Bugtraq mailing list archives

Disabling SunOS kernel module loading (Was: Re: Anti Hijacking tools)


From: Jeff.Smith () dcs warwick ac uk (Jeff Smith)
Date: Tue, 7 Feb 1995 22:22:31 +0000 (GMT)


    This program disables and open and ioctl of /dev/vd thus
    blocking modload and modstat from from funtioning.  The
    use of this is to disable people (crackers) from installing
    "unwanted" drivers.

As far as SunOS 4.1.X security is concerned, you are probably better off 
disabling loadable modules altogether by commenting out the

options        VDDRV           # loadable modules

line in the kernel configuration and linking in the loadable
modules that you want in a permanent fashion, as though they
were ordinary device-driver object files. Also, once you've done
this, you can delete (or at least de-suid) /usr/kvm/modload.

I haven't tried this with evqmod-sun4*.o or winlock-sun4*.o, (I don't
use them, though I would be interested in experiences). However, I
have done it with a frame-buffer loadable module, and in general it
should work unless the module has been written such that the act of
loading/unloading does something that would be traditionally
associated with first opens or last closes.

--
Jeff Smith, Computer Science, Warwick University, Coventry, CV4 7AL, England
jeff () dcs warwick ac uk       phone: +44 203 523485   fax: +44 203 525714



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