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You can also create a. and L-M passwords using online services.

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We'll review now one of the many services of this type.

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You can enter a cryptographic resource in the form online hash Krekar dot com looking search will display

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the plaintext password used for generating the provided cryptographic resource.

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Let's see what happens if we search for one of the found hashes will choose land manager.

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This brings us back to the previous modules.

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It's not very clever to submit your own passwords to a dubious or untrusted service as you can see the

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hash has been correctly identified as a LAN Manager algorithm.

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It also turns out that the cryptographic resource was extracted from the password.

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He one.

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You can use a variety of methods to crack a password if you have an appropriate cryptographic resource.

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The showcase service also allows users to crack WPA to keys.

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Although this feature has to be paid for in most cases

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if I hash you provide is not found in the correct Tasha's database the site creators can crack it for

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you for a small fee.

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This was the last practical presentation in this module.

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What other ways can be used to obtain a user's identity.

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Replay attacks were extremely popular some time ago and even today they can still compromise Windows

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XP systems with default settings

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the attack exploits a vulnerability found in the land manager and enty land manager protocols.

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The protocols don't sign challenge in response messages and messages are not time stamped.

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This means that a message can be re-used unnoticeably

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SMB and SMB relay or programs shared on the Internet that can help you exploit this hands on an attack

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scenario is as follows.

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A client attempts to connect to a server the client has to be persuaded to connect to us.

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This can be done for example by sharing some interesting resource this attack.

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Just like the ones shown before aims to convince you that local area networks are not more secure than

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the internet.

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Sending your credentials over a local area network can be as dangerous as sending them over the Internet.

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The server should forward a challenge next since we want to connect to it.

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Instead it tells us that it wants to connect to us.

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What a coincidence.

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We react in a correct way

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following the protocol we send the challenge.

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At this point this challenge is a message that we the clients send to a server.

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Next the server realizes that we wanted to connect to it and sends a challenge message

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as it happens.

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The challenge is the same challenge that we sent to it a while before.

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We don't know that though.

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Since we have received a challenge message we encrypt it in an appropriate way using an NC or Allen

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password and for it as a response to our or the server's challenge.

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The server doesn't attempt any cryptanalysis and sends back the same response to our challenge.

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The result of this abuse is that the user pictured above in the slide has been authenticated to the

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computer of the user pictured below on the left and not the other way around.

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What's more the attackers gain the permissions of the user who started the process

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what are the countermeasures signing packets is a good solution.

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Since Allemagne and TLM don't implement this feature you need to sign packets and then they'll Aprilaire

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SMB protocol packets should be signed.

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The slide above shows how to enable SNB packet signing

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challenge response attacks have also been shown cracking the passwords was easy and fast.

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Windows has a setting that specifies which version of an authentication protocol issued by a specific

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provider will be used.

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Take a look at the options you can select sending Elham or TLM responses.

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Nothing less secure is available.

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You can also send L-M an anti alarm and if negotiated use and TLM version to if an attacker doesn't

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agree to it will send only L-M and TLM.

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The solution is just as vulnerable.

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You can also send only TLM responses without L-M this doesn't tighten security in practice however.

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The minimum authentication security level that should be set for all client computers is sending and

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TLM version 2 responses.

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If Kerberos responses fail you should only use anti-oil and version to server properties on the other

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hand should be configured to the last security level only and TLM version 2 responses should be sent

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L-M or TLM should be refused.

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If this policy is set on a server and a client has set the policy we talked about before the security

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is as high as possible without Kerberos

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Kerberos doesn't offer full protection either.

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There's no such thing as a protection guarantee with security

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Kerberos is susceptible to a certain class of attacks to attacks that compromised long term keys

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to run them.

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An attacker needs to get a hold of some cryptographic resources.

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This can be done by capturing the communications between a client that requests the TGT key and a domain

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controller.

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What happens then.

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We know already that the user's identity is verified against the message sent to and decrypted by a

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domain controller that contains a time stamp.

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The tolerance window for differences between the time stamp and the controller system time is 5 minutes.

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The problem is the time stamps always have the same structure.

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You know what the front or day month year and then hour minute second busy at the end.

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Z stands for Zulu.

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If we sniff out or obtain some encrypted resource and while trying to decrypt it using potential passwords

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we need the user passwords list again will get a value that looks like a time stamp.

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This means that the password is cracked.

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There's little chance that we'd get that time stamp value using a different key.

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This is how curb sniff works Kirsan if it's a light 10 year old application you can find on the internet

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it should be launched at the communications line between the client and I don't mean controller this

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line is relatively safe.

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Most administrators take steps to protect as you can see this protection has good grounds

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this module featured facts knowledge on varied methods of identity theft Windows system user credentials

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were used as an example.

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We showed off line attacks and outlined replay attacks online attacks.

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The module also showed the techniques and tools needed to capture a user's password.

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In about five minutes or less.

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Thank you.