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Known-Good MD5 Database
bgp4 writes "Have you ever examined a system you thought was broken into but you weren't sure? If only you had run an integrity verification program like osiris or Tripwire first you could have figured out what programs had been changed. In an effort to help out in the instances when you can't answer the question "what was this like before?" we've constructed a searchable database of MD5 and SHA-1 hashes for files in many standard operating systems. You can search using the filename or the checksum and see if you have a trojaned binary or an overactive imagination. Currently at knowngoods.org we have many FreeBSD, OS X, Linux, and Solaris installations checksummed and cataloged. If you have other programs or distributions you would like to see in the database, please let us know."
What they don't say and what a lot of security folks forget to do is that they can't check your checksums of binaries on the same box. You need to copy the files to another box and check the checksums there with a known good version of your checksumming binary. The local version of your checksumming binary could have been compromised.
Heck, the utilities you used to pull the binary off the machine in question could have been compromised and may not be actually copying the binary in question, but a good version of the binary. The only way to check this would be to mount the drive on another machine and check it there... And if people aren't doing that (which it's a pain in the ass) all this website is going to do is give people a false sense of security.
All editorial writers ever do is come down from the hill after the battle is over and shoot the wounded.
A few months ago I put together a list of the "polymorphic" files in FreeBSD 4.6:
These files are always going to set off alarms if you've upgraded-by-source. (On the other hand, if a file *not* on this list has a different checksum, it probably just means that you've applied a security patch.)
Tarsnap: Online backups for the truly paranoid
Boot from a known good floppy or CD to check your md5sums.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Debian has this built into the OS with debsums.
It does require a legit dpkg database (and md5sum, and the debsums program itself...) but it's a nice tool.
NIST (The National Institute of Standards and Technology) currently has a program to provide this service, though largely focused on Microsoft OSes and associated apps. It may be found here: National Software Reference Library
The complete list of software they've checksummed can be found here: Software Listing or you can use their search engine if you're looking for a specific application here: Search Engine
For Red Hat-based systems, at least, rpm -V will do pretty much exactly what you're looking for.
... The (mnemonically emBoldened) character denotes failure of the corresponding --verify test:
/etc/php.ini
/etc/httpd/conf/httpd.conf /var/www/html/index.html /var/www/html/poweredby.png
:)
From the man page for rpm:
The general form of an rpm verify command is
rpm {-V|--verify} [select-options] [--nodeps] [--nofiles] [--nomd5] [--noscripts]
Verifying a package compares information about the installed files in the package with
information about the files taken from the package metadata stored in the rpm database. Among other things, verifying compares the size, MD5 sum, permissions, type, owner and group of each file. Any discrepencies are displayed.
S file Size differs
M Mode differs (includes permissions and file type)
5 MD5 sum differs
D Device major/minor number mis-match
L readLink(2) path mis-match
U User ownership differs
G Group ownership differs
T mTime differs
So while that's a bit cryptic, a shell script run once every x days (30? 14?) should tell you what files have changed. All you would have to do is run rpm -qa to grab a list of the packages in your system, and then loop through the list and run rpm -V for each RPM returned.
For instance, running rpm -V on two common packages, Apache and PHP, shows me the following:
# rpm -V php
S.5....T c
(php.ini has changed... which in this case means I've tweaked some of PHP's default settings.)
# rpm -V apache
S.5....T c
missing
missing
(Okay, I've changed httpd.conf, again pretty much a given, and I've removed a couple of the default files.)
I guess this website seems pretty unneeded to me. Granted, the above is just for RPM-based systems, but I'm sure Debian and ports have similar options. And to the people who have installed from source and say "What about me?", I say, first, never underestimate the power of a package management system, and second, check out CheckInstall, which allows you to create an RPM or DEB just by saying "checkinstall" instead of "make install". If you feel you must compile from source, checkinstall is a necessity! Using checkinstall gives you all the benefits of a package management system while still allowing for the flexibility that compiling from source provides.
Between checkinstall and up2date, I'm a very happy Red Hat customer. I just wish more people knew about some of the truly powerful things in package management systems (such as the verify command detailed above.) Package management systems are there for a reason. Use them!
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Sun already provides this for Solaris.
s .p l
http://sunsolve.Sun.COM/pub-cgi/fileFingerprint
It contains information for:
Operating Systems
Solaris SPARC - 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.5.1, 2.6, Solaris 7 and Solaris 8
Solaris x86 - 2.1, 2.4, 2.5, 2.5.1, 2.6, Solaris 7 and Solaris 8
Solaris PPC - 2.5.1
Trusted Solaris SPARC - 2.5, 2.5.1 and 7
Trusted Solaris 7 x86
Most CDs bundled with Solaris 2.6 and later.
Patches
Nearly all released Solaris patches, including all SunSolve CDs to date. (4.0.11)
All Solaris 2.6/7 Maintenance updates.
All patches available from SunSolve.
Unbundled Products
Around 150 CDs with unbundled products are included. If you are missing any particular product, please feel free to send email and we will try to include it as soon as possible.
Unless your compiler, linker, assembler, libraries, or source code have been modified.
Sheesh, dosen't anyone read old ACM articles?
http://www.acm.org/classics/sep95/
At some point, unless you build your system from scratch, cross compile on multiple systems, burn your own BIOS ROM, and write the microcode for your NIC and all other interface devices, you are trusting *SOMEONE ELSE* for the security of your system.