NULL File Extension

Have a problem opening a .NULL file? We collect information about file formats and can explain what NULL files are. Additionally we recommend software suitable for opening or converting such files.

What is the .NULL file type?

In Apple's commercial desktop operating system Mac OS X, the dotted character string ".null" represents a hidden file name, rather than an extension. Along with several other filenames, such as .jupdate, .rserv, and others, it is related to the Flashback malware scam that affects Apple Mac OS X through a Java security hole.

On a Mac OS X system, presence of the .null (.jupdate, etc.) file in the user's home directory is a sign of the Flashback infection. Such file is a Mac OS X executable. Because of the leading dot, it is treated as a hidden file, not visible in Finder's default view. Created in the background on vulnerable Mac OS X systems when a malicious Java-based website is visited, the .null (.jupdate, etc.) file acts as a malware downloader agent that downloads and activates the actual malware code. Flashback is known to steal personal and financial information and send it to remote servers.

The Flashback issue has been addressed by Apple, and patched Java along with automated malware removal tools were released for Mac OS X users. Besides, manual Flashback removal instructions are readily available on the Internet.

In some cases, the .null extension is assigned to various multimedia files, like images or audio, in the course of their processing by online or local applications. Conditioned either by misconfiguration or software bugs, such behavior is abnormal, and the .null extension is just a technical placeholder. If the original file format is known or can be determined, the affected files should be individually or collectively renamed, using their proper file type (e.g., ".jpg" instead of ".null").

Besides, the .null filename extension is used in the SIMMAP (Stochastic Mutational Mapping on Phylogenies) software by J.P.Bollback to denote raw statistics files with null or predictive values generated in the course of a SIMMAP analysis run. In addition to .null files, files with observed values are used; these receive the .obs extension.

Lastly, the .null extension may be assigned to files connected with the so-called NULL device (/dev/null in Unix-like OS'es), a virtual "black-hole" sink for digital data. Such .null files may simply be symbolic links pointing to the /dev/null device.

Software to open or convert NULL files

You can open NULL files with the following programs:
VLC media player
VLC media player by VideoLAN
Miro by Participatory Culture Foundation
BitTorrent by BitTorrent Inc.
WinRAR by win.rar GmbH

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