How to corrupt a db

Question

How to corrupt a db

Frank Kalis

SSC Guru

Points: 111183
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June 10, 2003 at 5:13 am

#80366

Hi all,
for testing purposes is there a way to corrupt a db via T-SQL or something else?
Cheers,
Frank
--
Frank Kalis
Microsoft SQL Server MVP
Webmaster: http://www.insidesql.org/blogs
My blog: http://www.insidesql.org/blogs/frankkalis/[/url]

Viewing 15 posts - 1 through 15 (of 19 total)

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mccork SSC-Insane Points: 22288 More actions · Answer 1

In SQL 6.5 (and sybase) I recall a "DBCC CORRUPT" command, for training purposes. But I also think the database had to be called "corrupt". I'll investigate further...

Cheers,
- Mark

mccork SSC-Insane Points: 22288 More actions · Answer 2

...further to that, the database had to be called "victimdb" but no longer works on SQL2k anyway. You can stop mssqlserver and then play around with a hex editor in the mdf file until you get the sort of corruption you're after? For instance, if you change the first byte it'll go straight into suspect mode upon SQL Server startup with an "invalid header" message, but you may have to experiment a bit to get something a bit more subtle.

Cheers,
- Mark

Frank Kalis SSC Guru Points: 111183 More actions · Answer 3

Hello Mark,

quote:
works on SQL2k anyway. You can stop mssqlserver and then play around with a hex editor in the mdf file until you get the sort of corruption you're after?

of course changing something in hex will corrupt a db. If not done properly, this will crash every kind of file. But that's nothing what someone would unintentionally do. What I'm after is why, which and how T-SQL Statements can corrupt a db. Where are the pitfalls, how can I prevent, and how can I rescue the db?

Cheers,

Frank

--
Frank Kalis
Microsoft SQL Server MVP
Webmaster: http://www.insidesql.org/blogs
My blog: http://www.insidesql.org/blogs/frankkalis/[/url]

MarkusB SSC-Dedicated Points: 37370 More actions · Answer 4

Here you have a script which corrupts the IAM of a table. Note that after running the script the table in question is longer accessible while the database status remains online.



sp_configure allow, 1

go

reconfigure with override

go

update sysindexes set FirstIAM = 1234

where id = OBJECT_ID('roysched')

go

sp_configure allow, 0

go

reconfigure with override

go

[font="Verdana"]Markus Bohse[/font]

David Burrows SSC Guru Points: 65142 More actions · Answer 5

Interesting!

Hope there aren't any unscrupulous DBA's with a company grudge reading this.

Far away is close at hand in the images of elsewhere.
Anon.

Frank Kalis SSC Guru Points: 111183 More actions · Answer 6

It seems that if you can't trust your DBA's, you'll have a problem...

quote:
Interesting!
Hope there aren't any unscrupulous DBA's with a company grudge reading this.

maybe something to use on the next compensation discussion?

Cheers,

Frank

--
Frank Kalis
Microsoft SQL Server MVP
Webmaster: http://www.insidesql.org/blogs
My blog: http://www.insidesql.org/blogs/frankkalis/[/url]

Frank Kalis SSC Guru Points: 111183 More actions · Answer 7

Hello Markus,

quote:
Here you have a script which corrupts the IAM of a table. Note that after running the script the table in question is longer accessible while the database status remains online.

thanks, I will try it in the next days!

...and surely come up with follow-up questions

Cheers,

Frank

--
Frank Kalis
Microsoft SQL Server MVP
Webmaster: http://www.insidesql.org/blogs
My blog: http://www.insidesql.org/blogs/frankkalis/[/url]

kevin-66223 Valued Member Points: 63 More actions · Answer 8

kevin-66223

Valued Member

Points: 63

June 11, 2003 at 4:52 am

#460724

If you want you can have mine!

Crispin Proctor SSCoach Points: 18161 More actions · Answer 9

I found a way to corrupt a DB.

It works on 7 and 2000.

Give it to a user / client.

Cheers,

Crispin

Cheers,CrispinI can't die, there are too many people who still have to meet me!It's not a bug, SQL just misunderstood me!

Frank Kalis SSC Guru Points: 111183 More actions · Answer 10

Hello kevinbrowne,

quote:
If you want you can have mine!

no chance, just the way how you did it.

Did you allow any user access, as Crispin mentioned???

Cheers,

Frank

--
Frank Kalis
Microsoft SQL Server MVP
Webmaster: http://www.insidesql.org/blogs
My blog: http://www.insidesql.org/blogs/frankkalis/[/url]

spongemagnet SSCrazy Points: 2812 More actions · Answer 11

"For testing purposes, is there a way to corrupt a db via an .ASP page over http?"

Edited by - spongemagnet on 06/11/2003 3:03:12 PM

-Ken

Frank Kalis SSC Guru Points: 111183 More actions · Answer 12

Hello spongemagnet,

quote:
"For testing purposes, is there a way to corrupt a db via an .ASP page over http?"

don't get me wrong, but I hope there isn't an (at least easy) answer to your question!

Cheers,

Frank

--
Frank Kalis
Microsoft SQL Server MVP
Webmaster: http://www.insidesql.org/blogs
My blog: http://www.insidesql.org/blogs/frankkalis/[/url]

BrandonGalderisi Newbie Points: 1 More actions · Answer 13

BrandonGalderisi

Newbie

Points: 1

June 12, 2003 at 10:05 am

#461085

This didn't work for me.... any suggestions?

zach_john SSCertifiable Points: 5922 More actions · Answer 14

Kill a long running transaction and while it's rolling back out pull the plug on the server. That's what one of my former clients did. (they didn't have a viable backup either) Big name outfit too.

John Zacharkan