1

Kerberos/Samba/AD account lockouts

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I kept getting the following errors on my AD domain in the event viewer and accounts kept locking out:
Pre-authentication failed:
User Name:      user1
User ID:                DOMAIN\user1
Service Name:   krbtgt/DOMAIN.COM
Pre-Authentication Type:        0x0
Failure Code:   0x12
Client Address: 192.168.246.134

For more information, see Help and Support Center at
http://go.microsoft.com/fwlink/events.asp.

In the Directory Service logs I see the following entry:
[snip]
Active Directory could not update the following object with changes
received from the domain controller at the following network address
because Active Directory was busy processing information.

Object:
CN=User 1,OU=Testing Services Team,OU=TESTER V,DC=domain,DC=com
Network address:
e5523049-53f1-4274-858b-

c68971599acf._msdcs.domain.com

This operation will be tried again later.

For more information, see Help and Support Center at
http://go.microsoft.com/fwlink/events.asp.

Turns out this happens if you have samba/winbind/AD type infrastructure. If someone has some processes running (Even if they us sudo) and happen to change their password while the process is running on unix (and using kerberos authentication), the accounts lockout because the kerberos ticket granting ticket (krbtgt) is not current and any object access is considered to be a failed login attempt. This locks out the accounts if you have account lockout implemented in your AD domain security policy.

1

Brand New Day

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It’s a brand new day with no novelty! Back to the lab today trying to now get access to the packet data to calculate the hash values. I suspect that inside netfilter’s sk_buff structure there’s an unsigned char* data field. This probably is exactly what I need to get the hash values. There’s this awesome link which has great information about sk_buff structure. The unsigned int len; has the size of the complete input data including the headers. I guess if this len value == size of the actual data for the IP header (which could be TCP header / UDP header / ICMP header) then if we are using chunks of this data to find hashes then the following algorithm could be used:

no_of_chunks = len / BYTE_SIZE_FOR_SIGN;

addendum = len % BYTE_SIZE_FOR_SIGN;


for (int i = 0; i < no_of_chunks; i++)
{
storeInTable(hashRabin(data,i*BYTE_SIZE_FOR_SIGN,
(i+1)*BYTE_SIZE_FOR_SIGN - 1 ,0));
}
storeInTable(
hashRabin(data,no_of_chunks*BYTE_SIZE_FOR_SIGN,
no_of_chunks*BYTE_SIZE_FOR_SIGN+addendum, 0)
);


This are my initial thoughts let’s see how it works out!

-Rajat.
Rajat’s Homepage

0

Pass the hash

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In a pen test, it’s always the race to the finish. Either you get to the domain admin or r00t or you die tryin’! 🙂 But thanks to some real l33t fu by Hernan Ochoa this has only been made easy for you.
The key to pass-the-hash attacks is that Windows NTLM authentication relies on the passing of the right hash to identify you. As long as the right hash is stored in the authenticated session you are who you say you are.
Hernan Ochoa’s Pass-the-hash toolkit (http://oss.coresecurity.com/projects/pshtoolkit.htm) is precisely the tool for that. Once you gain local admin rights on a box, just run the whosthere.exe utility on the box. Mind you, in differing versions of Windows you need some right addresses to pass as parameters. So the first thing to do is goto C:\WINDOWS\system32 and copy the lsasrv.dll file onto your local machine. The pass-the-hash src tar ball, has an IDA Pro script passthehash.idc that you need to run after opening the file in IDA Pro. This will give you the right addresses to pass to whosthere.exe:
whosthere.exe -a -o outputfile.txt

Once you have the hash you could either use iam.exe or winexe (http://eol.ovh.org/winexe/) with pass-the-hash patch from jo-mo-kun (http://www.foofus.net/jmk/tools/winexe), or samba with jomo kun’s pass the hash patch.
Just set the Environment variable SMBHASH to the hash value such as

export SMBHASH="92D887C9910492C3254E2DF489A880E4:7A2EDE4F51B94203984C6BA21239CF63"

Then run winexe as

./winexe -U "Domain\\Username" //192.168.0.1 "cmd.exe"

Of course, you can also expend some time in cracking the LM hashes to get the actual passwords but it isn’t really necessary.

0

Installing mplayerplug-in for Firefox-1.0.4

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I love the site www.big-boys.com but in linux it would not play so I wanted to install a browser plugin that would play wmv files.
Here’s how I went about it. First I installed mplayer using yum (I use FC4 with kernel 2.6.13.2).
yum install mplayer
Make sure the internet connection is present when you run this command.

Then I went to Linux Plugins site to get the mplayerplugin. It redirected me to Mplayer Sourceforge site.

Then I downloaded the source of mplayerplug-in from Sourceforge download page for Mplayerplug-in.
Once I did that then came the main struggle of compiling and getting this to run.

I first untarred the file with command:

tar zxvf mplayerplug-in-3.11.tar.gz
cd mplayerplug-in
./configure –with-gecko-sdk=/usr/include/mozilla-1.7.8/
make

But this resulted in a bunch of errors.
I realized that an extra slash was put in there so I opened the Makefile with vim and removed the extra slash at the end of the string /usr/include/mozilla-1.7.8/ in the Makefile.
Tried to make again but again errors this time around some include files called prtypes.h was missing.

I noticed that in the CFLAGS section of the Makefile there was a space between -I and /usr/include. Deleted those.

So opened the Makefile in vim again and added the string -I/usr/include/mozilla-1.7.8/nspr/ to the CFLAGS section of the Makefile.

Also added -L/usr/lib/firefox-1.0.4/ to the LFLAGS section coz I was getting some linker errors after that. The struggle was not over.

I got a linker error :

/usr/bin/ld: cannot find -lxpcomglue
collect2: ld returned 1 exit status

Changed the -lxpcomglue in Makefile to -lxpcom.
Finally, the compilation and the build were successful. Then the final command
cp mplayerplug-in*.so /usr/lib/firefox-1.0.4/plugins/
And now I have mplayerplug-in live and kicking!

-Rajat.

0

OpenSSL-fu

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If you want to find out the components of a site’s certificate the following commands will help you.
If you want to find if the certificate is signed with the weak MD5 signature algorithm:
$ echo | openssl s_client -connect webserver.example.com:443 2>/dev/null | sed -ne ‘/—–BEGIN CERTIFICATE—–/,/—–END CERTIFICATE—–/p’ | openssl x509 -text | grep “Signature Algorithm”| gawk ‘{print $3}’

$ echo | openssl s_client -connect 167.155.38.24:443 2>/dev/null | sed -ne ‘/—–BEGIN CERTIFICATE—–/,/—–END CERTIFICATE—–/p’ | openssl x509 -text | grep “Exponent”

3

West Coast to East Coast: antithetical US

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A moratorium for 3 months on the blogspot. The things have changed dramatically when it comes to the life. A lot has happened in my life since the time I left Los Angeles, CA to come to New York, NY. The two of the biggest cities of not only the USA but in the world as well.
First things first…got a job for Ernst & Young’s Advanced Security Center and so like most of the people who work in New York I live in Jersey City, NJ and travel to work. The travel is not too bad as it takes about 45 mins door-to-door. Also, by living in New Jersey instead of 5 boroughs (New Yorkers call the collection of 5 islands of Manhattan, Queens, Brooklyn, Bronx, Statten Island as the 5 boroughs) one saves the 4% annual New York city tax.
Now for the topic of this blog which is “Moving”…which is probably the most troublesome experience that people have. It wasn’t too good for me either but it could have been worse if it were not for the help of some good friends. People say that you realize the truthfulness of your friends during the time of adversity. It was exactly what I found. Whereas some people came to the fore to help me in all the ways they could, some stayed at the bay (and in some cases … making sure that the buoy of my life was in doldrums). Well…having said that life is but a bunch of grapes … some sweet and some sour (this is something I heard in the Hindi Movie “Khatta Meetha”)!
Finding apartments in the New York area can be a harrowing experience, especially if you are hard strung on budget. That was exactly what I found. The best places to look for are New Jersey Craigslist and New York Craigslist. Other places are Rent.com and Apartments.com but I did not find them much useful. I found that New York had some really good places to rent even with a tight budget. All these places were in Queens (Rego Park, Forest Hills). The good part was one could get a 2BR for $1450+ in these places. These places were not too far from the Subway stations and had a travel of 40-45 mins to Manhattan and 1 hr to Long Island (using Long Island Rail Road aka LIRR).
Jersey City in NJ is also a very good bet. But there are some places in Jersey City that are posh as hell but you have to pay the price for the class. Exchange place and Pavonia/Newport are examples of these places (with prices around $1700 for 1 BR) . Grove street is also a place which is somewhere in between the posh and the not-at-all posh. Even though the prices in Exchange place and Newport are really high but the class is well worth the money. Especially when you consider that getting a similar type of apartment in Manhattan will cost at least twice or may be thrice as much. Another avenue for exploration is Hoboken, NJ. Hoboken was personally my favorite place to look for an apartment because it is a place with a vibrancy associated with it. Almost looks like a European city bustling with restaurants and youth on the streets! It is also not too far from New York. However just like Pavonia/Newport & Exchange Place this fun doesn’t come cheap! The apartment costs are similar. The difference between Newport – Exchange Place & Hoboken is that the construction in Hoboken is older and you need a realtor for getting an apartment more than you need in former. Realtors have standard 1 month rent as the fee as their service charges.
In case you are wondering what a realtor is – a realtor is a person who searches for an apartment for you that fits within your budget and choice. But when it comes to realtors one must be wary of them because they can sometimes be a dangerous bet to pick!
West coast was much easier to find apartments in from my experience but it could be because I was looking for apartments in a University area which is probably easier.

-Rajat
http://rajatswarup.blogspot.com/

2

Bit of Forensics

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I like using dcfldd for creating the raw images, because it shows a nice status…it’s interesting to see progress.

dcfldd if=/dev/sda of=/mnt/sdb1/filename.dd hash=md5 md5log=hashfile.md5 conv=noerror,sync bs=4096

It’s the ‘bs’ (stands for bytesize) that makes the difference (…always does doesn’t it ;-).

Autopsy – The forensics browser always uses the ~/.autopsy as the base directory for storing the files from the cases. The following command is helpful in changing the directory in which the cases should be stored:

./autopsy -d /mountpoint/dirname

The exiftool is a cool application that can read meta-information to determine the different types of files.