HackTheBox - Hard Machines

Comprehensive index of retired HTB Hard-difficulty machines with key techniques and attack path summaries.

Total: 70+ machines Sorted roughly by retirement date (newest first)

Machine Index

# Machine OS Key Techniques Attack Path Summary Writeup
1 DarkZero Windows Cross-Forest Trust Abuse, AD Exploitation Enumerate cross-forest trust relationships, abuse SID history or trust keys for domain admin in foreign forest 0xdf
2 Retire Windows Active Directory, Kerberos Delegation Abuse Enumerate AD for constrained/unconstrained delegation, abuse Kerberos ticket forwarding for DA IppSec
3 Haze Windows Splunk Enterprise RCE, Active Directory Exploit Splunk Enterprise vulnerability for initial access, pivot through AD for domain admin 0xdf
4 Mirage Windows ADCS, Shadow Credentials, Active Directory Enumerate ADCS for vulnerable certificate templates, abuse shadow credentials for lateral movement to DA 0xdf
5 Certificate Windows ADCS Certificate Template Abuse, ESC1/ESC4 Exploit misconfigured ADCS certificate templates (ESC1/ESC4/ESC8), request certificate as DA 0xdf
6 Vintage Windows Pure AD Exploitation, Kerberoasting, Resource-Based Constrained Delegation Kerberoast service accounts, abuse RBCD for lateral movement, DCSync for domain admin 0xdf
7 RustyKey Linux Rust Binary Exploitation, Custom Crypto Reverse Rust binary, exploit memory safety gap in unsafe block, abuse custom key derivation for root 0xdf
8 NanoCorp Linux Custom Protocol Exploitation, Binary Analysis Reverse-engineer custom network protocol, craft malicious packets for RCE, escalate via custom daemon IppSec
9 Fries Linux Web Exploitation, Custom Application Chain Exploit custom web application with multi-step chain, abuse application trust for code execution as root IppSec
10 Tally Windows SharePoint Enumeration, KeePass, SQL Server xp_cmdshell, Rotten Potato Enumerate SharePoint for KeePass DB, SQL Server creds, xp_cmdshell for shell, RottenPotato for SYSTEM 0xdf
11 Bankrobber Windows XSS, SQL Injection, Custom Binary Buffer Overflow Stored XSS to steal admin cookie, XSRF to trigger SQLi, exploit custom banking app binary overflow 0xdf
12 Chainsaw Linux Blockchain Smart Contract Exploitation, IPFS, SUID Binary Exploit vulnerable Solidity smart contract via Ganache, IPFS enumeration, SUID binary path for root 0xdf
13 Sizzle Windows ADCS, SCF File Attack, Kerberoasting, CLM/AppLocker Bypass SCF file in writable share for NTLM relay, certificate-based auth, Kerberoasting, bypass CLM for DCSync 0xdf
14 Reel Windows Phishing via SMTP, AppLocker Bypass, AD ACL Abuse Craft RTF phishing doc via SMTP, bypass AppLocker with HTA, abuse WriteOwner/WriteDACL AD ACLs for DA 0xdf
15 Mantis Windows Active Directory, MS14-068, Kerberos Enumerate IIS/MSSQL for creds, exploit MS14-068 Kerberos PAC vulnerability to forge golden ticket 0xdf
16 Falafel Linux Type Juggling, SQL Injection (Boolean Blind), wget File Write PHP type juggling auth bypass, boolean-based blind SQLi, wget file write exploit for root 0xdf
17 Stacked Linux XSS, AWS LocalStack Exploitation, Lambda Function Abuse XSS in mail to access internal app, exploit LocalStack to create malicious Lambda, container escape 0xdf
18 Oouch Linux OAuth2 CSRF, D-Bus Exploitation, uwsgi Exploitation Chain OAuth CSRF for admin token, D-Bus command injection, exploit uwsgi config for root 0xdf
19 Travel Linux Memcached Poisoning, SSRF, LDAP Admin Abuse SSRF to poison Memcached with serialized PHP, exploit WordPress custom theme, LDAP admin for root 0xdf
20 Patents Linux XXE (Docx Upload), LFI, Custom Binary Exploit XXE via DOCX upload to read files, LFI chain, exploit custom binary with format string for root 0xdf
21 Multimaster Windows SQL Injection (Unicode Bypass), .NET Reversing, AD Group Abuse Unicode-encoded SQLi in API, crack hashes, reverse .NET DLL for creds, abuse AD group membership chain 0xdf
22 Blackfield Windows AS-REP Roasting, BloodHound, Backup Operator Privilege AS-REP roast for initial hash, BloodHound ForceChangePassword, Backup Operators to dump ntds.dit 0xdf
23 Intense Linux SQLi (SQL Truncation), SNMP RCE, Custom Binary Exploitation SQL truncation for admin token, SNMP authenticated RCE, exploit custom SUID with buffer overflow 0xdf
24 Quick Linux QUIC/HTTP3 Protocol, ESI Injection, Race Condition Enumerate QUIC service, ESI injection for SSRF, race condition in ticket system for admin creds 0xdf
25 Undetected Linux Apache Backdoor Analysis, Kernel Module Backdoor Detect and analyze Apache mod_sedbackdoor, trace custom kernel module backdoor, reverse for root creds 0xdf
26 Gofer Linux Gopher SSRF, LibreOffice Macro Phishing, tcpdump Exploit Gopher protocol SSRF via internal proxy, craft phishing doc with LibreOffice macro, tcpdump SUID for root 0xdf
27 MonitorsThree Linux Cacti SQLi, Duplicati Backup Exploitation SQL injection in Cacti for admin access, exploit Duplicati backup service auth bypass for root 0xdf
28 Compiled Linux Gitea, Go Binary Exploitation, Git Hook Abuse Exploit Gitea instance, reverse Go binary for vulnerabilities, abuse Git hooks for code execution as root 0xdf
29 Usage Linux Laravel SQLi (Blind), laravel-admin Custom Exploit Blind SQL injection in Laravel password reset, exploit laravel-admin file upload for shell, monitor cron for root 0xdf
30 Napper Windows Naplistener Malware Analysis, .NET Reversing, Elasticsearch Analyze Naplistener backdoor, reverse .NET implant, extract Elasticsearch secrets for admin 0xdf
31 Visual Windows Gitea, MSBuild/Visual Studio Project RCE, FullPowers Submit malicious VS project to Gitea for build-triggered RCE, FullPowers to restore privileges, GodPotato 0xdf
32 Snoopy Linux DNS Zone Transfer, Bind9 CVE, SSH MitM via DNS Hijack DNS enumeration, exploit Bind9 CVE to update DNS, MitM SSH via DNS redirect, Git hook abuse for root 0xdf
33 Cerberus Windows/Linux Icinga Web CVE, SSSD Exploitation, AD Certificate Abuse Exploit Icinga Web 2 CVE for RCE, pivot Linux to Windows via SSSD secrets, ADCS ESC7 for DA  
34 Vessel Linux PyInstaller Reversing, Node.js Regex ReDoS, PDF Exploitation Reverse PyInstaller binary for creds, ReDoS bypass auth, exploit custom PDF generation for root 0xdf
35 Absolute Windows Active Directory, LDAP Enumeration, Kerberos Relay, Shadow Credentials Image metadata LDAP creds, Kerberos relay attack, shadow credential abuse for DA 0xdf
36 Sekhmet Windows/Linux Kerberos CC Ticket Abuse, ADCS ESC8, Cross-Domain Trust Steal CC ticket from Linux, abuse ADCS ESC8 via NTLM relay, pivot cross-domain for enterprise admin  
37 Scramble Windows Kerberos-Only Auth (no NTLM), Silver Ticket, .NET Deserialization Enumerate with Kerberos only, forge silver ticket for MSSQL, .NET BinaryFormatter deserialization for SYSTEM IppSec
38 Intelligence Windows ITSM PDF Metadata, DNS Record Abuse, GMSA Password Read, Constrained Delegation Extract creds from PDF metadata, abuse DNS records, read GMSA password, constrained delegation for DA 0xdf
39 Writer Linux SQL Injection, Postfix/SMTP Exploitation, apt PreInvoke Union SQLi for file read, SMTP command injection via malicious email handler, apt pre-invoke cron for root 0xdf
40 PivotAPI Windows AS-REP Roasting, MSSQL, Exchange Exploitation, SeManageVolume AS-REP roast, pivot through MSSQL linked servers, abuse Exchange permissions, SeManageVolume for SYSTEM 0xdf
41 Object Windows Active Directory, Jenkins, AD ACL Chain (WriteOwner/GenericWrite) Exploit Jenkins for initial access, enumerate AD ACLs, chain WriteOwner to ForceChangePassword for DA 0xdf
42 APT Windows IPv6, Kerberos, AD Exploitation, NTLM Relay Discover services on IPv6, Kerberos enumeration, NTLM relay to ADCS for certificate-based auth as DA 0xdf
43 Acute Windows XLSX Metadata, PowerShell Web Access, BAT File Exploitation Extract usernames from XLSX metadata, bruteforce PSWA, bat file to add to admin group, WinRM lateral 0xdf
44 Anubis Windows ASP.NET ViewState RCE, Certify/ADCS Exploit insecure ViewState deserialization, enumerate ADCS with Certify, abuse certificate template for DA 0xdf
45 Extension Linux Gitea, Snippet Injection, Browser Extension Exploitation Exploit Gitea for access, inject malicious code into shared snippets, browser extension RCE for root 0xdf
46 Moderators Linux WordPress Custom Plugin Exploit, VNC Password Recovery, hashcat Exploit WP plugin, discover VNC password in config, crack for SSH, hashcat custom rule for root 0xdf
47 RainyDay Linux API Exploitation, Python Pickle Deserialization, Docker Secret Exploit API for initial access, Python Pickle deserialization, Docker secret extraction for root 0xdf
48 Pollution Linux XXE, Redis Exploitation, Prototype Pollution to RCE XXE for internal access, Redis command injection, JavaScript prototype pollution for code execution as root 0xdf
49 Derailed Linux Ruby on Rails WebSocket, Xterm.js Exploitation, openmediavault Rails WebSocket hijacking for admin, Xterm.js injection for shell, openmediavault cron for root 0xdf
50 Sekhmet Windows Kerberos Authentication, ADCS ESC8, Cross-Forest Trust Abuse Kerberos CC ticket, NTLM relay to ADCS ESC8, cross-forest pivot for enterprise admin 0xdf
51 Response Linux HAProxy SSRF, Custom Proxy Chain, LDAP Injection, mTLS Chain SSRF through HAProxy, LDAP injection for creds, mTLS certificate forge for root service 0xdf
52 Carpediem Linux Backdrop CMS, Docker Pivoting, Trudesk, Voip CDR Exploit Backdrop CMS, pivot through Docker network, Trudesk ticket access, CDR analysis for root 0xdf
53 Seventeen Linux Roundcube XSS, Exam Management SQLi, Docker Compose SQLi in exam app, pivot via Roundcube stored XSS, Docker compose abuse for root 0xdf
54 Yummy Linux JWT Forgery, Cron Race Condition, rsync Exploit Forge JWT for admin access, exploit cron race condition, rsync to write authorized_keys as root 0xdf
55 EscapeTwo Windows MSSQL xp_dirtree, NTLM Relay, ADCS ESC4 Capture NTLM hash via xp_dirtree, relay to LDAP, abuse ADCS ESC4 certificate template for DA 0xdf
56 Lantern Linux Blazor .NET RCE, Pivoting, Custom Service Exploit Exploit Blazor application vulnerability, pivot internally, exploit custom service for root 0xdf
57 Resource Linux SSH CA Certificate Abuse, ITDB Exploitation Exploit IT database for SSH CA signing key, forge SSH certificates for admin users, escalate to root 0xdf
58 Observed Linux Gitea, SQL Injection, Container Escape, Kernel Exploit SQLi in Gitea, container escape via privileged container, kernel exploit for root on host IppSec
59 Titanic Linux Gitea Enumeration, Docker Registry, Flask Werkzeug Enumerate Gitea repos, discover Docker registry secrets, exploit Flask debug for RCE, container escape 0xdf
60 Blueprint Windows SharePoint Exploitation, ADCS, Constrained Delegation Exploit SharePoint for initial foothold, ADCS cert abuse, constrained delegation for DA IppSec

Machines by OS

Windows (30+)

Tally, Bankrobber, Sizzle, Reel, Mantis, Multimaster, Blackfield, Napper, Visual, Scramble, Intelligence, PivotAPI, Object, APT, Absolute, Sekhmet, DarkZero, Retire, Haze, Mirage, Certificate, Vintage, Cerberus (hybrid), Acute, Anubis, EscapeTwo, Blueprint

Linux (35+)

Chainsaw, Ellingson, Falafel, Stacked, Oouch, Travel, Patents, Intense, Quick, Undetected, Gofer, MonitorsThree, Compiled, Usage, Snoopy, Vessel, Writer, Fries, NanoCorp, RustyKey, Extension, Moderators, RainyDay, Pollution, Derailed, Response, Carpediem, Seventeen, Yummy, Lantern, Resource, Observed, Titanic


Machines by Technique Category

Active Directory

Machine Specific AD Technique
Sizzle ADCS, SCF File, Kerberoasting, CLM Bypass
Reel Phishing, AppLocker Bypass, AD ACL Abuse
Mantis MS14-068 Kerberos PAC Exploit
Blackfield AS-REP Roasting, BloodHound, Backup Operators
Multimaster Unicode SQLi to AD, Group Membership Chain
Scramble Kerberos-Only Auth, Silver Ticket
Intelligence GMSA Password Read, Constrained Delegation
PivotAPI AS-REP, MSSQL, Exchange, SeManageVolume
Object Jenkins to AD ACL Chain
APT IPv6, NTLM Relay to ADCS
Absolute Kerberos Relay, Shadow Credentials
Sekhmet CC Ticket, ADCS ESC8, Cross-Forest
Certificate ADCS ESC1/ESC4/ESC8
Vintage Kerberoasting, RBCD, DCSync
Mirage ADCS, Shadow Credentials
Haze Splunk + AD Integration
DarkZero Cross-Forest Trust Abuse
Retire Kerberos Delegation Abuse
Cerberus SSSD to AD, ADCS ESC7
EscapeTwo NTLM Relay, ADCS ESC4

ADCS (Active Directory Certificate Services)

Machine ESC Variant
Sizzle Certificate-Based Auth
Certificate ESC1/ESC4/ESC8
Mirage ESC + Shadow Credentials
Sekhmet ESC8 via NTLM Relay
Cerberus ESC7
APT NTLM Relay to ADCS
Anubis Certify Template Abuse
EscapeTwo ESC4

Web Exploitation (Advanced)

Machine Specific Technique
Falafel Type Juggling + Boolean Blind SQLi
Quick QUIC/HTTP3 + ESI Injection
Bankrobber Stored XSS + XSRF + SQLi
Travel Memcached Poisoning + SSRF
Stacked XSS + AWS LocalStack Lambda
Oouch OAuth2 CSRF Chain
Gofer Gopher Protocol SSRF
Pollution XXE + Prototype Pollution to RCE
MonitorsThree Cacti SQLi + Duplicati

Binary Exploitation

Machine Specific Technique
Tally SQL Server + Rotten Potato
Bankrobber Custom Binary Buffer Overflow
Intense Custom SUID Buffer Overflow
Ellingson ROP Chain on SUID Binary
RustyKey Rust Binary Exploitation
NanoCorp Custom Protocol Binary Analysis

Deserialization (Advanced)

Machine Specific Technique
Scramble .NET BinaryFormatter
Anubis ASP.NET ViewState
Patents XXE + Format String
RainyDay Python Pickle
Napper .NET Implant Reversing

Blockchain / Smart Contract

Machine Specific Technique
Chainsaw Solidity Smart Contract Exploit via Ganache

Container / Cloud

Machine Specific Technique
Stacked AWS LocalStack Lambda Abuse
Carpediem Docker Network Pivoting
Visual MSBuild in Gitea + GodPotato
Observed Container Escape + Kernel
Cerberus Linux-to-Windows Pivot via SSSD

SSRF Chains

Machine Specific Technique
Travel SSRF + Memcached Poisoning
Gofer Gopher Protocol SSRF
Quick ESI Injection for SSRF
Response HAProxy SSRF Chain
Pollution XXE + Internal SSRF

Difficulty Comparison: Hard vs Medium

Key differences that make these Hard:

  1. Multi-step chains - Hard machines typically require 3-5 distinct exploits chained together
  2. Custom/obscure protocols - QUIC/HTTP3, gRPC, custom TCP, Gopher protocol
  3. Advanced AD attacks - ADCS, cross-forest trusts, Kerberos delegation, RBCD
  4. Binary exploitation - Custom SUID binaries, buffer overflows, ROP chains
  5. Pivoting required - Multiple network segments, container escapes, hybrid OS environments
  6. Anti-patterns - AppLocker bypass, CLM bypass, WAF evasion, non-standard auth

Writeup References

For each machine, recommended external writeup sources:


Certification Relevance

OSCP (Hard machines that build OSCP skills)

Machine Why
Tally Multi-service enumeration, SQL Server, Potato attack
Blackfield AS-REP, BloodHound, Backup Operators
Falafel SQLi + creative file write

OSEP (Evasion and advanced exploitation)

Machine Why
Reel Phishing + AppLocker bypass
Sizzle CLM bypass + ADCS + Kerberoasting
Object Jenkins + AD ACL chain

CPTS / CRTO (Active Directory focus)

Machine Why
Vintage Pure AD, Kerberoasting, RBCD, DCSync
Certificate Full ADCS exploitation
Intelligence GMSA + Constrained Delegation
Sekhmet Cross-forest + ADCS ESC8
Absolute Shadow Credentials + Kerberos Relay

CRTE (Red Team / Evasion)

Machine Why
Sizzle Full AD chain with evasion
Reel Phishing + AppLocker
APT IPv6 + NTLM relay + ADCS
DarkZero Cross-forest trust abuse