[CentOS] Antivirus for CentOS? (yuck!)

Les Mikesell lesmikesell at gmail.com
Thu Jan 22 21:00:43 UTC 2009


Adam Tauno Williams wrote:
>
>> What do you do with clamav on a linux server? 
> 
> You scan the server for malware.  
> 
> There is nothing special about LINUX here.  The whole "don't run
> services as root" business is just so much noise.  It isn't about
> protecting the *server* it is about protecting the *data* which is
> accesses [hopefully] by services which are *not* root.  It is about the
> data and the clients that connect to the server.   

Yes, but the scan has to be specific for the kind of problem you want to 
detect.

> I've seen CLAMAV find malware on web servers (maybe it isn't common...
> because no one is checking).  Someone's crappy PHP code [is there any
> other kind?] allows malware to get injected into, and served, from the
> server.

That tends to be more because someone isn't doing updates than that they 
aren't checking.  Before a scan can help you, the scanner has to know 
about the problem.  After someone knows about the problem there will 
likely be an update to fix it at least as soon as a scanner that will 
detect it after the fact.  Which makes more sense to install?

> No root access anywhere, or required.  It isn't about
> protecting the OS or the system, it is about protecting the data, the
> applications [from exploit], and the end-users [so the server isn't an
> attack vector].   Assuming none of the services on you server can be
> exploited is just wrong headed;

But expecting a scanner to know about the exploit long before the 
exploit is known and fixed seems misguided as well.

>  and the exploiter does not need to
> "own" the server (aka have root) in order to do mischief.   Access to
> your data is probably more valuable than whacking your server.
> 
> The mantra "LINUX doesn't suffer from malware" is just bollocks.  Lots
> of malware is served from LINUX servers.

That may be true, but the exploit that allowed it to be put there may be 
unrelated.  For example, you may have virus-laden email being 
transported through a Linux server that doesn't have anything else to do 
with it.  Or you may have a samba share where windows clients can infect 
it.  Or, someone might get access through brute-force ssh password guessing.

> Scanning a server for
> signatures is just another way to proof (not prove) that a server has
> not been compromised and that data accessed by the server is secure.
> Which is what things like PCI/DSS is about - protecting the *data*. 

An occasional clamav scan can't hurt.

>>  What do you think it protects you against on a linux server? 
> 
> "against a linux server?" ?

Doing frequent updates is what keeps you safe - and maybe turning off 
ssh password access.

-- 
   Les Mikesell
     lesmikesell at gmail.com


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