Windows File Protection

Last updated

Windows File Protection (WFP), a sub-system included in Microsoft Windows operating systems of the Windows 2000 and Windows XP era, aims to prevent programs from replacing critical Windows system files. Protecting core system files mitigates problems such as DLL hell with programs and the operating system. Windows 2000, Windows XP and Windows Server 2003 include WFP under the name of Windows File Protection; Windows Me includes it as System File Protection (SFP).

Operation

With Windows File Protection active, replacing or deleting a system file that has no file lock to prevent it getting overwritten causes Windows immediately and silently to restore the original copy of the file. The original version of the file is restored from a cached folder which contains backup copies of these files. The Windows NT family uses the cached folder %WinDir%\System32\Dllcache. Windows Me caches its entire set of compressed cabinet setup files and stores them in the %Systemroot%\Options\Install folder.

WFP covers all files which the operating system installs (such as DLL, EXE, SYS, OCX etc.), protecting them from deletion or from replacement by older versions. The digital signatures of these files are checked using code signing and the signature catalog files stored in the %Systemroot%\system32\CatRoot\{F750E6C3-38EE-11D1-85E5-00C04FC295EE} folder. Only certain operating system components such as the Package Installer (Update.exe) or Windows Installer (Msiexec.exe) can replace these files. Changes made using any other methods in order to replace these files are reverted and the files are silently restored from the cache. If Windows File Protection cannot automatically find the file in the cached folder, it searches the network path or prompts the user for the Windows installation disc to restore the appropriate version of the file.

WFP integrates with the System File Checker (sfc.exe) utility.

Windows Vista and later Windows systems do not include Windows File Protection, but they include Windows Resource Protection which protects files using ACLs. Windows Resource Protection aims to protect core registry keys and values and prevent potentially damaging system configuration changes, besides operating system files.

The non-use of ACLs in Windows File Protection was a design choice: Not only did it allow operation on non-NTFS systems, but it prevented those same "bad" installers from failing completely from a file access error.

Related Research Articles

In computing, DLL Hell is a term for the complications that arise when one works with dynamic-link libraries (DLLs) used with Microsoft Windows operating systems, particularly legacy 16-bit editions, which all run in a single memory space.

Windows 98 Microsoft personal computer operating system released in 1998

Windows 98 is an operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It is the successor to Windows 95, and was released to manufacturing on May 15, 1998, and generally to retail on June 25, 1998. Like its predecessor, it is a hybrid 16-bit and 32-bit monolithic product with the boot stage based on MS-DOS.

Windows Me Personal computer operating system by Microsoft released in 2000

Windows Millennium Edition, or Windows Me, is an operating system produced by Microsoft as part of the Windows 9x family of operating systems. It was the direct successor to Windows 98, and was released to manufacturing on June 19, 2000, with retail sales beginning on September 14, 2000. It was the last Windows version to be based on the Windows 95 kernel and MS-DOS, with its successor Windows XP being based on Microsoft's Windows NT kernel instead.

The Encrypting File System (EFS) on Microsoft Windows is a feature introduced in version 3.0 of NTFS that provides filesystem-level encryption. The technology enables files to be transparently encrypted to protect confidential data from attackers with physical access to the computer.

Windows Registry Database for Microsoft Windows

The Windows Registry is a hierarchical database that stores low-level settings for the Microsoft Windows operating system and for applications that opt to use the registry. The kernel, device drivers, services, Security Accounts Manager, and user interfaces can all use the registry. The registry also allows access to counters for profiling system performance.

An autorun.inf file is a text file that can be used by the AutoRun and AutoPlay components of Microsoft Windows operating systems. For the file to be discovered and used by these component, it must be located in the root directory of a volume. As Windows has a case-insensitive view of filenames, the autorun.inf file can be stored as AutoRun.inf or Autorun.INF or any other case combination.

System Restore System recovery feature in Microsoft Windows

System Restore is a feature in Microsoft Windows that allows the user to revert their computer's state to that of a previous point in time, which can be used to recover from system malfunctions or other problems. First included in Windows Me, it has been included in all following desktop versions of Windows released since, excluding Windows Server. In Windows 10, System Restore is turned off by default and must be enabled by users in order to function. This does not affect personal files such as documents, music, pictures, and videos.

System File Checker (SFC) is a utility in Microsoft Windows that allows users to scan for and restore corruptions in Windows system files.

Windows XP introduced many features not found in previous versions of Windows.

The Windows NT startup process is the process by which Windows NT 4.0, Windows 2000, Windows XP and Windows Server 2003 operating systems initialize. In Windows Vista and later, this process has changed significantly; see Windows Vista startup process for information about what has changed.

In computing ntoskrnl.exe, also known as kernel image, provides the kernel and executive layers of the Microsoft Windows NT kernel space, and is responsible for various system services such as hardware abstraction, process and memory management, thus making it a fundamental part of the system. It contains the cache manager, the executive, the kernel, the security reference monitor, the memory manager, and the scheduler (Dispatcher).

There are a number of security and safety features new to Windows Vista, most of which are not available in any prior Microsoft Windows operating system release.

Temporary Internet Files is a folder on Microsoft Windows which serves as the browser cache for Internet Explorer to cache pages and other multimedia content, such as video and audio files, from websites visited by the user. This allows such websites to load more quickly the next time they are visited.

In computing, cacls and its replacement, icacls, are Microsoft Windows native command line utilities capable of displaying and modifying the security descriptors on folders and files. An access control list is a list of permissions for securable object, such as a file or folder, that controls who can access it. The cacls command is also available on ReactOS.

Windows Vista contains a range of new technologies and features that are intended to help network administrators and power users better manage their systems. Notable changes include a complete replacement of both the Windows Setup and the Windows startup processes, completely rewritten deployment mechanisms, new diagnostic and health monitoring tools such as random access memory diagnostic program, support for per-application Remote Desktop sessions, a completely new Task Scheduler, and a range of new Group Policy settings covering many of the features new to Windows Vista. Subsystem for UNIX Applications, which provides a POSIX-compatible environment is also introduced.

Windows Resource Protection is a feature in Windows Vista that replaces Windows File Protection. It protects registry keys and folders in addition to critical system files. The way it protects resources differs entirely from the method used by Windows File Protection.

Side-by-side assembly technology is a standard for executable files in Windows 98 Second Edition, Windows 2000, and later versions of Windows that attempts to alleviate problems that arise from the use of dynamic-link libraries (DLLs) in Microsoft Windows. Such problems include version conflicts, missing DLLs, duplicate DLLs, and incorrect or missing registration. In side-by-side, Windows stores multiple versions of a DLL in the WinSxS subdirectory of the Windows directory, and loads them on demand. This reduces dependency problems for applications that include a side-by-side manifest.

Architecture of Windows 9x

The Windows 9x series of operating systems refers to the kernel which lies at the heart of Windows 9x. Its architecture is monolithic.

Sality is the classification for a family of malicious software (malware), which infects files on Microsoft Windows systems. Sality was first discovered in 2003 and has advanced over the years to become a dynamic, enduring and full-featured form of malicious code. Systems infected with Sality may communicate over a peer-to-peer (P2P) network to form a botnet for the purpose of relaying spam, proxying of communications, exfiltrating sensitive data, compromising web servers and/or coordinating distributed computing tasks for the purpose of processing intensive tasks. Since 2010, certain variants of Sality have also incorporated the use of rootkit functions as part of an ongoing evolution of the malware family. Because of its continued development and capabilities, Sality is considered to be one of the most complex and formidable forms of malware to date.