vmstorfl.sys - Clean (17/100) - DriverShield Analysis

Analysis of vmstorfl.sys: clean verdict, risk score 17/100. 0 YARA matches. SHA256 c7338aad412aa555. Kernel imports, IOCTL codes, MITRE ATT&CK, and code-signing details.

vmstorfl.sys - Analysis Report

DriverShield analyzed the Windows kernel driver vmstorfl.sys and assigned a verdict of Clean with a composite risk score of 17/100, indicating no notable risk signals (0-29 band).

Verdict	Clean (17/100)
YARA matches	0
File size	55272 bytes
Code-signing signer	Microsoft Windows
Analyzed	2026-03-22
SHA256	c7338aad412aa555a2cd3bcb601ae884daa8dd7f40faed5c1e196c1815505497
SHA1	f68e0663d46954524dba95b3f661722ecad10028
MD5	76448c71a0981f1b71d86f979770295d

Driver identity

Version resource data embedded in the vmstorfl.sys PE header, as extracted by the analysis engine.

File description	Virtual Storage Filter Driver
Product	Microsoft® Windows® Operating System
Company	Microsoft Corporation
Original filename	vmstorfl.sys
Internal name	vmstorfl.sys
File version	10.0.19041.3636 (WinBuild.160101.0800)
Copyright	© Microsoft Corporation. All rights reserved.

How the 17/100 score breaks down

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	45 / 100
IOCTL dispatch surface	39 / 100
Known-vulnerable corpus	0 / 100
Code-signing state	80 / 100
Packing and entropy	0 / 100
Dynamic behaviour	0 / 100
CVE cross-reference	0 / 100

Kernel imports (12)

Kernel-mode APIs resolved from the Import Address Table of vmstorfl.sys, ranked by exploitation relevance.

API	Risk	Why it matters
MmGetSystemRoutineAddress	high	Potentially dangerous - could be used for privilege escalation or security bypass
KeBugCheckEx	medium	Moderate risk - system modification capability
IofCompleteRequest	low	Standard kernel API - generally benign
ExAllocatePool	low	Standard kernel API - generally benign
KeSetEvent	low	Standard kernel API - generally benign
DbgPrintEx	low	Standard kernel API - generally benign
KeInitializeEvent	low	Standard kernel API - generally benign
IoBuildDeviceIoControlRequest	low	Standard kernel API - generally benign
DbgPrint	low	Standard kernel API - generally benign
ExAllocatePoolWithTag	low	Standard kernel API - generally benign
RtlInitUnicodeString	low	Standard kernel API - generally benign
KeWaitForSingleObject	low	Standard kernel API - generally benign

IOCTL dispatch codes (13)

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
0x0080850F	high	METHOD_NEITHER	FILE_DEVICE_CUSTOM Function #323
0x0080AF3B	high	METHOD_NEITHER	FILE_DEVICE_CUSTOM Function #3022
0x0080BE3B	high	METHOD_NEITHER	FILE_DEVICE_CUSTOM Function #3982
0x002200F0	medium	METHOD_BUFFERED	FILE_DEVICE_UNKNOWN Function #60
0x00349F0D	medium	METHOD_IN_DIRECT	FILE_DEVICE_DISK Function #1987
0x0080B7E8	medium	METHOD_BUFFERED	FILE_DEVICE_CUSTOM Function #3578
0x00808F89	medium	METHOD_IN_DIRECT	FILE_DEVICE_CUSTOM Function #994
0x0080EC81	medium	METHOD_IN_DIRECT	FILE_DEVICE_CUSTOM Function #2848
0x0034011D	medium	METHOD_IN_DIRECT	FILE_DEVICE_DISK Function #71
0x0022B841	medium	METHOD_IN_DIRECT	FILE_DEVICE_UNKNOWN Function #3600
0x0080A789	medium	METHOD_IN_DIRECT	FILE_DEVICE_CUSTOM Function #2530
0x0080249C	medium	METHOD_BUFFERED	FILE_DEVICE_CUSTOM Function #2343
0x003403AC	medium	METHOD_BUFFERED	FILE_DEVICE_DISK Function #235

PE sections

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	0x3CA9	0x3E00	6.17	CODE, EXEC, READ
.rdata	0x0F18	0x1000	5.14	IDATA, READ
.data	0x0440	0x0200	0.97	IDATA, READ, WRITE
.pdata	0x03B4	0x0400	4.01	IDATA, READ
.idata	0x0ED2	0x1000	4.41	IDATA, READ
PAGE	0x16A4	0x1800	5.94	CODE, EXEC, READ
INIT	0x02AA	0x0400	4.62	CODE, EXEC, READ, DISCARD
GFIDS	0x0080	0x0200	1.13	IDATA, READ, DISCARD
.rsrc	0x2678	0x2800	3.58	IDATA, READ, DISCARD
.reloc	0x03F0	0x0400	5.69	IDATA, READ, DISCARD

Exploit mitigations

Control Flow Guard	Enabled
ASLR	Enabled
DEP	Enabled
Integrity check	Not enforced
Mitigation score	85 / 100

CFG Enabled - Control Flow Guard is active - indirect calls are validated against a bitmap of valid targets at runtime.
ASLR Enabled - Address Space Layout Randomization is active - base address is randomized on each load.
DEP/NX Enabled - Data Execution Prevention is active - non-executable pages cannot be executed.
Expired Certificate - The driver is signed but the certificate has expired. Windows may still load it depending on revocation policy.

MITRE ATT&CK techniques (5)

Techniques this driver could enable if loaded by an adversary.

ID	Technique	Tactic
T1071	Application Layer Protocol	Command and Control
T1211	Exploitation for Defense Evasion	Defense Evasion
T1543.003	Windows Service	Persistence
T1553.002	Subvert Trust Controls: Code Signing	Defense Evasion
T1652	Device Driver Discovery	Discovery

Code-signing chain

Signer	Microsoft Windows
Signer organisation	Microsoft Corporation
Issuer	Microsoft Windows Production PCA 2011
Serial	330000041331BC198807A90774000000000413
Valid from	2023-02-03 00:05 UTC
Valid until	2024-02-01 00:05 UTC (expired)
Signature validity	Not verified

Certificate revision: 0x0200
Certificate type: PKCS#7
Chain: Microsoft Windows Production PCA 2011

Symbolic execution

Engine angr, status no_findings, 0 paths explored at a maximum depth of 0. Vulnerability classes reached: 0. Exploitable paths: 0.

Frequently asked questions about vmstorfl.sys

Is vmstorfl.sys safe?

Based on DriverShield static and dynamic analysis, vmstorfl.sys is assessed as clean, with no notable risk signals. Its composite risk score is 17/100 (verdict: clean). Always validate findings independently before acting.

What is the risk score of vmstorfl.sys?

vmstorfl.sys has a DriverShield composite risk score of 17/100, placing it in the clean verdict band. SHA256: c7338aad412aa555a2cd3bcb601ae884daa8dd7f40faed5c1e196c1815505497.

What is vmstorfl.sys?

vmstorfl.sys is a Windows kernel-mode driver (.sys) analyzed by DriverShield for vulnerabilities, BYOVD abuse potential, and malware indicators. It is code-signed by Microsoft Windows.

Related: Other drivers signed by Microsoft Windows · What an IOCTL dispatch code is · BYOVD research index · full driver database · CVE library · code signing atlas