Analysis of circlass.sys: clean verdict, risk score 15/100. 0 YARA matches. SHA256 564fa08c5bec6daf. Kernel imports, IOCTL codes, MITRE ATT&CK, and code-signing details.
DriverShield analyzed the Windows kernel driver circlass.sys and assigned a verdict of Clean with a composite risk score of 15/100, indicating no notable risk signals (0-29 band).
| Verdict | Clean (15/100) |
| YARA matches | 0 |
| File size | 52224 bytes |
| Analyzed | 2026-03-22 |
| SHA256 | 564fa08c5bec6daf1a83c80c9139a6e1aa7e05d251db3ba379b57c9fdae83e1b |
| SHA1 | 89c772a291ac5097a741ac0d240358c322c5b3d5 |
| MD5 | 115cc1e142ce29c9006d59943108df47 |
Version resource data embedded in the circlass.sys PE header, as extracted by the analysis engine.
| File description | Consumer IR Class Driver for eHome |
|---|---|
| Product | Microsoft® Windows® Operating System |
| Company | Microsoft Corporation |
| Original filename | circlass.sys |
| Internal name | circlass.sys |
| File version | 10.0.19041.1 (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 | 48 / 100 |
| IOCTL dispatch surface | 27 / 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 circlass.sys, ranked by exploitation relevance.
| API | Risk | Why it matters |
|---|---|---|
| MmGetSystemRoutineAddress | high | Potentially dangerous - could be used for privilege escalation or security bypass |
| ZwSetValueKey | medium | Moderate risk - system modification capability |
| ZwOpenKey | low | Standard kernel API - generally benign |
| DbgPrintEx | low | Standard kernel API - generally benign |
| ZwClose | low | Standard kernel API - generally benign |
| RtlInitUnicodeString | low | Standard kernel API - generally benign |
| ExFreePool | low | Standard kernel API - generally benign |
| ExAllocatePoolWithTag | low | Standard kernel API - generally benign |
| ZwQueryValueKey | 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 |
|---|---|---|---|
| 0x00808D8B | high | METHOD_NEITHER | FILE_DEVICE_CUSTOM Function #866 |
| 0x0080958B | high | METHOD_NEITHER | FILE_DEVICE_CUSTOM Function #1378 |
| 0x002200F0 | medium | METHOD_BUFFERED | FILE_DEVICE_UNKNOWN Function #60 |
| 0x0080BB05 | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #3777 |
| 0x0080BD89 | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #3938 |
| 0x0080BB15 | medium | METHOD_IN_DIRECT | FILE_DEVICE_CUSTOM Function #3781 |
| 0x0022D3E8 | medium | METHOD_BUFFERED | FILE_DEVICE_UNKNOWN Function #1274 |
| 0x00340305 | medium | METHOD_IN_DIRECT | FILE_DEVICE_DISK Function #193 |
| 0x003403AC | medium | METHOD_BUFFERED | FILE_DEVICE_DISK Function #235 |
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 | 0x8B6A | 0x8C00 | 6.19 | CODE, EXEC, READ |
| .rdata | 0x17D8 | 0x1800 | 5.02 | IDATA, READ |
| .data | 0x0518 | 0x0200 | 1.63 | IDATA, READ, WRITE |
| .pdata | 0x0498 | 0x0600 | 3.5 | IDATA, READ |
| .idata | 0x058C | 0x0600 | 4.21 | IDATA, READ |
| PAGE | 0x04BE | 0x0600 | 5.27 | CODE, EXEC, READ |
| INIT | 0x0036 | 0x0200 | 0.87 | CODE, EXEC, READ, DISCARD |
| GFIDS | 0x0064 | 0x0200 | 0.89 | IDATA, READ, DISCARD |
| .rsrc | 0x0420 | 0x0600 | 2.45 | IDATA, READ, DISCARD |
| .reloc | 0x04F4 | 0x0600 | 5.04 | 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 |
|---|---|---|
| T1211 | Exploitation for Defense Evasion | Defense Evasion |
| T1543.003 | Windows Service | Persistence |
| T1553.002 | Subvert Trust Controls: Code Signing | Defense Evasion |
| T1553.006 | Code Signing Policy Modification | Defense Evasion |
| 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, circlass.sys is assessed as clean, with no notable risk signals. Its composite risk score is 15/100 (verdict: clean). Always validate findings independently before acting.
circlass.sys has a DriverShield composite risk score of 15/100, placing it in the clean verdict band. SHA256: 564fa08c5bec6daf1a83c80c9139a6e1aa7e05d251db3ba379b57c9fdae83e1b.
circlass.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