Pronounced as separate letters, ADS is an acronym for alternate data stream. An ADS is a function of Microsoft Windows New Technology File System (NTFS), in which one file can be embedded in another but remains invisible to other users in Windows Explorer. This means the ADS does not affect the size, function, or display of the main file to which the ADS is attached. ADS was originally introduced in 1993 to ensure file server compatibility with the Macintosh Hierarchical File System (HFS).

Uses of ADS

ADS files may be used for a number of purposes. In legitimate applications, an ADS can be used in a variety of ways, including:

In more malicious circumstances, an ADS can be used to launch a Denial of Service (DOS) attack, embed executable files with viruses and trojan horses, or otherwise store illegal materials/records of illegal activity. As a result, ADS files are a common source of evidence for digital forensic scientists. Fortunately, Windows Vista introduced a native tool for identifying these such files and malware scanners have become attuned to preventing these types of attacks.

Webopedia Staff
Webopedia Staff
Since 1995, more than 100 tech experts and researchers have kept Webopedia’s definitions, articles, and study guides up to date. For more information on current editorial staff, please visit our About page.
Get the Free Newsletter
Subscribe to Daily Tech Insider for top news, trends & analysis
This email address is invalid.
Get the Free Newsletter
Subscribe to Daily Tech Insider for top news, trends & analysis
This email address is invalid.

Related Articles

Virtual Private Network (VPN)

A virtual private network (VPN) encrypts a device's Internet access through a secure server. It is most frequently used for remote employees accessing a...

Gantt Chart

A Gantt chart is a type of bar chart that illustrates a project schedule and shows the dependency between tasks and the current schedule...

Input Sanitization

Input sanitization is a cybersecurity measure of checking, cleaning, and filtering data inputs from users, APIs, and web services of any unwanted characters and...

IT Asset Management Software

IT asset management software (ITAM software) is an application for organizing, recording, and tracking all of an organization s hardware and software assets throughout...


ScalaHosting is a leading managed hosting provider that offers secure, scalable, and affordable...


Human resources information system (HRIS) solutions help businesses manage multiple facets of their...

Best Managed Service Providers...

In today's business world, managed services are more critical than ever. They can...