DiskShadow.exe: The Windows Volume Shadow Copy Service Tool

diskshadow.exe is a command-line tool included in Windows Server operating systems (and some client versions with the necessary features enabled) that exposes the functionality offered by the Volume Shadow Copy Service (VSS). VSS is a technology that allows taking manual or automatic backup copies or snapshots of computer files or volumes, even when they are in use. diskshadow.exe provides a powerful way to interact with VSS, offering more control and flexibility than the graphical user interface (GUI) tools.

Origin and Purpose

diskshadow.exe was introduced with Windows Server 2008 and has been included in subsequent server versions. It's a core component related to data backup and recovery. Its primary purpose is to:

• Create and manage shadow copies: DiskShadow allows you to create, delete, import, export, and expose shadow copies of volumes.
• Script backup operations: It can be used in scripts to automate the process of creating consistent backups, especially for applications that require quiescing (temporarily pausing or modifying I/O activity to ensure data consistency).
• Test and troubleshoot VSS: DiskShadow can be used to diagnose issues with VSS writers and providers, and to verify that shadow copies are being created correctly.
• Perform advanced backup and restore operations: Features like transportable shadow copies (using hardware providers) and differential shadow copies are manageable through DiskShadow.

Is it a Virus? Is it Vulnerable?

diskshadow.exe itself is not a virus. It is a legitimate Microsoft-signed executable. However, like any powerful tool, it can be misused by malicious actors.

Potential Misuse:

• Data Exfiltration: Attackers could potentially use diskshadow.exe to create shadow copies of sensitive data and then exfiltrate those copies. This bypasses typical file access controls, as shadow copies can be accessed even if the original files are locked or in use. This is particularly concerning if the attacker gains elevated privileges.
• Ransomware Preparation: Some ransomware variants use diskshadow.exe (or vssadmin.exe) to delete existing shadow copies before encrypting data. This prevents victims from easily restoring their files from previous versions, making the ransomware attack more effective.
• Living Off the Land: Attackers often prefer to use legitimate, built-in tools like diskshadow.exe (known as "living off the land") to avoid detection by security software. Using a legitimate tool makes it harder to distinguish malicious activity from normal system operations.

Vulnerabilities:

While diskshadow.exe itself is not inherently vulnerable, it interacts with the VSS infrastructure, which can be subject to vulnerabilities. Exploits targeting VSS writers or providers could potentially be leveraged through diskshadow.exe. It's crucial to keep your system updated with the latest security patches to mitigate these risks.

How to Use DiskShadow.exe (Tool Usage)

diskshadow.exe operates in two modes: interactive mode and script mode.

1. Interactive Mode

To enter interactive mode, simply open an elevated command prompt (run as administrator) and type: