Analysis of mmcss.sys: clean verdict, risk score 23/100. 0 YARA matches. SHA256 e5a59b7ba1ba193f. 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 23/100, indicating no notable risk signals (0-29 band).
| Verdict | Clean (23/100) |
| YARA matches | 0 |
| File size | 53248 bytes |
| Analyzed | 2026-03-22 |
| SHA256 | e5a59b7ba1ba193f5b9a69cf7d77343f7c197a3df23d0eaa553d9df765b1e9f2 |
| SHA1 | 86b2ca9d6ec50e2e63236c9939e52b47d1e3cc86 |
| MD5 | e75d0bdeb7df7079cb994dbebb36e94c |
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 | 10.0.19041.3636 (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 | 100 / 100 |
| IOCTL dispatch surface | 21 / 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 |
| PsGetCurrentProcess | low | Standard kernel API - generally benign |
| ZwClose | low | Standard kernel API - generally benign |
| ExAllocatePoolWithTag | low | Standard kernel API - generally benign |
| KeWaitForSingleObject | low | Standard kernel API - generally benign |
| IoDeleteDevice | low | Standard kernel API - generally benign |
| RtlInitUnicodeString | low | Standard kernel API - generally benign |
| IoCreateDevice | low | Standard kernel API - generally benign |
| KeSetEvent | low | Standard kernel API - generally benign |
| KeInitializeEvent | low | Standard kernel API - generally benign |
| ZwQueryValueKey | low | Standard kernel API - generally benign |
| ZwOpenKey | low | Standard kernel API - generally benign |
| ProbeForWrite | low | Standard kernel API - generally benign |
| IofCompleteRequest | low | Standard kernel API - generally benign |
| ZwOpenFile | 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 |
|---|---|---|---|
| 0x00222003 | high | METHOD_NEITHER | FILE_DEVICE_UNKNOWN Function #2048 |
| 0x002200F0 | medium | METHOD_BUFFERED | FILE_DEVICE_UNKNOWN Function #60 |
| 0x002208E9 | medium | METHOD_IN_DIRECT | FILE_DEVICE_UNKNOWN Function #570 |
| 0x0034F63D | medium | METHOD_IN_DIRECT | FILE_DEVICE_DISK Function #3471 |
| 0x00802484 | medium | METHOD_BUFFERED | FILE_DEVICE_CUSTOM Function #2337 |
| 0x008024B4 | medium | METHOD_BUFFERED | FILE_DEVICE_CUSTOM Function #2349 |
| 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 | 0x3BB6 | 0x3C00 | 6.07 | CODE, EXEC, READ |
| .rdata | 0x1B30 | 0x1C00 | 4.66 | IDATA, READ |
| .data | 0x0360 | 0x0200 | 0.37 | IDATA, READ, WRITE |
| .pdata | 0x0B94 | 0x0C00 | 4.49 | IDATA, READ |
| .idata | 0x0AF8 | 0x0C00 | 4.37 | IDATA, READ |
| PAGE | 0x2949 | 0x2A00 | 6.04 | CODE, EXEC, READ |
| INIT | 0x15F0 | 0x1600 | 6.16 | CODE, EXEC, READ, DISCARD |
| INITCONS | 0x065C | 0x0800 | 2.6 | IDATA, READ, DISCARD |
| INITDATA | 0x0048 | 0x0200 | 0.52 | IDATA, READ, WRITE, DISCARD |
| GFIDS | 0x0048 | 0x0200 | 0.6 | IDATA, READ, DISCARD |
| .rsrc | 0x0730 | 0x0800 | 3.12 | IDATA, READ, DISCARD |
| .reloc | 0x0534 | 0x0600 | 4.97 | 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 no_findings, 0 paths explored at a maximum depth of 0. 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 23/100 (verdict: clean). Always validate findings independently before acting.
mmcss.sys has a DriverShield composite risk score of 23/100, placing it in the clean verdict band. SHA256: e5a59b7ba1ba193f5b9a69cf7d77343f7c197a3df23d0eaa553d9df765b1e9f2.
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