Vulnerable Operating Systems
21LTRhttps://21ltr.com/scenes/
Damn Vulnerable Linuxhttps://sourceforge.net/projects/virtualhacking/files/os/dvl/
exploit-exercises – nebula, protostar, fusionhttps://exploit-exercises.com/download
heorot: DE-ICE, hackerdemiahttps://hackingdojo.com/downloads/iso/De-ICE_S1.100.iso
https://hackingdojo.com/downloads/iso/De-ICE_S1.110.iso
https://hackingdojo.com/downloads/iso/De-ICE_S1.120.iso
https://hackingdojo.com/downloads/iso/De-ICE_S2.100.iso
hackerdemia – https://hackingdojo.com/downloads/iso/De-ICE_S1.123.iso
Holynixhttps://sourceforge.net/projects/holynix/files/
Kioptrixhttps://www.kioptrix.com/blog/
LAMPSecurityhttps://sourceforge.net/projects/lampsecurity/
Metasploitablehttps://sourceforge.net/projects/virtualhacking/files/os/metasploitable/
neutronstarhttps://neutronstar.org/goatselinux.html
PenTest Laboratoryhttps://pentestlab.org/lab-in-a-box/
Pentester Labhttps://www.pentesterlab.com/exercises
pWnOShttps://www.pwnos.com/
RebootUser Vulnixhttps://www.rebootuser.com/?page_id=1041
SecGame # 1: Sauronhttps://sg6-labs.blogspot.co.uk/2007/12/secgame-1-sauron.html
scriptjunkie.ushttps://www.scriptjunkie.us/2012/04/the-hacker-games/
UltimateLAMPhttps://www.amanhardikar.com/mindmaps/practice-links.html
TurnKey Linuxhttps://www.turnkeylinux.org/
Bitnamihttps://bitnami.com/stacks
Elastic Serverhttps://elasticserver.com
OS Boxeshttps://www.osboxes.org
VirtualBoxeshttps://virtualboxes.org/images/
VirtualBox Virtual Applianceshttps://virtualboximages.com/
CentOShttps://www.centos.org/
Default Windows Clientshttps://www.microsoft.com/en-us/evalcenter/evaluate-windows-10-enterprise 
https://dev.windows.com/en-us/microsoft-edge/tools/vms/
Default Windows Serverhttps://www.microsoft.com/en-us/evalcenter/evaluate-windows-server-technical-preview
Default VMWare vSpherehttps://www.vmware.com/products/vsphere/