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Passwd Files

Saturday, 30 July 2005 security unix

Introduction

Passwd files are the easist and simplist ways to hack. This text will explain what they are, how to get them, how to crack them, what tools you will need, and whatyoucan do with them. Of course the minute you sign on the account you just happened to crack because of this file, you are breaking the law. This text is for information, not illegal activites. If you choose to doillegal activies with the information from this it is no one’s fault but your own. Now down to the good stuff.

What is a Passwd File

A passwd file is an encrypted file that contains the users on aservers passwords. The key word here is encrypted, so don’t start thinking all i have to do is find one and i hit the jackpot. Nope sorry Man, theres alot more to it than that. The passwd file should look something like this

root:x:0:1:0000-Admin(0000):/:/bin/ksh  
daemon:x:1:1:0000-Admin(0000):/:  
bin:x:2:2:0000-Admin(0000):/usr/bin:  
listen:x:37:4:NetworkAdmin:/usr/net/nls:nobody:x:60001:60001:uid  
nobody:/:noaccess:x:60002:60002:uid noaccess:/:  
ftp:x:101:4:  
FTPUser:/export/home/ftp:  
rrc:uXDg04UkZgWOQ:201:4:RichardClark:/export/home/rrc

Out of that entire section the only name you could use would be rrc:uXDg04UkZgWOQ:201:4:RichardClark:/export/home/rcc and here’s how you interpret that:

Because it is the only name with an encrypted password. You will never find a passwd file that has a passwd for anything like ftp, listen, bin, etc., etc. Occasionally using the PHF exploit or unshadowing a passwd file you can get an encrypted password for root.

PHF Exploit

First let me explain what an exploit is. An Exploit is a hole in software that allows someone to get something out of it that… Well you aren’t supposed to. The PHF exploit is a hole in CGI, that most servers have fixed now (if they have CGI). Lets just say a very popular IRC place has a problem with their CGI. Also on the subject of servers with the exploit open, many forien servers have this open. Unlike the FTP Passwd you don’t even have to access their FTP or login. What you do is get a WWW browser and then in the plass for the WWW address type:

http://www.target.com/cgi-bin/phf?Qalias=j00%ffcat%20/etc/passwd

In www.target.com Place who’s passwd you want to get. If you get a message like ““The requested object does not exist on this server. The link you followed is either outdated, inaccurate,
or the server has been instructed not to let you have it.”” its not there. If you get ““You have been caught on Candid Camera!”” They caught you, but don’t fear they rarly ever Report you. I have yet to find a server that does report. Of course if you get ""root:JPfsdh1NAjIUw:0:0:Special admin sign in

:/:/bin/csh  
sysadm:ufcNtKNYj7m9I:0:0:  
Regular Admin login:/admin:/sbin/sh  
bin:\*:2:2:Admin :/bin:  
sys:\*:3:3:Admin :/usr/src:  
adm:\*:4:4:Admin :/usr/adm:/sbin/sh  
daemon:\*:1:1: Daemon Login for daemons needing  
nobody:\*:65534:65534::/:  
ftp:\*:39:39:FTP guest login:/var/ftp:  
dtodd:yYn1sav8tKzOI:101:100:John Todd:/home/dtodd:/sbin/sh  
joetest:0IeSH6HfEEIs2:102:100::/home/joetest:/usr/bin/restsh""

You have hit the jackpot [=. Save the file as a text and keep it handy, because you will need it for later in the lesson.

FTP Passwd

The Passwd file on some systems is kept on FTP, which can pretty much be accessed by anyone, unless the FTP has a non-anonymous logins rule. If you are desprite to get a passwd file from a certain server (which may not even be open, so only do if you are desprite or you want to hack your own server) get an account that allows you access to their FTP. What you do is get an FTP client such as WS FTP or CuteFTP. Find the servers name and connect to it. You should get a list of Directories like ““etc, hidden, incoming, pub”” goto the one called etc. inside etc should be a few files like ““group, passwd”” if any chance you see one called shadow there is a 8/10 chance you are about to deal with a shadowed passwd. Well get the passwd file and maybe check out what else is on the server so it won’t look so suspious. Anyway when you log out, run and check out your new passwd file. If you only see names like ““root, daemon, FTP, nobody, ftplogin,bin”” with * beside their names where the encrypted passwd should be, you got a passwd file that you cannot crack. But if it happens to have user names (like rcc:*: or ggills:*:“” with a * (or another symbol) you have a shadowed passwd. Of course if you have been reading and paying attention if you have something that has a few things that look like:
““joetest:0IeSH6HfEEIs2:102:100::/home/joetest:/usr/bin/restsh””
You have gotten one you can crack.

Shadowed Passwd’s

Now if you happen to find a passwd fiel that looks something like this: ““joetest:*:102:100::/home/joetest:/usr/bin/restsh””
which has a user name, not a programs, you have a shadowed passwd. The shadow file has the encrypted passwords on it. Depending on the Operating System, the passwd file may be in different places. To find out what Operating system your target is running from telnet (connected to that server ofcourse) type uname -a and it should say, if you cannot get to telnet there is other methods of finding out. Here is a guide to systems passwd file locations (taken from a text on passwd files by Kryto.) A token is the * (or other symbol) beside a shadowed passwds user name

UNIX Paths (Courtesy of 2600)

UNIX Path Token
----------------------------------------------------------------
AIX 3/etc/security/passwd !
or /tcb/auth/files/ A/UX 3.0s /tcb/files/auth/?/ * BSD4.3-Reno /etc/master.passwd * ConvexOS 10 /etc/shadpw * ConvexOS 11 /etc/shadow * DG/UX /etc/tcb/aa/user/ * EP/IX /etc/shadow x HP-UX /.secure/etc/passwd * IRIX 5 /etc/shadow x Linux 1.1 /etc/shadow * OSF/1 /etc/passwd[.dir|.pag] * SCO Unix #.2.x /tcb/auth/files/ / * SunOS4.1+c2 /etc/security/passwd.adjunct ##username SunOS 5.0 /etc/shadow System V Release 4.0 /etc/shadow x System V Release 4.2 /etc/security/* database
Ultrix 4 /etc/auth[.dir|.pag] *
UNICOS /etc/udb * Anyway once you have the passwd file (with user names) and shadow file you can find a unshadowing program which combines the passwd file and the shadow passwd and combines them into what a regualr passwd file would be. A unshadowing program can be found at http://www.hackersclub.com/km/downloads/password_cracker/ucfjohn2.zip Now some servers have the shadow file on retrictions so no one without a special account on the server can get to it.

Crackers

Now that you have gotten a passwd file, what the hell do you do it it to get passwords from it? Thats where crackers come in.
A cracker takes the passwd file and a wordlist and compares the wordlist to the passwd files encrypted passwd. I have used many different crackers. Everyone has their favorite. My personal favorite is one called PaceCrack95 Ver. 1.1
http://tms.netrom.com/~cassidy/utils/pacec.zip
Many people swear that John the Ripper is the greatest but i have problems with it, but it can be gotten off any decent hacking page. Same for Cracker Jack. A Cracker will load a wordlist and a passwd file and compare the two. When it cracks a password it will tell you the user name and the unencrypted password. You don’t need to write it down because the program auto saves it. Cracker Jack saves the file as jack.pot and i think John the Ripper does too. PaceCrack95 Ver. 1.1 saves it to the files name (ex., passwd.txt.db) with the exact name and makes it a .DB file. I like to keep a passwd file once i have cracked it and later try out a new passwd cracker on it with the same wordlist and see if it works or if it is fake. It helps.

Wordlists

Wordlists are a nessicity to cracking passwd files. They are just huge lists of words. The biggest wordlist is avaliable from here: ftp://ftp.ox.ac.uk/pub/wordlists/
If you get a passwd file from another contry get a wordlist with the same launguage as the worlist came from, as the users would probably use words they are familier with [=. There are some programs which can make random numbers to what you specify but that might not be really great, since there is such a huge amount of number combinations they could use. I am not completly saying they are useless since i have cracked a password with one before, I had fashoned my own list of 4 digit numbers since people might use their phone number and well it worked.

What to do with a Cracked Passwd file

What you can do with a passwd is up to you. The nice thing to do is inform the administator of the server that, accounts on his (or her) server are insucure and possibly open to anyone hacking an account and bringing havok upon their server. Some other things you can do is fire up good ole telnet and connect to one of their ports and see what you could do with that account. The possiblities are endless. You could hack a webpage (i wouldn’t do that on account of how lame it is to destruct someones piece of work.)
You could use an exploit in sendmail and get root or install a sniffer on the system and get all the passwords you could ever want from it. You could use the account to do work on OTHER servers that you sure as hell wouldn’t want to do from your own. If your account is canceled you can use a hacked accounts dial up till you purchase a new one. Like I said the list goes on and on. I am sure noone wants you doing anything destuctive (its lame anyhow.) And the best thing to do is report the problem to the system admin so, if he finds out he won’t freak and call your admin and tell him you have been doing naughty things or even call the cops. I hope this text was informative enough to fufill your needs.