[CentOS] Antivirus for CentOS? (yuck!)
jkinz at kinz.org
jkinz at kinz.org
Thu Jan 22 02:38:34 UTC 2009
On Thu, Jan 22, 2009 at 12:19:27PM +1100, Amos Shapira wrote:
> Hi All,
> Yes, I know, it's really really embarrassing to have to ask but I'm
> being pushed to the wall with PCI DSS Compliance procedure
> (http://en.wikipedia.org/wiki/PCI_DSS) and have to either justify why
> we don't need to install an anti-virus or find an anti-virus to run on
> our CentOS 5 servers.
> Whatever I do - it needs to be convincing enough to make the PCI
> compliance guy tick the box.
> 1. Has anyone here gone though such a procedure and got good arguments
> against the need for anti-virus?
Amos - the best argument I have ever seen along those lines is
here : (And its a good one )
All UNIX/Linux aficionados should be familiar with its content.
FAIR WARNING, It is long and complex. Because it is
comprehensive and detailed. Those among you familiar with Rick
Moen will understand and appreciate why.
A portion pasted here:
The most recent version of these essays can be found at
Virus . . .
o Should I get anti-virus software for my Linux box?
o But didn't security expert Simson Garfinkel say that
all Linux systems need virus checkers?
o Don't the rise of Linux worms show that Linux now has
a virus problem?
o Isn't Microsoft Corporation's market dominance,
making Linux an insignificant target, the only reason it doesn't
have a virus problem?
o But how can you say there's no virus problem, when
there have been several dozen Linux viruses?
Should I get anti-virus software for my Linux box?
The problem with answering this question is that those
asking it know only OSes where viruses, trojan-horse programs,
payloads, and ordinary misbehaved applications are a constant
threat to their computing. Therefore, they refuse to believe
Linux could be different, no matter what they hear.
And yet it is.
Here's the short version of the answer: No. If you simply
never run untrusted executables while logged in as the root user
(or equivalent), all the "virus checkers" in the world will be at
best superfluous; at worst, downright harmful. "Hostile"
executables (including viruses) are almost unfindable in the
Linux world — and no real threat to it — because they lack
root-user authority, and because Linux admins are seldom stupid
enough to run untrusted executables as root, and because Linux
users' sources for privileged executables enjoy paranoid-grade
scrutiny (such that any unauthorised changes would be detected
Here's the long version: Still no. Any program on a Linux
box, viruses included, can only do what the user who ran it can
do. Real users aren't allowed to hurt the system (only the root
user can), so neither can programs they run.
Because of the distinction between privileged (root-run)
processes and user-owned processes, a "hostile" executable that a
non-root user receives (or creates) and then executes (runs)
cannot "infect" or otherwise manipulate the system as a whole.
Just as you can delete only your own files (i.e., those you have
"write" permission to), executables you run cannot affect other
users' (or root's) files. Therefore, although you can create (or
retrieve), and then run, a virus, worm, trojan horse, etc., it
can't do much. Unless you do so as "root". Which it's simple to
This is just the beginning - it continues on to cover every
aspect of the issue in a mere 1100 lines....
All of it well worth reading.
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