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Re: What is the best way to manage 3rd party debs?



martin f krafft wrote:
> If you install a third party deb, you should inspect its contents
> exactly to make sure it doesn't touch files in /etc. Also check the
> hooks. If there are no problems, then it's probably safe.

Did you know that dpkg will not install /var/lib/dpkg/info/* if it's in
the package's data.tar.gz? I'm sad that I cannot give that as an example
of an attack such checks will miss, but including files in /dev/* is nearly
as much fun. /proc/acpi/sleep is an amusing file to ship in a deb too.

If you want to run arbitrary code, you need to be more sneaky.. Shipping
a /root/.bashrc or /usr/local/bin/cat is too obvious, instead you can
ship a /lib/i486-linux-gnu/somelib.so. (The linker won't use it until
something else eventually runs ldconfig but this just hides that your
package is what causes the eventual breakage.) 

Be sure to include some /var/run/*.pid files, with a pid of 1 of course,
so that stopping daemons causes the system to reboot. Including 
a /tmp/.X11-unix/X0 will mess up the running X nicely.

BTW, including /bin/sh in a package won't work due to overwrite
checking, but you can include /usr/bin/awk and replace the symlink to
alternatives, since that symlink is not in a package. Finally,
installing a 'sl' or other typo-squatting command is always an option.

If these examples didn't make sense to someone, don't install third party
packages from untrusted sources, no matter how much checking you do..

-- 
see shy jo

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