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Re: 2.4.x/Slackware Init script vulnerability


From: twiz - Perla Enrico <twi () boiate it>
Date: Thu, 19 Jul 2001 01:50:07 +0200 (CEST)

As Josh make me notice i' m partial in error.
The problem was that i' ve installed kernel 2.4.5 on my box after
(Slakware 7.0 come with kernel 2.2.13) , so I gave make modules_install at
the end of the compilation : 

if [ -r System.map ]; then /sbin/depmod -ae -F System.map  2.4.5; fi

At the end depmod -a is called and it creates modules.dep, and it gives
"-rw-r--r--" permissions.
The Slakware startup script calls depmod -a, but modules.dep isn't erased
before, but just "updated", so it keeps "-rw-r--r--" permissions.
I' ve tried erasing modules.dep and then rebooting and modules.dep, this
time beeing created, has , as Josh, said "-rw-rw-rw" permissions.

So in the end this exploit will work only if the kernel hasn't benn
recompiled with make modules_install (or depmod -a called otherwise
not at the startup) of if modules.dep is erased before "depmod
-a" at the startup (Slakware 7.0 init script doesn' t do that, so it is
not vulnerable :) )

  I' m sorry for my partially erroneus post

    twiz - twiz () superdotati net or twi () boiate it - ./twlc


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