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Re: [opensuse-security] ISO Signatures

2008/6/14 Carlos E. R. <robin.listas@xxxxxxxxxxxxxx>:
> I'm sorry, I don't quite understand. The checksum for the ISO file checks
> the entire ISO file including the bootloader, so I don't see how the
> bootloader can be altered and the iso still pass the test.

There are MD5SUMs here
http://download.opensuse.org/distribution/10.3/iso/cd/MD5SUMS .
However, md5 has various weaknesses and it is potentially possible to
engineer a modified iso the same size with the same MD5SUM.
Furthermore, the md5sums are not even signed, so it's difficult to be
sure they are even correct.

Since the bootloader can do anything to your system and is untrusted,
it is potentially dangerous to boot from a downloaded openSUSE ISO.
The contents file and others itself inside the ISO are signed. I
believe it is possible to generate a fully trusted ISO by regenerating
the bootloader from signed material. It would be much simpler just to
publish signatures for the ISOs though.

Benjamin Weber
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