Recommended Boot2Root Machines

After some research I created this personal “to do” list of recommended / famous / must-solve Boot2Root machines from Vulnhub and HTB focused mainly on OSCP preparation.
The list is NOT only about machines similar to OSCP. It also includes machines that are way easier or harder than OSCP but are worth solving as and you will definitely learn something new from each one.
PS: HTB machines are categorized by platform Windows/Linux and are sorted by difficulty. OSCP-like machines are reported by users to usually be bellow 5 in the HTB difficulty scale.

Vulnhub Linux Machines

NameDifficulty (My rating)CompletedShort Notes (No spoilers)Recommended writeup
DeRKnStiNK 1Easy - BeginnerYESCTFish, Flags, Webhttps://emaragkos.gr/vulnhub-writeups/vulnhub-derknstink-1-walkthrough/
RICKdiculouslyEasy 1Easy - BeginnerYESReally CTFish, Flags, Enumeration, Web, RCE, Bruteforce, Stego, Fun to solve
https://emaragkos.gr/vulnhub-writeups/rickdiculouslyeasy-1-vulnhub-walkthrough/
covfefe: 1Easy - BeginnerYESCTFish, Flags, Enumeration, Bruteforce, Interesting noob friendly intro to BOFhttps://emaragkos.gr/vulnhub-writeups/vulnhub-covfefe-walkthrough/
Dina: 1.0.1Easy - BeginnerYESWeb, Not really originalhttps://emaragkos.gr/vulnhub-writeups/dina-101-vulnhub-walkthrough/
LazySysAdmin 1.0Easy - BeginnerYESCTFish, Flags, Web, SMBhttps://emaragkos.gr/vulnhub-writeups/lazysysadmin-1-0-vulnhub-walkthrough/
FristiLeaks: 1.3Easy - BeginnerYESCTFish, Enumeration, Web, Cryptography, Interesting PrivEschttps://5h4d0wb0y.github.io/2017-04-10-fristileaks/
HackInOS: 1IntermediateYESOSCP-prep, Awesome machine, Original, Web, Coding, Fuzzing, Bruteforce, Interesting PrivEsc, Pivotinghttps://ethicalhackers.club/hackinos-level-1-vulnhub-complete-walkthrough-guide/
JIS-CTFExtremely EasyYESNot really original, Poor challenges, Bad English, CTFish, Flags, Web, Enumerationhttps://medium.com/@w3rallmachines/jis-ctf-vulnupload-vulnhub-walkthrough-b33ba57b2be0
Lord Of The Root: 1.0.1
Mr-Robot: 1
SkyTower: 1
The Necromancer: 1
Sokar: 1
SolidState: 1
Stapler: 1
Tommy Boy: 1
HackLAB: VulnixIntermediate - AdvancedYESFocuced on enumeration, Many ports, Interesting and more advanced enumeration than most of the machines, Requires solid understanding of Linuxhttps://www.rebootuser.com/?p=988
zico2: 1
WinterMute: 1
Pegasus: 1
Homeless: 1
pWnOS: 2.0 (Pre-Release)
/dev/random: scream
W1R3S: 1.0.1
pluck: 1
OwlNest: 1.0.2
GoldenEye: 1
g0rmint: 1
W34kn3ss: 1
digitalworld.local: MERCY v2
digitalworld.local: BRAVERY
Toppo: 1
Bob: 1.0.1
NullByte: 1
Lin.Security: 1
unknowndevice64: 1
Brainpan: 1
Brainpan: 2
Brainpan: 3
Breach: 1
Breach: 2.1
Breach: 3.0.1
Hackademic: RTB1
Hackademic: RTB2
Kioptrix: Level 1 (#1)Easy - BeginnerYESMeh, not really originalhttps://emaragkos.gr/vulnhub-writeups/kioptrix-level-1-vulnhub-walkthrough/
Kioptrix: Level 1.1 (#2)Easy - BeginnerYESWeb, SQLi, RCEhttps://www.abatchy.com/2016/12/kioptrix-2-walkthrough-vulnhub
Kioptrix: Level 1.2 (#3)
Kioptrix: Level 1.3 (#4)
Kioptrix: 2014 (#5)
SickOs: 1.1Easy - BeginnerYESCreator mentions that "This vm is very similar to labs I faced in OSCP." Personally I found it pretty easy compared to other machines that mention the same thing. CTFish, Enumeration, Web, Not really original except the proxy thing (no spoilers). https://www.youtube.com/watch?v=kkHYPRmS4kw
SickOs: 1.2
billu: b0x
billu: b0x 2
Tr0ll: 1
Tr0ll: 2

Vulnhub Windows Machines

NameDifficulty (My rating)CompletedShort notes (No Spoilers)Recommended writeup
Bobby: 1
/dev/random: scream

HackTheBox Linux Machines

NameDifficulty (HTB rating)CompletedShort Notes (No spoilers)Recommended writeup
Lame2.7
Bashed3.5
Nibbles3.7
Mirai3.8YES
Shocker3.8
Beep3.9
Sense3.9
Poison3.9
Sunday4.1
Valentine4.2
Solidstate4.3
Popcorn4.3
Cronos4.4
Haircut4.7
Nineveh5.4
Node6.2
TartarSauce6.2
Brainfuck6.8
Kotarak6.9

HackTheBox Windows Machines

NameDifficulty (HTB rating)CompletedShort Notes (No spoilers)Recommended writeup
Legacy2.4YESGreat place to start even if this is your first machine ever. As the name says is about a Legacy OS and a good old rockstar of exploits, the infamous ms08_067_netapi.https://www.youtube.com/watch?v=wOeYLZazLGI
Blue2.5YESA really simple machine that shows the power of ms17_010_eternalblue. Another rockstar exploit that you should definitely know how to handle. Nothing fancy here but still a really nice machine for beginners. https://www.youtube.com/watch?v=YRsfX6DW10E
Jerry2.9
Granny3.6
Grandpa3.7
Optimum3.7
Devel3.7
Chatterbox4.0
Bounty4.8
Bastard5.0
Jeeves5.0
Silo5.2
Reel6.1
Bart6.3
Tally6.5