Re: Slapper questions

[Stephen Smoogen <smoogen () lanl gov>]

Its a bit late in the game, but you may have a backdoor (or various
backdoors) running on the system. My advice is to do the following (with
the assumption you only have 1 machine available to run the website).
[Sorry if it is a bit general, but its from a list I hand out to
completely new sysadmins working on compromised machines.]

A) Take the system off the network (letting management know why)
B) Backup the system to completely to tape in case you need to present a
   report to law enforcement or management (why I need to be paid  
   more or sent to that SANS training. :))
C) Go over what you need on this machine still (IE what code etc is
   running on it for webservices that may need to be audited to see if a
   back door was planted there.)
D) Reinstall the machine from source cdroms and then put all updates for
   that operating system on the machine. 
E) If your Linux vendor has an automated system of alerts or updates see
   if you can sign up for it or get your employeer to pay
   for it. 
F) Reinstall the software that you need for the website to be
   operational and test it for working.
G) Put the machine back on the network and test functionality again
H) Go over all that was discovered and write up a short report for your
   CYA file and to hand over to management over what happened, why, and
   what needs to be done in the future.

If you have multiple hardware and more than 1 staff you can parallelize
portions of C, D, E, and F. H sounds like a nuisance, but it can save
your job or worse.

On Wed, 2002-10-23 at 13:42, Griff Palmer wrote:
> Hello:
>
> I'm trying to learn more about how the Apache/mod_ssl worm variants operate.
>
> Last month chkrootkit discovered evidence of the Slapper worm on my RedHat 
> 7.2 server. I found .bugtraq.c in my /tmp directory and eliminated it. I 
> updated my openssl to 0.9.6g-1. I blocked port 443 on my firewall.
>
> I keep my ftp daemon stopped except for occasional short periods when I need 
> to use it. I've been leaving port 23 open and making my ssh host listen on 
> port 23. (My employer's firewall blocks traffic on port 22, forcing me to go 
> to the port 23 setup.)
>
> Regular scans with chkrootkit since then have shown no signs of the slapper 
> worm's presence. 
>
> This morning I received an e-mail bounce from cinik_worm () yahoo com 
> (apparently Yahoo has disabled that address). A search on cinik led me to the 
> latest CERT bulletin, which showed information about the slapper B and C 
> variants.
>
> After reading the bulletin I discovered the presence of cinik.c and cinik.go 
> in my /tmp directory, which I eliminated.
>
> I also discovered an active .bugtraq process on my machine and killed it.
>
> I've blocked UDP packets on ports 1812 and 1813. (Looking at the CERT 
> bulletin it looks as if I should also block 1978, 2002 and 4156.) I've 
> commented out the listen 443 line in my httpd.conf file.
>
> At this point I'm confused about the mechanics of the infection process and 
> about what further steps I may need to take to fully eliminate infection and 
> harden my server.
>
> Is Port 23 an avenue of infection? Does upgrading to openssl-0.9.6g-1 not 
> eliminate vulnerability to compromise? Is it possible that I missed the 
> C-variant code when I discovered the .bugtraq code, and that the C variant 
> code has lingered on my machine since then? I'm using chkrootkit-0.37. Is it 
> able to detect the B and C variants as well as A variants? 
>
> I've run ps on my machine many times since chkrootkit discovered the Slapper 
> A variant. Those checks showed no presence of the .bugtraq process. (I even 
> downloaded and installed new system binaries in case any of those had been 
> subverted.)
>
> The .bugtraq process showed up after I upgraded my kernel this morning. Is it 
> possible that my earlier kernel had been compromised and that the .bugtraq 
> process was being hidden?
>
> Any advice appreciated.
>
>                                                       Griff Palmer
>
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-- 
Stephen John Smoogen            smoogen () lanl gov
Los Alamos National Labrador  CCN-2 B-Schedule  PH: 
Ta-03 SM-261  MailStop P208 DP 17U  Los Alamos, NM 87545


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