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Openwall GNU/*/Linux (or Owl for short) is a small security-enhanced Linux distribution for servers, appliances, and virtual appliances.
Owl live CDs with remote SSH access are also good for recovering or installing systems (whether with Owl or not). Another secondary use is for operating systems and/or computer security courses, which benefit from the simple structure of Owl and from our inclusion of the complete build environment.

You can read more about the concepts behind Owl (including its features and our approach to security), the architectures we support, the guide on using the Owl build environment, and the installation instructions.

You're encouraged to download Owl, try it out, and provide your feedback to us via the owl-users mailing list (see below).

Owl 3.0 was released in December 2010. It uses a RHEL 5.5-based Linux/OpenVZ kernel and it has optional OpenVZ container-based virtualization integrated. We've since updated to RHEL 5.11-based Linux/OpenVZ kernels and beyond in Owl 3.1-stable.

At this time, we barely maintain Owl, fixing only the most critical vulnerabilities. We also get our other software releases into Owl-current for additional testing. Owl's future is unclear. Many of the security enhancements introduced in Owl live on in ALT Linux distributions.

When you download the ISOs below, please also download iso.mtree and iso.mtree.sign files from the same directory, verify the signature on the iso.mtree file using the iso.mtree.sign file and the PGP key that you obtain from this website, and verify the SHA-1 digests of the ISOs using the iso.mtree file.

Please note that these ISOs require DVD media (once uncompressed, they're slightly beyond the size of a CD).

Download latest stable version (release notes, more mirrors are available):

  • Owl 3.1-stable 2018/07/03 for x86-64 - 588996400 bytes (562 MiB) .iso.gz
    bootable on 64-bit capable machines only (including virtual ones such as QEMU, etc.)
  • Owl 3.1-stable 2018/05/24 for 32-bit x86 ("i686") - 583004816 bytes (556 MiB) .iso.gz
    bootable on Pentium Pro/2/3/4 and Celeron (except for some older Pentium M and Celeron M found in some laptops); Xeon (all kinds); Core, Core 2, and Core i3/i5/i7/i9; Atom; Athlon, Opteron; and many more / all newer x86 CPUs and virtual machines (QEMU, etc.)
    (requires PAE, supports NX bit when present)
Download latest development snapshot (requirements are similar to those of Owl 3.1 above):

The above images include a live system, installable packages, the installer program, as well as full source code and the build environment - everything!

There's a mailing list where you can share your experience with Owl and ask questions. Please be sure to specify an informative message subject whenever you post to the list (that is, something better than "question" or "problem"). To subscribe, enter your e-mail address below or send an empty message to <owl-users-subscribe at>. You will be required to confirm your subscription by "replying" to the automated confirmation request that will be sent to you. You will be able to unsubscribe at any time and we will not use your e-mail address for any other purpose or share it with a third party. However, if you post to the list, other subscribers and those viewing the archives may see your address(es) as specified on your message. The list archive is available locally and via MARC.

Your e-mail address:

A separate mailing list exists for Owl development discussions (that is, if you want to discuss and contribute to the source code). Its archive is available locally. To subscribe, enter your e-mail address below or send an empty message to <owl-dev-subscribe at>.

Your e-mail address:

In addition to the owl-users and owl-dev lists you have the option to direct your comments regarding Owl to us privately via <feedback at>. Potential security issues are to be reported to <security at> and non-security bugs to <bugs at>.

Owl is a registered project with Open Hub and DistroWatch.

Please check out our presentation slides on Owl.

Commercial support for Owl is available, please check out our services.

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