Date: Wed, 10 Mar 2010 15:09:43 -0800 From: Julian Elischer <julian@elischer.org> To: Elmar Stellnberger <elmstel@gmail.com> Cc: freebsd-security@freebsd.org Subject: Re: online cheksum verification for FreeBSD Message-ID: <4B9826B7.1080304@elischer.org> In-Reply-To: <4B97C1D1.7050209@gmail.com> References: <4B97AB28.8060403@gmail.com> <20100310185328.GD37825@server.vk2pj.dyndns.org> <4B97C1D1.7050209@gmail.com>
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Elmar Stellnberger wrote: >>> The only thing that I have found about it is: >>> "DS Compare the system against a "known good" index of the installed >>> release.'" >> As well as freebsd-update(8), the FreeBSD base system includes >> mtree(8) - which can be used to generate and check file hashes. Other >> tools, such as tripwire, are available in the ports tree. >> > > As far as I am informed freebsd generates the checksums right after > installation. However this is absolutely useless for a tool like > checkroot that aims at an online checksum verification. > > >> On 2010-Mar-10 15:22:32 +0100, Elmar Stellnberger <elmstel@gmail.com> > wrote: >>> I believe it would be highly desireable to have an online md5sum >>> verification for FreeBSD as this is already implemented by checkroot >>> (http://www.elstel.com/checkroot/) for openSUSE. >> You are welcome to adapt your tool to support FreeBSD and have it >> included in the ports system. > > Could anyone help me in how to obtain online cheksums (md5 or better > sha1) for the files of every installed package? > > >> That said, it's unclear that your tool offers any benefits over >> the freebsd-update(8) tool that is part of the FreeBSD base system. >> > > You seem to be really ignorant about the issues I have pointed out about > online/offline cheksums: > * offline cheksums require some security tool having been installed in > advance. > Most users simply don`t have tripwire or sth. else installed but are > nonetheless > possible targets for crackers. > * offline cheksums are very tedious to maintain: > They require a full system verification in advance to any new update > being followed > by a new checksum backup > If you just forget that once you can throw your system away. > Now do also think about applying a single update or about updating > regularely > which should be recommended for reasons of security. > > >> Note that an >> intruder could equally easily modify the checkroot executable unless >> it is also stored on read-only media. > > Yes I have clearly pointed this out on my web site. The tool will of > course not be useful as long as it is not invoked fromout of a boot CD. > Concerning me I do always have a current boot CD handy - and be it just > for reinstalling the boot loader. > > >> I notice that your tool only appears to store MD5 hashes - I presume >> you are aware that the MD5 algorithm has been shown to have a number >> of weaknesses and is not recommended for new applications. This >> is why FreeBSD has moved to using a combination of MD5 and SHA256. > > Yes, we should use SHA-1 (or possibly a combination of SHA-1 and MD5) > for FreeBSD. > For openSUSE I had to use what has been available. > > _______________________________________________ > freebsd-security@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-security > To unsubscribe, send any mail to "freebsd-security-unsubscribe@freebsd.org" all that is not to say it's a bad idea, just that people are interested to see what the advantages are etc.
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