Re: is it possible to edit archivelog files?

Cute question.

Now that you mention it, it is pretty easy to hack a log file - for example changing a transaction that says

    debit X $100
    credit Y $100
to

    debit X $100,000,000
    credit Y $100,000,000

The problem is that you'd have to know which tables held all the application dependent implementation details - perhaps you have to change to other entries to cater for a sum being kept, and four more to cater for an audit trail being kept, and so on.

You would also have to know that the two bytes you needed to change were based on the current values in block NNN of file MMM to start with, perhaps cross checking that the 'transfers' table really was object_id 12345.

So, although it is easy to hack the log file self-consistently, your hacker would have to know the application and physical distribution of the database so well that hacking the log file would be the hard way of getting the job done.

--
Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

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Wijbrand Pauw wrote in message ...


>Hi,

>

>I work at al large bank and we want to get on Unix-Oracle the highest

>possible classification on availability and integrety.

>

>You all know the expressions that one fool can ask more questions

than 100


>wise man can answer, well than our security officer is a fool.....

>

>He now wants to know if it is possible to edit/change an

archivelogfile and


>then apply it to an standby database.

>We are doing a checksum on the files on the production and standby

machine


>before applying, for what that's worth.

>He wants to know because he wants to be very sure that someone can't

fake a


>disaster on production, going to the standby database, bringing it up

and


>there are for example new financial transactions (there will be over

>$50.000.000.000,- transferred every day) which weren't in the orignal

>production environment (that one is for example completly destroyed).

>

>

>I know that this sounds perhaps a bit silly or overdone but they want

to


>know.

>So is there a chance that someone can hack the archivelog files and

the file


>still be accepted by the standby database?

>

>Can you think of other potential dangers of changing the standby

database


>without being noticed (of course the database will remain in standby

mode


>but it is also used in ready only)?

>

>Thanks for your reply!

>

>Regards,

>

>Wijbrand