mssmbios.sys - Clean (21/100) - DriverShield Analysis

Analysis of mssmbios.sys: clean verdict, risk score 21/100. 0 YARA matches, 0/75 multi-engine detections. SHA256 b158d81780504ab4. Kernel imports, IOCTL codes, MITRE ATT&CK, and code-signing details.

mssmbios.sys - Analysis Report

DriverShield analyzed the Windows kernel driver mssmbios.sys and assigned a verdict of Clean with a composite risk score of 21/100, indicating no notable risk signals (0-29 band).

Verdict	Clean (21/100)
YARA matches	0
Multi-engine detections	0 / 75
File size	79152 bytes
Code-signing signer	Microsoft Windows
Analyzed	2026-10-11
SHA256	b158d81780504ab412c17bb9db0c710f6ad9c7f2b75e7095c2fc2fc1847dc9a0
SHA1	7ce0caea8cb2e7f02774f5d8d20ff1c45dc3c9f5
MD5	fbe7841da9237bbf30ff6abd65984de7

Driver identity

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

File description	System Management BIOS Driver
Product	BaseBoardVersion
Company	Microsoft Corporation
Original filename	smbios.sys
Internal name	smbios.sys
File version	10.0.26100.1 (WinBuild.160101.0800)
Copyright	© Microsoft Corporation. All rights reserved.

How the 21/100 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	75 / 100
IOCTL dispatch surface	30 / 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 mssmbios.sys, ranked by exploitation relevance.

API	Risk	Why it matters
ZwQuerySystemInformation	medium	Moderate risk - system modification capability
ZwDeleteKey	medium	Moderate risk - system modification capability
ZwSetValueKey	medium	Moderate risk - system modification capability
ZwCreateKey	medium	Moderate risk - system modification capability
ZwClose	low	Standard kernel API - generally benign
ZwOpenKey	low	Standard kernel API - generally benign
RtlInitUnicodeString	low	Standard kernel API - generally benign
IofCompleteRequest	low	Standard kernel API - generally benign
ExAllocatePool2	low	Standard kernel API - generally benign
RtlInitAnsiString	low	Standard kernel API - generally benign
IoCreateDevice	low	Standard kernel API - generally benign
IoDeleteDevice	low	Standard kernel API - generally benign

IOCTL dispatch codes (10)

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
0x9C403FFF	high	METHOD_NEITHER	CUSTOM_LENOVO Function #4095
0x002200F0	medium	METHOD_BUFFERED	FILE_DEVICE_UNKNOWN Function #60
0x0080BF15	medium	METHOD_IN_DIRECT	FILE_DEVICE_CUSTOM Function #4037
0x0022E3E8	medium	METHOD_BUFFERED	FILE_DEVICE_UNKNOWN Function #2298
0x0080BA21	medium	METHOD_IN_DIRECT	FILE_DEVICE_CUSTOM Function #3720
0x00340030	medium	METHOD_BUFFERED	FILE_DEVICE_DISK Function #12
0x00227428	medium	METHOD_BUFFERED	FILE_DEVICE_UNKNOWN Function #3338
0x00227400	medium	METHOD_BUFFERED	FILE_DEVICE_UNKNOWN Function #3328
0x00808D89	medium	METHOD_IN_DIRECT	FILE_DEVICE_CUSTOM Function #866
0x00340398	medium	METHOD_BUFFERED	FILE_DEVICE_DISK Function #230

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	0x3F77	0x4000	6.13	CODE, EXEC, READ
fothk	0x1000	0x1000	0.02	CODE, EXEC, READ
.rdata	0x1364	0x2000	2.98	IDATA, READ
.data	0x0700	0x1000	0.46	IDATA, READ, WRITE
.pdata	0x0558	0x1000	1.77	IDATA, READ
.idata	0x088A	0x1000	2.81	IDATA, READ
PAGE	0x17F2	0x2000	5.09	CODE, EXEC, READ
INIT	0x020D	0x1000	1.21	CODE, EXEC, READ, DISCARD
GFIDS	0x0054	0x1000	0.12	IDATA, READ, DISCARD
.rsrc	0x07B8	0x1000	3.19	IDATA, READ, DISCARD
.reloc	0x0500	0x1000	2.09	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 (8)

Techniques this driver could enable if loaded by an adversary.

ID	Technique	Tactic
T1071	Application Layer Protocol	Command and Control
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
T1569.002	System Services: Service Execution	Execution
T1652	Device Driver Discovery	Discovery

Code-signing chain

Signer	Microsoft Windows
Signer organisation	Microsoft Corporation
Issuer	Microsoft Windows Production PCA 2011
Serial	3300000460CF42A912315F6FB3000000000460
Valid from	2023-11-16 19:20 UTC
Valid until	2024-11-14 19:20 UTC (expired)
Signature validity	Not verified

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

Symbolic execution

Engine angr, status timeout, 64 paths explored at a maximum depth of 64. Vulnerability classes reached: 0. Exploitable paths: 0.

Frequently asked questions about mssmbios.sys

Is mssmbios.sys safe?

Based on DriverShield static and dynamic analysis, mssmbios.sys is assessed as clean, with no notable risk signals. Its composite risk score is 21/100 (verdict: clean). Always validate findings independently before acting.

What is the risk score of mssmbios.sys?

mssmbios.sys has a DriverShield composite risk score of 21/100, placing it in the clean verdict band. SHA256: b158d81780504ab412c17bb9db0c710f6ad9c7f2b75e7095c2fc2fc1847dc9a0.

What is mssmbios.sys?

mssmbios.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