This worm is related to Slapper. For more information on
Slapper, see http://www.f-secure.com/slapper/
This worm was found on Monday the 30th of September 2002. It is known as
Linux.Devnull. Some security vendors are calling it Linux.Slapper.D, although
the only thing it has common with Slapper is that it uses the same vulnerability.
This worm, once the host has been compromised, downloads and executes a
shell script from a web server. This script downloads an gzipped executable
file from the same address, it then decompresses and runs the file.
This downloaded file appears to be an IRC client, it connects to different
channels and waits for commands to process on the infected host.
Above: a screenshot of the IRC channel used by the worm for remote control
of infected machines. The channel had hundreds of bots, each representing
one infected machine.
After this, the script downloads another compressed file which contains an
executable and a C source code file. It tries to compile the source and runs
the executable. The executable will scan for vulnerable hosts and it will use
the compiled program to exploit the the known OpenSSL vunerability.
We are currently trying to remove these files from the web server - once this
is done, the worm shouldn't be able to spread further. The files seem to be
available on a server of a Japanese University.
If a vulnerable host is found it will send the script file and execute it
remotely. Then the decribed process starts in the new infected host.
This worm doesn't create a P2P network as Slapper did.
[Analysis: Ero Carrera, F-Secure, September 30th, 2002]