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Security in the 20-teens

Security in the 20-teens

Posted Feb 2, 2010 2:47 UTC (Tue) by dlang (subscriber, #313)
In reply to: Security in the 20-teens by smoogen
Parent article: Security in the 20-teens

but you can get that sort of security between machines. It's not cheap (it requires that you buy real application firewalls, not just cisco, checkpoint, linux, or *bsd stateful packet filters) and it requires that you take care about what your software is doing, but it is possible.

you do not get the same security by putting everything on one box and waving the SELinux magic wand.

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Security in the 20-teens

Posted Feb 3, 2010 13:37 UTC (Wed) by foom (subscriber, #14868) [Link]

But, once the firewall is parsing application traffic, who's to say it doesn't have the security holes
just like the application does? (Wireshark certainly has its fair share of remote exploits, for

Security in the 20-teens

Posted Feb 3, 2010 16:41 UTC (Wed) by dlang (subscriber, #313) [Link]

yes, any checking the firewall does opens the firewall up to the possibility of errors (this includes the checking done in stateful packet filters)

However, for all relatively sane protocols, there is checking that can be done that doesn't require as much code (and therefor doesn't have the risk) of the application code that will be processing the request. Properly done the code for the firewall is relatively static and can be well tested. It doesn't need to change every time you add a new function to the application (or change it's behavior), it only needs to be able to be configured to do different checking.

Usually this can be things like (in order of increased complexity)

checking that the message is well formed by the definition of the protocol

checking that the message follows the protocol syntax

checking that specific fields in the message are in a whitelist

Yes Wireshark has a horrible track record in security, but this sort of checking is happening in many firewalls (under names like 'deep packet inspection') for some protocols. There are also seperate 'Application Firewall' products you can get for some protocols. The better IDS/IPS systems do this sort of thing (as opposed to mearly blacklisting known exploits)

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