Questions tagged [kerberos]

Kerberos is a network authentication protocol designed to allow nodes, communicating over a non-secure network, to prove their identity to one another in a secure manner.

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Kerberos: How could an attacker exploit insider access to invalidate tickets for a service?

Assume: the attacker has legitimate insider access to a Kerberos system. Background: The attacker is looking to invalidate all tickets for a service (maybe he really dislikes a service). To do so, ...
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Why first kerberos message is not ciphered

When analysing Kerberos exchange (and other similars as Needham, Denning, etc.) I wonder why the first message where the identities of the client and remote are not encrypted. In case not encrypted I ...
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With a 'man in the middle' attack, can the attacker find out Client/Server session keys with a compromised AS/TGS secret key?

Assuming that an AS/TGS secret key has been compromised by a 'man in the middle' attack who in turn can monitor the network traffic, is an attacker able to find out the Client/Server session keys ...
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Kerberos Encryption and Decryption

Hacker is able to sniff the traffic between the editor, the KDC and the network scanner during the key exchange. Is he/she able to decrypt the sniffed data key?
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Kerberos Authentication : Client authentication only

I am currently implementing a way to authenticate using Kerberos mechanism. Then only explanation have is "SSO using Kerberos". I know technically how works Kerberos (Keytab, SPNEGO, Token, KDC, SPN)...
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In Kerberos authentication protocol, why is the TGT encrypted using the user's key Ka?

When the user first logs in, he fetches his TGT from the KDC along with the session key. I get why Sa (session key) is encrypted with Ka (user's key). But why is TGT also encrypted with Ka. TGT is ...
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How to retrieve Kerberos Service tickets?

I am learning Kerberoasting see below are my steps that I am following. Step:1. Attacker will find the SPN's Step:2. After identifying we will request for TGS for that SPN. This is the script for ...
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What is possible with a non-administrative users Ticket Granting Ticket and/or NTLM hash?

During a penetration test, if a users NTLM hash or a valid Kerberos TGT is compromised, what attacks are possible if the user is not an administrator on any (in scope) workstations? For instance, it ...
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Why Realm_tgs is needed in Kerberos v5 Protocol? (Step 2)

In msg.2 the AS sends Realm_c, ID_c Ticket_tgs, K_c-tgs, times, N1, Real_tgs, ID_tgs encrypted with E_k_c. I can't understand why Real_tgs is included if AS and TGS are on the same machine.
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How to crack AES-based Kerberos TGS tickets (Kerberoasting)?

All material I can find is related to RC4-based Kerberos TGS tickets, since these are easier to crack to obtain the service account's password. However, I want to attempt to crack AES-based Kerberos ...
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744 views

A replay attack was detected (4649) & Exchange Healthmailbox

We received alarms for this in our SIEM today. I believe it is expected and just "noise". The alarm was triggered immediately after Exchange cleared the ThrottlingConfig.log. I know Exchange Server ...
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Mimikatz /rc4 argument for pass-the-ticket?

I'm studying how pass-the-ticket works using Mimikatz, i.e., forged Silver and Golden Kerberos tickets. The command usually takes the form (Golden tickets): kerberos::golden /sid:SID /domain:DOMAIN /...
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Is principal type supported in Linux Kerberos utilities?

In the Windows ktpass command, the –ptype option can be used to specify a principal type. Is there a similar option in ktutil, kinit or any of the Linux Kerberos utilities?
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574 views

Password reset for AD RODC-specific krbtgt_xxxxx accounts

While there's a lot of information [1], [2], [3] about resetting the password for the regular krbtgt account, but I haven't yet found a clear suggestion about RODC-specific krbtgt_xxxxx accounts. ...
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Principal Password in Kerberos KDC database

Is there a way for me to merge a bank account number, fingerprint image and IMEI of a phone into a single entity that I could possibly use as a password in the Kerberos KDC to uniquely identity a ...
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What are the flaws in this security protocol between client and server? [closed]

Here is my security protocol for the use of a service provided by server. It utilises a symmetric key: Client requests to use a service Server sends back nonce Client sends back nonce encrypted with ...