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Java Programming [Archive] - Secure Deletion of Character Array
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Posts:14,142
Registered: 99-04-02
Re: Secure Deletion of Character Array  
Aug 3, 2004 7:47 AM (reply 15 of 24)



 
security is somewhat like sex: abstinance is the only guaranteed method of prevention
 

Posts:1,183
Registered: 1/23/02
Re: Secure Deletion of Character Array  
Aug 3, 2004 7:58 AM (reply 16 of 24)



 
the attacker only has access to the memory of your machine after the password is processed ?

There are two considerations. The most common one is that the attacker makes your process dump core, then uses a separate attack to read the core file. If the password exists in memory for only a brief moment this attack becomes impractical.

The second one is a general/theoretical weakness of any multi-level security system. In any flawlessly implemented MLS system there is still some bandwidth to leak information downwards. The better implemented the system, the smaller the bandwidth. If information exists only briefly it becomes impractical to leak it using the available bandwidth.
 

Posts:2,830
Registered: 9/1/03
Re: Secure Deletion of Character Array  
Aug 3, 2004 3:06 PM (reply 17 of 24)



 
I would imagine that it's fairly unlikely scenario,
but not impossible. For example, if this is a shared
computer, the person who comes up behind me may peek
around memory after my program has completed, and if
no other program has incidentally overwritten those
chars, the attacker can find them.

even still if that was me doing the attacking I certainly wouldn't be trying to
dump the memory from your machine, I would just install a little program
to trap the password as you enter it in, or something similar. much easier.
 

Posts:2,830
Registered: 9/1/03
Re: Secure Deletion of Character Array  
Aug 3, 2004 3:09 PM (reply 18 of 24)



 
the attacker only has access to the memory of your
machine after the password is processed ?

There are two considerations. The most common one is
that the attacker makes your process dump core, then
uses a separate attack to read the core file.

but in this seperate attack (assuming it doesn't give access only
to this core-dump) couldn't they do something much more interesting?

but yes, if somehow the attacker can force your os to write everything
in memory out then it's probably not a great idea to hold the password
around for a long time.
 

Posts:1,183
Registered: 1/23/02
Re: Secure Deletion of Character Array  
Aug 3, 2004 3:25 PM (reply 19 of 24)



 
but in this seperate attack (assuming it doesn't give access only to this core-dump) couldn't they do something much more interesting?

Getting at the core dump is usually much easier than getting more general access. The number of links for http://www.google.com/search?core+dump+vulnerability speaks for itself :-)
 

Posts:1,183
Registered: 1/23/02
Re: Secure Deletion of Character Array  
Aug 3, 2004 3:28 PM (reply 20 of 24)



 
The number of links for http://www.google.com/search?core+dump+vulnerability speaks for itself :-)

This was unintentionally funny. A well-formed link works better http://www.google.com/search?q=core+dump+vulnerability
 

Posts:1,577
Registered: 00-02-25
Re: Secure Deletion of Character Array  
Aug 3, 2004 3:34 PM (reply 21 of 24)



 
At some point the passwords enters memory in plain
form and that must be a weak point.

Well, you could catch the keystrokes and hash them as they're input. But how do you know that someone hasn't put a low-level interceptor on your keyboard driver? Or isn't picking up the electrical signals transmitted from your keyboard? Or even the electrical signals generated by your CPU while you're processing the password?.

Perhaps you'd best build yourself a Tempest room that's physically secured.

Or just lock up the root/administrator password so that people can't read the contents of memory.
 

Posts:1,183
Registered: 1/23/02
Re: Secure Deletion of Character Array  
Aug 3, 2004 3:44 PM (reply 22 of 24)



 
Or just lock up the root/administrator password so that people can't read the contents of memory.

Unfortunately that's still not very secure. For one, it won't prevent an attacker from sneaking up and beating you about the head with a frying pan.
 

Posts:6,750
Registered: 1/25/04
Re: Secure Deletion of Character Array  
Aug 3, 2004 3:44 PM (reply 23 of 24)



 
Well, you could catch the keystrokes and hash them as
they're input. But how do you know that someone hasn't
put a low-level interceptor on your keyboard driver?
Or isn't picking up the electrical signals transmitted
from your keyboard? Or even the electrical signals
generated by your CPU while you're processing the
password?.

Or isn't looking over your shoulder as you type?
 

Posts:6,750
Registered: 1/25/04
Re: Secure Deletion of Character Array  
Aug 3, 2004 3:45 PM (reply 24 of 24)



 
Hm, I guess was a hair late on the meatspace joke.
 
This topic has 24 replies on 2 pages.    « Previous | 1 | 2 |