harmj0y kerberoastingharmj0y kerberoasting

harmj0y kerberoasting28 May harmj0y kerberoasting

So whats the disadvantage here? And the best part is that everything needed is already implemented in PowerView with Set-DomainObject and Get-DomainSPNTicket! This is the key to Kerberoasting. which finally clarified a few points involved in this process that were fuzzy to me. What is Kerberoasting? So basically, its outputting objects with incorrect data when it should output nothing for that identity because there was an error. HarmJ0y has written a good blog on kerberoasting without Mimikatz. If the SPN is MSSQLSvc/adsmsDB01.adsecurity.org:1433, then MSSQLSvc is the SPN type. For conciseness Im going to refer to these as, A standalone implementation of the Kerberos protocol thats used through a device connected on a network, or via piping the crafted traffic in through a SOCKS proxy. Kerbrute is a popular enumeration tool used to brute-force and enumerate valid active-directory users by abusing the Kerberos pre-authentication. Kerberoasting - HackBook The kerberoast /rc4opsec command executes the tgtdeleg trick and filters out any of these AES-enabled accounts: If we want the opposite and only want AES enabled accounts, the /aes flag will do the opposite LDAP filter. Can the hash output from the command of Invoke-Kerberaost be used to create a silver ticket using Mimikatz ? Kerberoasting Background I first heard about Kerberoasting from Tim at SANS HackFest 2014 during his "Attacking Kerberos: Kicking the Guard Dog of Hades" talk (he also released a Kerberoasting toolkit here). These events can be filtered using the following which greatly reduces the amount of events flowing into the SIEM/Splunk: With this information, we can start investigating potential Kerberoasting activity and reduce the number of 4769 events. However, we. Tim Medin presented on this at DerbyCon 2014 in his Attacking Microsoft Kerberos Kicking the Guard Dog of Hades presentation (slides & video) where he released the Kerberoast Python TGS cracker. Get-NetUser -AdminCount | Select name,whencreated,pwdlastset,lastlogon. ): after a user authenticates to the key distribution center (KDC, which in the case of a Windows domain is the domain controller) they receive a ticket-granting-ticket (TGT) signed with the domain krbtgt account that provesthey are who they say they are. Another advantage of this approach is that the existing users TGT is used to request the service tickets, meaning we dont need plaintext credentials or a users hash to perform the Kerberoasting. We often times operate over high-latency command and control, so for complex multi-party exchanges like Kerberos our personal preference has traditionally been the KerberosRequestorSecurityToken approach for Kerberoasting. Kerberoasting: Requesting RC4 Encrypted TGS when AES is Enabled . Filter out requests from service accounts (ads45service@lab.adsecurity.org). Configuring Logging to Detect Kerberoast Activity. Any user authenticated to Active Directory can query for user accounts with a Service Principal Name (SPN). If you have elevated (i.e. Sean Metcalf has an excellent post titled Detecting Kerberoasting Activity that covers how to approach DC events to detect this type of behavior, though as he notes false positives are likely.. . ticket being added to the current logon session, minimizing a potential host-based indicator (i.e. A Wireshark capture confirms that RC4 is the only supported etype in the request, and that the ticket enc-part is indeed encrypted with RC4. This involves creating a domain user and then mapping a SPN to that account. Password converted to NTLM hash, a timestamp is encrypted with the hash and sent to the KDC as an authenticator in the authentication ticket (TGT) request (AS-REQ). Note: By brute-forcing Kerberos pre-authentication, you do not trigger the account

failed to log on event which can throw up red flags

to the

blue team

. Kerberoast can attempt to open the Kerberos ticket by trying different NTLM hashes and when the ticket is successfully opened, the correct service account password is discovered. Using the Active Directory powershell module, we can use the Get-ADUser cmdlet: Since Kerberoasting is such a commonly used technique, I wanted to dive into detail now that we have a better understanding of its nuances. This attack is effective since people tend to create poor passwords. . Note that the initial krbtgt ticket is AES encrypted and others are RC4-HMAC(NT). Kerberoasting your way in. Introduction | by mohit panwar | Medium Kerberoast. The next graphic shows the results of the PowerShell script code being run. If this property is not defined, or is set to 0,[MS-KILE] 3.3.5.7 tells us the default behavior is to use a value of 0x7, meaning RC4 will be used to encrypt the service ticket. TryHackMe - Attacking Kerberos | amirr0r Just some of the many tools and attacks include overpass . The ticket options may be different, so just filter on 4768 & 4769 events with Ticket Encryption: 0x1 OR 0x2 OR 0x3. Kerberoasting Without Mimikatz - harmj0y While we dont currently have tools to crack tickets that use AES (and even once we do, speeds will be thousands of times slower due to the AES key derivation algorithms), approach for Kerberoasting is that since were building and parsing the TGS-REQ/TGS-REP traffic manually, the service tickets wont be cache on the system were roasting from. However, remember that arbitrary SPNs can also be registered for domain, accounts as well. Penetration Testing Lab. is set to 24, specifying only AES 128/256 encryption should be supported. Furthermore, most service accounts are over-permissioned and are often members of Domain Admins providing full admin rights to Active Directory (even when the service account only needs to modify an attribute on certain object types or admin rights on specific servers). The most effective mitigation of this attack is ensuring service account passwords are longer than 25 characters (and arent easily guessable) Could you give me a hint how you were able to utilize hashcat for the cracking stage? A quick way to check for this is to enumerate all user accounts with the attribute AdminCount equal to 1. This approach is still dependent on the target user having a weak/crackable password, but its a nice alternative to force-resetting the users password. As modern domains (functional level 2008 and above) and computers (Vista/2008+) support using AES keys by default in Kerberos exchanges, the use of RC4 in any Kerberos ticket-granting-ticket (TGT) requests or service ticket requests, that covers how to approach DC events to detect this type of behavior, though as he notes , To illustrate, lets say we have a user account, registered in its servicePrincipalName (SPN) property. The /spn:X argument roasts just the specified SPN, the /user:X argument roasts just the specified user, and the /ou:X argument roasts just users in the specific OU. The enc-part in the returned TGS-REP (service ticket reply) is properly encrypted with the requesting clients AES256 key as we would expect. Warning: A skeleton key only works using Kerberos RC4 encryption. For more information on Rubeus, check out the "From Kekeo to Rubeus" release post, the follow up "Rubeus - Now With More Kekeo", or the recently revamped . However, the resulting service ticket applied to the current logon session specifies RC4, despite the requesting users (harmj0y) TGT using AES256. There have also been times in the field where the default KerberosRequestorSecurityToken Kerberoasting method has just failed- were hoping that the. We are currently in the process of refactoring large components of PowerSploit, and the updated functions will be posted here after the changes are published. Recently I have had a lot of success with privilege escalation in an Active Directory domain environment using an attack called Kerberoasting. FIMService: Often has admin rights to multiple AD forests. Kerberos credential, see inner exception for details. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. atomic-red-team/T1558.003.md at master - GitHub AS-REP Roasting dumps the krbasrep5 hashes of user accounts that have Kerberos pre-authentication disabled. Given GenericWrite/GenericAll DACL rights over a target, we can modify, save for attributes related to delegation, and other protected components like sidHistory. In password spraying, you take a given Kerberos-based password (such as P@$$W0rd) and spray against all found user accounts in the domain to find which one may have that password. the crackable hash component) of the TGS. The Kerberos backdoor works by **implanting a skeleton key** that abuses the way that the AS-REQ validates encrypted timestamps. The general concept of Kerberoasting is requesting service tickets (TGS) from the KDC (Kerberos Domain Controller) that are associated with service accounts to retrieve their hashes. Impacket v0.9.22 - Copyright 2020 SecureAuth Corporation This is why inter-domain trust tickets end up using RC4 by default: However, like with user objects, this behavior can be changed by modifying the properties of the trusted domain object, specifying that the foreign domain supports AES: This sets msDS-SupportedEncryptionTypes on the trusted domain object to a value of 24 (AES128_CTS_HMAC_SHA1_96 | AES256_CTS_HMAC_SHA1_96), meaning that AES256 inter-domain trust tickets will be issued by default: Due to the way we tend to execute engagements, we often lean towards abusing host-based functionality versus piping in our own protocol implementation from an attacker server. The ticket is sent back to the attacker in a service ticket reply (TGS-REP). However, remember that arbitrary SPNs can also be registered for domain user accounts as well. @harmj0y covered the technical details here, but at a high level, S4U2Self allows an account to request a service ticket to itself on behalf . When a domain user requests access to \\WINDOWS1.testlab.local\C$, the KDC maps this request to the HOST/WINDOWS1.testlab.local SPN, indicating that the WINDOWS1$ machine account NTLM hash (which is stored both on WINDOWS1 locally and the NTDS.dit Active Directory database on the DC/KDC) should be used to encrypt the server part of the service ticket. Learn how your comment data is processed. When brute-forcing through Kerberos you can brute-force by only sending a single UDP frame to the KDC allowing you to enumerate the users on the domain from a wordlist. Only the first of the 13 is correct. cifs/DC.domain.com). While we dont currently have tools to crack tickets that use AES (and even once we do, speeds will be thousands of times slower due to the AES key derivation algorithms), progress is being made. Note that the -AdminCount flag only Kerberoasts accounts with AdminCount=1, meaning user accounts that are (or were) protected and, therefore, almost always highly privileged: And heres how the updated Empire module looks: Note that for non-Empire weaponizations, as PSObjects are output, you will need to pipe the results to Format-List or ConvertTo-Csv -NoTypeInformation in order to preserve the information you want displayed. We can further reduce the number of 4769 events that flow into SIEM/Splunk: In limited testing, Ive seen 4769 event totals reduced from millions to thousands and hundreds using these filtering techniques. Mimikatz is very popular for dumping user credentials inside an active directory environment, however it can also be used to dump a TGT from LSASS memory. This attack is effective since people tend to create poor passwords. password is used for the service ticket creation. 3. Logging 4769 events on Domain Controllers, filtering these events by ticket encryption type (0x17), known service accounts (Account Name field) & computers (Service Name field) greatly reduces the number of events forwarded to the central logging and alerting system. Not directly, no. Seems like maybe youre reusing some variables from identity to identity where if an operation on an identity fails the script still outputs an object but it just contains the SPN/Hash of the last identity that succeeded. Any Kerberos RC4 tickets requested should be the exception. Kerberoasting is a technique often used in domain penetration. Kerberoast. Blog - harmj0y A third party product that provides password vaulting is also a solid solution for managing service account passwords. Great work. Save my name, email, and website in this browser for the next time I comment. Pingback: HackTheBox Active Write-Up Hacking Anarchy, Pingback: Threat Hunting for Dridex Attacks: Red Canary & Carbon Black, Pingback: Threat Hunting for Dridex Attacks: Top Questions from Security Teams | Carbon Black, Pingback: How to: Kerberoast like a boss Cyber Security Pad Cyber Security | Home Automation | Risk Management, Your email address will not be published. in this instance. After a bit of testing, it appears that if you disable RC4 at the domain/domain controller level, then requesting a RC4 service ticket for any account will fail with KDC_ERR_ETYPE_NOTSUPP. Dumping the hash and SID of the krbtgt service account, The share will now be accessible without the need for the Administrators password, Access the directory of Desktop-1 without ever knowing what users have access to Desktop-1. Given modification rights on a target, we can change the users serviceprincipalname to any SPN we want (even something fake), Kerberoast the service ticket, and then repair the serviceprincipalname value. Is there a way to enumerate service accounts viable for those 100 hosts, only, or do I have to always enumerate all service accounts over the entire (humongous) domain? This approach allows us to extract a usable TGT for the current user, including the session key. A single user requesting RC4 encrypted TGS tickets for several services, such as lots of SQL service principal names is suspicious and its worth investigating the IP (client address) the requests came from. Im assuming that this is for failsafe backwards compatibility reasons, and I ran this scenario in multiple test domains with the same result. This approach is in fact now implemented in Rubeus with the /ticket: parameter for the kerberoast command. When I first was looking at this, I assumed that this meant that since the msDS-SupportedEncryptionTypes value was non-null, and the RC4 bit was NOT present, that if you specify only RC4 when requesting a service ticket (via the /tgtdeleg flag here) for an account configured this way the exchange would error out. Running klist shows the new Kerberos service ticket with RC4-HMAC encryption. To reiterate, any domain user account that has a service principal name set can have a TGS for that SPN requested by any user in the domain, allowing for the offline cracking of the service account plaintext password! Note: The skeleton key will not persist by itself because it runs in the memory, it can be scripted or persisted using other tools and techniques. I have added the module to empire and tested it against my lab domain. Strong password policy. When brute-forcing passwords you use a single user account and a wordlist of passwords to see which password works for that given user account. Expect there will be around 10 to 20 Kerberos TGS requests per user every day. We can request a service ticket for this SPN with. Messing with Kerberos using Rubeus - Red Team Techniques - GitHub Pages Rubeus (developed by HarmJ0y) is an adaptation of the kekeo toolset. comparing the different Rubeus Kerberoasting approaches: As a final note, Kerberoasting should work much better over domain trusts, . Weve been brainstorming another method to abuse these types of relationships with the target remaining unaware, and we believe we now have another option. Domain Controllers can log Kerberos TGS service ticket requests by configuring Audit Kerberos Service Ticket Operations under Account Logon to log successful Kerberos TGS ticket requests. There are two types of service principal names in Active Directory: host-based SPNs that are linked to a domain computer account and arbitrary SPNs that are usually (but not always) linked to a domain user account. As Kerberos is an authentication protocol it is possible to perform brute-force attacks against it (providing we are careful). You can then crack these tickets as, Again, the self-contained, PowerShell 2.0-compliant script is on my. A few recent(ish) things really simplified our usage of Kerberoasting on engagements. This attack is effective since people tend to create poor passwords. Dump the Kerberos hash of any kerberoastable users: Dont let your domain admins log onto anything except the domain controller - This is something so simple however a lot of domain admins still log onto low-level computers leaving tickets around that we can use to attack and move laterally with. Using built-in Windows functionality on a domain-joined host (like the, class) to request tickets which are then extracted from the current logon session with. get-aduser -filter {AdminCount -eq 1} -prop * | select name,created,passwordlastset,lastlogondate, We can also use PowerViews Get-NetUser cmdlet: Kerberoasting Revisited - harmj0y This is obviously dependent on a crackable service account plaintext, but luckily for us service accounts tend to often have simple passwords that change very infrequently. Required fields are marked *. that represents a bitfield with the following possible values: The Key Distribution Center (KDC) uses this information [msDS-SupportedEncryptionTypes] while generating a service ticket for this account. @machosec realized that .NET class KerberosRequestorSecurityToken used in previous approaches also had a GetRequest()method, which returns the raw byte stream of the Kerberos service ticket. https://github.com/PowerShellMafia/PowerSploit/blob/7c32bf69f334b7c15c644cdb41188bdfe1a0b0e8/Recon/PowerView.ps1#L4412-L4414, Detecting Kerberoasting Activity Active Directory Security, Detecting Kerberoasting Activity Part 2 Creating a Kerberoast Service Account Honeypot Active Directory Security, Trimarc Research: Detecting Kerberoasting Activity TRIMARC, Cracking Kerberos TGS Tickets Using Kerberoast Exploiting Kerberos to Compromise the Active Directory Domain Active Directory Security, A Toast to Kerberoast - Black Hills Information Security, HackTheBox Active Write-Up Hacking Anarchy, Threat Hunting for Dridex Attacks: Red Canary & Carbon Black, Threat Hunting for Dridex Attacks: Top Questions from Security Teams | Carbon Black, How to: Kerberoast like a boss Cyber Security Pad Cyber Security | Home Automation | Risk Management, A Case Study in Wagging the Dog: Computer Takeover, Not A Security Boundary: Breaking Forest Trusts. The output of SharpRoast gives you the SamAccountName, DistinguishedName, ServicePrincipalName and the. We can request RC4 encrypted Kerberos TGS service tickets by using the following PowerShell command: $SPNName = MSSQLSvc/adsmsDB01.adsecurity.org:1433 However, TGT requests will no longer work with RC4 either. In the example below, we use the previously retrieved Kerberos ticket to connect to DC01 using Impacket 's smbclient.py script. Rubeus has a wide variety of attacks and features that allow it to be a very versatile tool for attacking Kerberos. I first heard about Kerberoasting from Tim at SANS HackFest 2014 during his Attacking Kerberos: Kicking the Guard Dog of Hades talk (he also released a Kerberoasting toolkit here).

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