Infiltr8: The Red-Book
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  • The Red-Book
  • Red-Teaming
    • Reconnaissance
      • DNS Enumeration
      • Subdomains enumeration
      • Email Harvesting
      • Host Discovery
      • TCP/UDP Service Scanning
      • Vulnerability Scanning
      • Google Dorks
      • GitHub Recon
      • Files Metadata
      • 🛠️Maltego
      • 🛠️Specialized Search Engines
    • Execution
      • Code & Process Injection
        • Loading .NET Reflective Assembly
        • Loading .NET Assembly from Windows Script Hosting
        • Process Hollowing
        • WndProc Callback Shellcode Execution
        • Fibers Shellcode Execution
        • Vector Exception Handler Shellcode Execution
        • NtQueueApcThread & NtTestAlert Shellcode Execution
        • Thread Pool Callback Shellcode Execution
        • Module Stomping Shellcode Injection
        • Remote .NET Assembly Loading through WaaSRemediation DCOM Abuse
        • 🛠️DLL Injection
        • 🛠️CreateRemoteThread Injection
        • 🛠️Reflective DLL Injection
        • 🛠️NtMapViewOfSection Injection
        • 🛠️SetWindowHookEx Injection
        • 🛠️PoolParty
        • 🛠️MockingJay
      • Code Execution
        • CMSTP
        • MSBuild
        • MSHTA
        • Microsoft Office Execution
        • Windows Script Host (WSH)
        • Outlook Home Page Abuse (Specula)
        • Powershell Without Powershell.exe
        • RegSrv32
        • Scheduled Tasks
        • Services
        • Windows Library Files
        • HTML Help Files
        • WMI
        • Script Exploits
        • 🛠️Sliver
    • Initial Access
      • Network Services
      • Password Attacks
      • Phishing
        • HTML Smuggling
        • Phishing with Calendars (.ICS Files)
        • Phishing With Microsoft Office
          • MS Office - VBA (Macros)
          • MS Office - RTF Files RCE
          • MS Office - Custom XML parts
          • 🛠️MS Office - Excel 4.0 (XLM) Macros
          • 🛠️MS Office - VBA Stomping
          • 🛠️MS Office - Remote Dotm Template Injection
        • 🛠️Phishing via Proxy
          • Adversary in the Middle (AitM) Phishing
            • EvilGoPhish
            • Evilginx
            • Muraena
            • Modlishka
          • Browser in the Middle (BitM) Phishing
            • cuddlephish
            • EvilnoVNC
    • Persistence
      • Active Directory
      • Windows
        • Accessibility features Backdoor
        • AEDebug Keys Persistence
        • Image File Execution Options (IFEO) Persistence
        • Logon Triggered Persistence
        • LSA Persistence
          • Security Support Provider DLLs
          • Authentication Package
        • Natural Language 6 DLLs Persistence
        • Run Keys Persistence
        • Winlogon Persistence
        • WMI Event Subscription Persistence
      • Linux
        • SSH for Persistence
        • GSocket for Persistence
        • 🛠️Udev rules
    • Defense Evasion
      • Endpoint Detection Respons (EDR) Bypass
        • Bring Your Own Vulnerable Driver (BYOVD)
        • Safe Mode With Networking
        • Windows Defender Application Control (WDAC): Killing EDR
        • 🛠️Load Unsigned Drivers
        • 🛠️Minifilter Altitude
        • 🛠️Hypervisor Code Integrity (HVCI) Disallowed Images
        • 🛠️Windows Filtering Platform (WFP)
        • 🛠️Userland Hooking Bypass
      • UAC Bypass
      • AMSI Bypass
      • ETW evasion
      • Living Off The Land
        • Windows Sysinternals
        • LOLBAS Project
        • File Operations
        • File Executions
      • Signature Evasion
      • Obfuscation
        • PowerShell Obfuscation
        • 🛠️Commandline Obfusaction
        • 🛠️PE Obfuscation
        • 🛠️String Encryption
      • AppLocker Bypass
      • Mark-of-the-Web (MotW) Bypass
      • 🛠️PowerShell Constrained Language Mode (CLM) Bypass
      • 🛠️Kill Windows Defender
      • 🛠️Virtualization-based security (VBS) Bypass
        • 🛠️Credential Guard bypass
        • 🛠️hypervisor-protected code integrity (HVCI) Bypass
        • 🛠️Windows Defender Application Control (WDAC) Bypass
      • 🛠️Sandbox Evasion
    • Discovery
      • Active Directory
      • Windows
        • System Information
        • Processes & Services
        • Scheduled Tasks
        • Installed applications
        • Network Configuration
        • FIle/Folder ACLs
        • Knowing your Shell
        • Security Solutions
      • Linux
        • OS Details
        • 🛠️Process & Services
    • Privilege Escalation
      • Windows
        • Tools ⚙️
        • PowerShell Logging
        • Credentials In Files
        • Abusing Tokens
        • Insecure Services
          • Weak Service Permissions
          • Weak File/Folder Permissions
          • Weak Registry Permissions
          • Unquoted Service Path
        • AlwaysInstallElevated
        • AutoLogon Registry
        • Insecure Scheduled Tasks
          • Weak File/Folder Permissions
        • 🛠️DLL Hijacking
      • Linux
        • Kernel Exploits
          • OverlayFs Exploits
            • GameOverlayFs
            • CVE-2023-0386
            • CVE-2021-3493
          • CVE-2023-32233 (CAP_NET_ADMIN)
          • Dirty Pipe
          • 🛠️DirtyCow
          • 🛠️RDS
          • 🛠️Full Nelson
          • 🛠️Mempodipper
        • GLIBC Exploits
          • Looney Tunables
        • Polkit Exploits
          • PwnKit
          • D-Bus Authentication Bypass
        • Sudo Exploits
          • Sudo Binaries
          • Sudo Misconfigurations
          • Reuse Sudo Tokens
          • User Restriction Bypass
          • Pwfeedback BOF
          • Baron Samedit
          • Sudoedit Bypass
        • SUID Binaries
        • Script Exploits
          • Python
            • Pip Download Code Execution
            • PyInstaller Code Execution
            • Pytorch Models/PTH Files Code Execution
          • Ruby
          • Bash
          • Perl
        • Scheduled tasks
          • Cron Jobs
          • Systemd timers
        • Interesting Groups
          • Lxd
        • Capabilities
        • NFS no_root_squash/no_all_squash
        • Linux Active Directory
    • Credential Access
      • Password Stores
        • Windows Credential Manager
        • KeePass
        • Web Browsers
      • Unsecured Credentials
        • Credentials In Files
        • VNC Config
        • SSH Private Keys
        • Git Repositories
        • Veeam Backup
        • Network shares
        • Network protocols
      • OS Credentials
        • Windows & Active Directory
          • SAM & LSA secrets
          • DPAPI secrets
          • NTDS secrets
          • LSASS secrets
          • DCSync
          • Kerberos key list
          • Group Policy Preferences
          • AutoLogon Registry
          • In-memory secrets
          • Cached Kerberos tickets
        • Linux
          • Shadow File
          • In-memory secrets
          • Linux Cached Kerberos tickets
      • MITM and coerced auths
      • Password Attacks
        • Default, weak & Leaked Passwords
        • Generate Wordlists
        • Brute-Force
          • Online - Attacking Services
          • Offline - Password Cracking
      • Impersonation
    • Lateral Movement
      • Port Forwarding
      • TLS Tunneling (Ligolo-ng)
      • HTTP(s) Tunneling
      • SSH Tunneling
      • DNS Tunneling
      • SMB-based
      • WinRM
      • Remote WMI
      • DCOM
      • Scheduled Tasks (ATSVC)
      • Services (SVCCTL)
    • Exfiltration
      • Exfiltration over ICMP
      • Exfiltration Over DNS
      • Exfiltration Over HTTP(s)
      • Exfiltration Over SMB
  • Web Pentesting
    • Reconnaissance
      • Subdomains enumeration
      • WAF Enumeration
    • Infrastructures
      • DBMS
        • Enum Databases
        • Read/Write/Execute
      • DNS
        • Subdomain Takeover
      • Web Servers
        • Nginx
        • Apache
          • Apache Commons Text
          • Apache Tomcat
      • CMS
        • Wordpress
        • 🛠️Joomla
        • 🛠️Drupal
        • 🛠️Bolt CMS
      • Frameworks
        • Spring Framework
          • Spring Routing Abuse
          • Spring Boot Actuators
          • Spring View Manipulation
        • Werkzeug
        • 🛠️Django
        • 🛠️Flask
        • 🛠️Laravel
      • CGI
    • Web Vulnerabilities
      • Server-Side
        • NoSQL Injection
        • SQL Injection
          • UNION Attacks
          • Blind Attacks
            • Boolean Based
            • Time Based
            • Error Based
        • Insecure Deserialization
          • .NET Deserialization
          • Python Deserialization
          • PHP Deserialization
          • 🛠️Java Deserialization
          • 🛠️Ruby Deserialization
        • File Inclusion & Path Traversal
          • LFI to RCE
            • PHP Wrappers
            • Logs Poisoning
            • /proc
            • PHPInfo
            • PHP Sessions
            • Segmentation Fault
          • RFI to RCE
        • Command Injection
        • Brute-Force
        • SSTI (Server-Side Template Injection)
        • Exposed Git Repositories
        • 🛠️File Upload
      • Client-Side
        • XSS (Cross-Site Scripting)
        • CORS (Cross-origin resource sharing)
  • Network Pentesting
    • Network services
      • DNS
      • FastCGI
      • HTTP & HTTPS
      • LDAP
      • NFS
      • MS-RPC
      • MSSQL
      • NBT-NS (NetBIOS)
      • Oracle TNS
      • RDP
      • Rsync
      • SMB
      • SMTP
      • SNMP
      • SSH
      • WebDAV
      • WinRM
      • XMPP/Jabber
      • 🛠️RPC Port Mapper
      • 🛠️FTP
      • 🛠️Telnet
      • 🛠️MySQL
    • WiFi
      • 🛠️WEP
      • 🛠️WPA2
      • 🛠️WPS
    • Bluetooth
  • Active Directory Pentesting
    • Reconnaissance
      • Tools ⚙️
        • PowerView ⚙️
        • Responder ⚙️
        • BloodHound ⚙️
        • enum4linux ⚙️
      • Network
        • DHCP
        • DNS
        • NBT-NS
        • Port scanning
        • SMB
        • LDAP
        • MS-RPC
      • Objects & Settings
        • DACLs
        • Group policies
        • Password policy
        • LAPS
    • Movement
      • Credentials
        • Dumping
        • Cracking
        • Bruteforcing
          • Guessing
          • Spraying
          • Stuffing
        • Shuffling
      • MITM and coerced auths
        • ARP poisoning
        • DNS spoofing
        • DHCP poisoning
        • DHCPv6 spoofing
        • WSUS spoofing
        • LLMNR, NBT-NS, mDNS spoofing
        • ADIDNS poisoning
        • WPAD spoofing
        • MS-EFSR abuse (PetitPotam)
        • MS-RPRN abuse (PrinterBug)
        • MS-FSRVP abuse (ShadowCoerce)
        • MS-DFSNM abuse (DFSCoerce)
        • MS-EVEN abuse (CheeseOunce)
        • PushSubscription abuse
        • WebClient abuse (WebDAV)
        • Living off the land
        • 🛠️NBT Name Overwrite
        • 🛠️ICMP Redirect
      • NTLM
        • Capture
        • Relay
        • Pass the hash
      • Kerberos
        • Pre-auth bruteforce
        • Pass the key
        • Overpass the hash
        • Pass the ticket
        • Pass the cache
        • Forged tickets
          • Silver tickets
          • Golden tickets
          • Diamond tickets
          • Sapphire tickets
          • RODC Golden tickets
          • MS14-068
        • ASREQroast
        • ASREProast
        • Kerberoast
        • Delegations
          • (KUD) Unconstrained
          • (KCD) Constrained
          • (RBCD) Resource-based constrained
          • S4U2self abuse
          • Bronze Bit
        • Shadow Credentials
        • UnPAC the hash
        • Pass the Certificate - PKINIT
        • sAMAccountName spoofing
        • SPN-jacking
      • Netlogon
        • ZeroLogon
      • DACL abuse
        • AddMember
        • ForceChangePassword
        • Targeted Kerberoasting
        • WriteOwner
        • ReadLAPSPassword
        • ReadGMSAPassword
        • Grant ownership
        • Grant rights
        • Logon script
        • Rights on RODC object
      • Group policies
      • Trusts
      • Certificate Services (AD-CS)
        • Certificate templates
        • Certificate authority
        • Access controls
        • Unsigned endpoints
        • Certifried
      • Schannel
        • Pass the Certificate - Schannel
      • SCCM / MECM
        • Privilege Escalation
        • Post Exploitation
      • Exchange services
        • PrivExchange
        • ProxyLogon
        • ProxyShell
        • ProxyNotShell
      • Print Spooler Service
        • PrinterBug
        • PrintNightmare
      • Built-ins & settings
        • Builtin Groups
          • DNSAdmins
          • AD Recycle Bin
        • MachineAccountQuota
        • Pre-Windows 2000 computers
        • RODC
    • Persistence
      • Skeleton key
      • SID History
      • AdminSDHolder
      • GoldenGMSA
      • Kerberos
        • Forged tickets
        • Delegation to KRBTGT
      • Certificate Services (AD-CS)
        • Certificate authority
        • Access controls
        • Golden certificate
      • LAPS
      • 🛠️DC Shadow
      • 🛠️Access controls
  • 🛠️Cloud & CI/CD Pentesting
    • CI/CD
      • Ansible Pentesting
      • Artifactory Pentesting
      • Docker Registry
        • 🛠️HTTP API V2
      • 🛠️Kubernetes
      • 🛠️GitLab
      • 🛠️Github
      • 🛠️Gitea
      • 🛠️Jenkins
      • 🛠️Terraform
    • Azure Pentesting
      • Reconnaissance
        • Tools ⚙️
        • Unauthenticated Reconnaissance
        • Internal Reconnaissance
      • Movement
        • Credentials
          • Password Spraying
          • Token Manipulation
            • Pass-The-Cookie (PTC)
            • Pass the Certificate (Azure)
            • Pass the PRT
        • Aazure Resources
          • Key Vault
          • Storage Accounts
          • Virtual Machines
          • Automation
          • Databases
        • Role-Based Access
        • Conditional Access
        • Service Principals & Applications
        • Hybrid Identity
          • Password Hash Sync (PHS)
          • Pass-through Authentication (PTA)
          • Active Directory Federation Services (ADFS)
          • Seamless SSO
          • Cloud Kerberos Trust
        • Cross-Tenant Access
      • Persistence
    • GCP Pentesting
    • AWS Pentesting
  • 🛠️Smart Contracts Pentesting
    • Solidity
      • Vulnerabilities
        • Delegatecall Attack
        • Denial of Service Attack
        • Overflow & Underflow
        • Reentrancy Attack
        • Self Destruct Attack
        • Tx Origin Attack
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  1. Active Directory Pentesting
  2. Movement
  3. Kerberos

Pre-auth bruteforce

Last updated 2 years ago

Was this helpful?

Theory

The Kerberos authentication protocol works with tickets in order to grant access. A ST (Service Ticket) can be obtained by presenting a TGT (Ticket Granting Ticket). That prior TGT can only be obtained by validating a first step named "pre-authentication" (except if that requirement is explicitly removed for some accounts, making them vulnerable to ASREProast).

The pre-authentication requires the requesting user to supply its secret key (DES, RC4, AES128 or AES256) derived from his password. An attacker knowing that secret key doesn't need knowledge of the actual password to obtain tickets. This is called .

Sometimes, the pre-authentication is disabled on some accounts. The attacker can then obtain information encrypted with the account's key. While the obtained TGT cannot be used since it's encrypted with a key the attacker has no knowledge of, the encrypted information can be used to bruteforce the account's password. This is called ASREProast.

Last but not least, the pre-authentication step can be bruteforced. This type of is way faster and stealthier than other bruteforcing methods relying on NTLM. Pre-authentication bruteforcing can even be faster by using UDP as the transport protocol, hence requiring less frames to be sent.

Practice

Tools like (Go) and (Python) can be used to bruteforce credentials through the Kerberos pre-authentication. The smartbrute utility can be used in a brute mode (standard bruteforcing features) or in a smart mode (requires prior knowledge of a low-priv user credentials, but operates LDAP enumeration and avoid locking out accounts, fetches the users list and so on).

# brute mode, users and passwords lists supplied
smartbrute.py brute -bU $USER_LIST -bP $PASSWORD_LIST kerberos -d $DOMAIN

# smart mode, valid credentials supplied for enumeration
smartbrute.py smart -bP $PASSWORD_LIST ntlm -d $DOMAIN -u $USER -p $PASSWORD kerberos

In its default setup, smartbrute will attack Kerberos pre-authentication with the RC4 etype and the UDP transport protocol. While this configuration is the fastest, there are two downsides:

  • bruteforcing with the RC4 etype is not the stealthiest option

  • using UDP can lead to some support issues. For instance, a valid authentication on a user part of too many groups could raise a KRB_ERR_RESPONSE_TOO_BIG error. When an authentication attempt is invalid, a common KDC_ERR_PREAUTH_FAILED message should be raised. This allows for bruteforcing, but not authentication.

Resources

pass-the-key
credential bruteforcing
kerbrute
smartbrute
LogoGitHub - ropnop/kerbrute: A tool to perform Kerberos pre-auth bruteforcingGitHub