You can also create a. and L-M passwords using online services.
We'll review now one of the many services of this type.
You can enter a cryptographic resource in the form online hash Krekar dot com looking search will display
the plaintext password used for generating the provided cryptographic resource.
Let's see what happens if we search for one of the found hashes will choose land manager.
This brings us back to the previous modules.
It's not very clever to submit your own passwords to a dubious or untrusted service as you can see the
hash has been correctly identified as a LAN Manager algorithm.
It also turns out that the cryptographic resource was extracted from the password.
He one.
You can use a variety of methods to crack a password if you have an appropriate cryptographic resource.
The showcase service also allows users to crack WPA to keys.
Although this feature has to be paid for in most cases
if I hash you provide is not found in the correct Tasha's database the site creators can crack it for
you for a small fee.
This was the last practical presentation in this module.
What other ways can be used to obtain a user's identity.
Replay attacks were extremely popular some time ago and even today they can still compromise Windows
XP systems with default settings
the attack exploits a vulnerability found in the land manager and enty land manager protocols.
The protocols don't sign challenge in response messages and messages are not time stamped.
This means that a message can be re-used unnoticeably
SMB and SMB relay or programs shared on the Internet that can help you exploit this hands on an attack
scenario is as follows.
A client attempts to connect to a server the client has to be persuaded to connect to us.
This can be done for example by sharing some interesting resource this attack.
Just like the ones shown before aims to convince you that local area networks are not more secure than
the internet.
Sending your credentials over a local area network can be as dangerous as sending them over the Internet.
The server should forward a challenge next since we want to connect to it.
Instead it tells us that it wants to connect to us.
What a coincidence.
We react in a correct way
following the protocol we send the challenge.
At this point this challenge is a message that we the clients send to a server.
Next the server realizes that we wanted to connect to it and sends a challenge message
as it happens.
The challenge is the same challenge that we sent to it a while before.
We don't know that though.
Since we have received a challenge message we encrypt it in an appropriate way using an NC or Allen
password and for it as a response to our or the server's challenge.
The server doesn't attempt any cryptanalysis and sends back the same response to our challenge.
The result of this abuse is that the user pictured above in the slide has been authenticated to the
computer of the user pictured below on the left and not the other way around.
What's more the attackers gain the permissions of the user who started the process
what are the countermeasures signing packets is a good solution.
Since Allemagne and TLM don't implement this feature you need to sign packets and then they'll Aprilaire
SMB protocol packets should be signed.
The slide above shows how to enable SNB packet signing
challenge response attacks have also been shown cracking the passwords was easy and fast.
Windows has a setting that specifies which version of an authentication protocol issued by a specific
provider will be used.
Take a look at the options you can select sending Elham or TLM responses.
Nothing less secure is available.
You can also send L-M an anti alarm and if negotiated use and TLM version to if an attacker doesn't
agree to it will send only L-M and TLM.
The solution is just as vulnerable.
You can also send only TLM responses without L-M this doesn't tighten security in practice however.
The minimum authentication security level that should be set for all client computers is sending and
TLM version 2 responses.
If Kerberos responses fail you should only use anti-oil and version to server properties on the other
hand should be configured to the last security level only and TLM version 2 responses should be sent
L-M or TLM should be refused.
If this policy is set on a server and a client has set the policy we talked about before the security
is as high as possible without Kerberos
Kerberos doesn't offer full protection either.
There's no such thing as a protection guarantee with security
Kerberos is susceptible to a certain class of attacks to attacks that compromised long term keys
to run them.
An attacker needs to get a hold of some cryptographic resources.
This can be done by capturing the communications between a client that requests the TGT key and a domain
controller.
What happens then.
We know already that the user's identity is verified against the message sent to and decrypted by a
domain controller that contains a time stamp.
The tolerance window for differences between the time stamp and the controller system time is 5 minutes.
The problem is the time stamps always have the same structure.
You know what the front or day month year and then hour minute second busy at the end.
Z stands for Zulu.
If we sniff out or obtain some encrypted resource and while trying to decrypt it using potential passwords
we need the user passwords list again will get a value that looks like a time stamp.
This means that the password is cracked.
There's little chance that we'd get that time stamp value using a different key.
This is how curb sniff works Kirsan if it's a light 10 year old application you can find on the internet
it should be launched at the communications line between the client and I don't mean controller this
line is relatively safe.
Most administrators take steps to protect as you can see this protection has good grounds
this module featured facts knowledge on varied methods of identity theft Windows system user credentials
were used as an example.
We showed off line attacks and outlined replay attacks online attacks.
The module also showed the techniques and tools needed to capture a user's password.
In about five minutes or less.
Thank you.