 | 0.06 | IDATA, READ, WRITE |
| .pdata | 0x0B1C | 0x1000 | 3.49 | IDATA, READ |
| .idata | 0x0E78 | 0x1000 | 4.1 | IDATA, READ |
| PAGE | 0x2E7E | 0x3000 | 6.02 | CODE, EXEC, READ |
| INIT | 0x1623 | 0x2000 | 4.92 | CODE, EXEC, READ, DISCARD |
| INITCONS | 0x065C | 0x1000 | 1.52 | IDATA, READ, DISCARD |
| INITDATA | 0x0048 | 0x1000 | 0.11 | IDATA, READ, WRITE, DISCARD |
| GFIDS | 0x0064 | 0x1000 | 0.15 | IDATA, READ, DISCARD |
| .rsrc | 0x0730 | 0x1000 | 1.78 | IDATA, READ, DISCARD |
| .reloc | 0x06D8 | 0x1000 | 2.73 | IDATA, READ, DISCARD |
| Control Flow Guard | Enabled |
|---|---|
| ASLR | Enabled |
| DEP | Enabled |
| Integrity check | Not enforced |
| Mitigation score | 80 / 100 |
Techniques this driver could enable if loaded by an adversary.
| ID | Technique | Tactic |
|---|---|---|
| T1014 | Rootkit | Defense Evasion |
| T1112 | Modify Registry | Defense Evasion |
| T1211 | Exploitation for Defense Evasion | Defense Evasion |
| T1543.003 | Windows Service | Persistence |
| T1547.001 | Registry Run Keys | Persistence |
| T1553.002 | Subvert Trust Controls: Code Signing | Defense Evasion |
| T1553.006 | Code Signing Policy Modification | Defense Evasion |
| T1562.006 | Indicator Blocking | Defense Evasion |
| T1564.001 | Hidden Files and Directories | Defense Evasion |
| T1569.002 | 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, mmcss.sys is assessed as clean, with no notable risk signals. Its composite risk score is 26/100 (verdict: clean). Always validate findings independently before acting.
mmcss.sys has a DriverShield composite risk score of 26/100, placing it in the clean verdict band. SHA256: f04f54f31221fb21b0695a20fa04d4a43859408b8a026d7f736a5e76096a31b2.
mmcss.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 · BYOVD research index · full driver database · CVE library · code signing atlas