[CentOS] rkhunter and prelink

Wed Aug 30 16:03:40 UTC 2017
Valeri Galtsev <galtsev at kicp.uchicago.edu>

On Wed, August 30, 2017 10:43 am, Tony Schreiner wrote:
> This has come up for me on the most recent upgrade, add the line
> HASH_CMD=sha1sum
> On Wed, Aug 30, 2017 at 11:15 AM, <m.roth at 5-cent.us> wrote:
>> Can't remember if I posted this before... We're getting warnings from
>> rkhunterWarning: Checking for prerequisites               [ Warning ]
>>    All file hash checks will be skipped because:
>>    This system uses prelinking, but the hash function command does not
>> look like SHA1 or MD5.
>> Now, googling, I find people saying to rm /etc/prelink.cache, then run
>> rkhunter --propupd.
>> Works. And then, prelink runs in the middle of the night, via
>> /etc/cron.daily, and when the cron job of rkhunter runs, it's back to
>> complaining.

Prelink is evil, in a sense of what it does. Allegedly it helps to load
into memory binaries and libraries faster, for that it TOUCHES every one
of them regularly. This effectively defeats the way we watch for system
integrity by tracking all system files and libraries information, such as:
file sizes, time stamps, inode numbers, checksums. The very moment RedHat
made prelink installed by default, I was so upset that you can feel these
my feelings in my writing now are still present. I got rid of prelink, and
I rid of it specifically on my kickstart files. Two or three years down
the road RedHat came to its senses and removed prelink from what is
installed by default. I'm surprised, Mark, that you still have it some
place. Any specific reason? If not, get rid of prelink which does waaay
more harm than it does good IMHO.


>> Anyone have any ideas what's going on here? I don't see anything in the
>> prelink.conf, or any options in the prelink manpage to tell is what hash
>> to use.
>>      mark
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Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247