[aprssig] Secutiry for the aprs protocol and software

[Matti Aarnio]

On Wed, Aug 26, 2009 at 03:32:24PM -0700, Scott Miller wrote:
> And basically we just have to hope that Roger was as vigilant with  
> UI-View, since we don't have any way to check.

Indeed.  Unmaintained software without sourcecode should not be used for
anything sensitive, or a large effort should be put on to decompile it..

...
> There's a lot of string parsing going on in an APRS client, and lots of  
> rules and exceptions to rules to follow.  That makes a lot of possible  
> targets for data driven attacks.

Been there, seen surprises....  (it was an other protocol, but careless
parsing is careless parsing...)

...
> Some aspects of the system just don't lend themselves to securing.  For  
> example, you can generate a packet on the air that has a CR/LF pair and  
> a fake second packet in TNC-2 format grafted on.  By the time it gets to  
> an IS client, there's no way to tell that it wasn't two legitimate  
> packets.  Not that that really matters since you can spoof packets all  
> day anyway, but it might at least get you past filters on an IGate.

This is why I recommend using KISS protocol when reading packets from
TNC to computer.  Then you chop the payload at first LF, and such easter-
eggs are impotent.  (There should be no CR/LF within the APRS packet
on RF.)

> Scott
> N1VG

73 de Matti, OH2MQK