The scfilter cid87d25e32ac0d4ef0b1e0502c6b7dfb77 identifier refers to a Smart Card PnP Class Filter Driver, which, when marked as "patched," indicates that Microsoft security updates have blocked the driver or changed authentication methods, causing hardware to fail. Recent updates, particularly around October 2025, forced a migration from Cryptographic Service Providers (CSP) to Key Storage Providers (KSP), causing widespread compatibility issues. For more details on the authentication issues, visit BleepingComputer. Smart card PnP Class Filter Driver - Windows 11 Service
The report for scfilter cid87d25e32ac0d4ef0b1e0502c6b7dfb77 patched concerns a specific hardware identifier and system driver associated with Smart Card Plug and Play (PnP) services on Microsoft Windows. 1. Component Overview
scfilter.sys: This is the Smart Card PnP Class Filter Driver. Its primary function is to detect and manage smart card readers and virtual smart cards (like YubiKeys) when they are connected to a Windows system.
CID (Container ID): The string cid87d25e32ac0d4ef0b1e0502c6b7dfb77 is a unique Hardware Identifier or Container ID. In Windows, these IDs help the OS group different functional parts of the same physical device together. 2. Status: "Patched"
The term "patched" in this context typically refers to one of two scenarios:
Security Vulnerability Fix: Recent Windows security updates have addressed vulnerabilities within the Windows Cryptographic services and related drivers like scfilter.sys. If a report lists this ID as "patched," it usually indicates the system has received the necessary updates to prevent exploits targeting smart card redirection or authentication bypass.
Driver Modification: In some advanced troubleshooting or malware remediation cases, "patched" may refer to a registry entry or driver file that has been modified to fix compatibility issues or remove malicious hooks. 3. Common Contexts
Malware Scans: This specific CID frequently appears in system logs from tools like Farbar Recovery Scan Tool (FRST) or Malwarebytes. It is often listed under the "Services" or "Drivers" section to confirm the integrity of the Smart Card filter.
YubiKey/Smart Card Troubleshooting: Organizations often use this ID to identify and manage YubiKey Smart Card Minidrivers. Administrators may block or allow this specific ID via Windows Group Policy to control device installation. 4. Recommended Action If you are seeing this in a security report:
Verify Source: Ensure the "patched" status comes from an official Windows Update or a reputable security tool like Malwarebytes.
Check Windows Update: Confirm your system is running the latest security patches for Windows Cryptographic Services to ensure scfilter.sys is protected. If you'd like, I can help you: Analyze a specific log file where this ID appeared.
Provide steps to verify if your scfilter.sys driver is up to date. scfilter cid87d25e32ac0d4ef0b1e0502c6b7dfb77 patched
Explain how to block or allow this device ID via Group Policy. Smart card basic troubleshooting - Yubico Support
To prevent the YubiKey Smart Card Minidriver from being reinstalled after removal, it can be blocked via the Windows Group Policy.
This keyword refers to a specific Windows Smart Card Mini-driver Filter (SCFilter)
and a unique Hardware ID (CID) associated with a card reader or driver instance.
Understanding "scfilter cid87d25e32ac0d4ef0b1e0502c6b7dfb77 patched"
The term scfilter is a built-in Windows component used to manage Smart Card communications. When a smart card (like a CAC for military personnel or a corporate security card) is inserted, Windows uses the scfilter.sys driver to identify it. The "patched" status likely refers to one of two scenarios:
Driver Compatibility Fixes: Recent Windows updates (notably in 2024 and 2025) have caused conflicts with smart card readers, leading to authentication errors or "unrecognized hardware" messages. Users searching for a "patched" version are often looking for the specific registry fix or driver update that restores functionality.
Security Vulnerability Remediation: Vulnerabilities in Windows mini-filter drivers—such as CVE-2025-62221 (a privilege escalation flaw)—have required urgent patching to prevent local users from gaining SYSTEM privileges. Troubleshooting and Patching Steps
If you are experiencing issues with this specific CID or your card reader is being blocked, follow these standard remediation steps: 1. Apply the Registry "Patch"
For many users on Windows 11, authentication issues are caused by a security fix for CVE-2024-30098. Microsoft recommends this registry adjustment if you encounter smart card failures: Open Registry Editor (search for regedit).
Navigate to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography\Calais. Remediation & Recommendations
Find or create a DWORD (32-bit) value named DisableCapiOverrideForRSA.
Set the value to 0 to allow standard cryptographic operations. 2. Update via Windows Update
Ensure your system is running the latest security patches. Many "scfilter" bugs are resolved by cumulative updates.
Go to Settings > Windows Update and select Check for updates.
Look for "Optional Updates" as these often contain specific hardware driver patches for smart card readers. 3. Driver Reinstallation (The "Clean" Patch)
If the hardware CID is still causing errors, you may need to force Windows to use the standard WUDF (Windows User Mode Driver Framework) driver:
Open Device Manager and find your card reader under "Smart card readers". Right-click and select Update driver .
Choose "Browse my computer for drivers" > "Let me pick from a list of available drivers". Select the generic Microsoft Usbccid Smartcard Reader (WUDF) . Security Context
The "patched" status is critical because attackers have historically used trusted drivers to bypass security systems. Always download patches directly from official sources like the Microsoft Security Response Center or your hardware manufacturer's official support page, such as MilitaryCAC for specific SCR reader drivers.
Are you currently facing a specific error code or authentication failure with your smart card reader?
The string "scfilter cid87d25e32ac0d4ef0b1e0502c6b7dfb77 patched" Immediate Action: Update the SCFilter driver to the
does not refer to a formal academic paper or a documented security vulnerability in standard databases. Instead, it appears to be a specific identifier found in Windows system logs antivirus scan reports (like Norton Power Eraser or Farbar Recovery Scan Tool). Microsoft Learn Context of the Term scfilter.sys : This is the legitimate Smart Card PnP Class Filter Driver
built into Windows. It handles the communication between the OS and smart card readers. : Stands for Card Identifier
. The long alphanumeric string following it is a unique hardware or session ID associated with a specific smart card or its driver instance.
: In the context of a system report, this typically indicates that a software update (patch) was applied to the driver or that a security tool has "fixed" an entry related to it. Microsoft Learn Why You Might See This
If you are seeing this in a security report, it is often one of the following: False Positive : Security tools like
sometimes flag system drivers as suspicious due to their deep access to the kernel, even when they are safe. Driver Update
: A recent Windows Update might have replaced an older version of scfilter.sys
with a patched version to fix compatibility issues, such as those reported in Windows 11 : Troubleshooting tools like Farbar Recovery Scan Tool (FRST)
often list active drivers and their status (e.g., "patched" or "running"). Recommended Action
If you are looking for this because of a system error (like a BSOD) or a virus scan:
Smart Card Plug and Play - Windows drivers | Microsoft Learn
SCFilter.sys. The binary should reflect the compilation changes associated with CID 87d25e32ac0d4ef0b1e0502c6b7dfb77.1. The Vulnerability The unpatched version of SCFilter contained a flaw in how it processed certain I/O control (IOCTL) messages. Specifically, the driver failed to properly validate the size of the input buffer passed by user-mode applications.
SCFilterDispatchDeviceControl routine.2. The Patch (CID 87d25e32ac0d4ef0b1e0502c6b7dfb77) The patch introduces rigorous boundary checks before the driver processes any payload data.
ProbeForRead validation for all user-mode input buffers.InputBufferLength aligns with the expected structure size defined in the driver's API.87d25e32ac0d4ef0b1e0502c6b7dfb77 is not present in the driver binary metadata.
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