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Re: Second day of rolling blackouts starts

  • From: Hank Nussbacher
  • Date: Sun Jan 21 08:16:37 2001 
At 09:43 19/01/01 -0500, Marshall Eubanks wrote:
Two people have asked me off list about the RAMEN worm,
which affects Linux Redhat distro's. Here is brief description of the
worm, and a link to more,
from Lucy Lynch at Internet2 / UOregon.

The multicast implications :

This worm scans a portion of the multicast address space. These scans (packets)
are viewed as new multicast sources by a PIM multicast enabled router,
which encapsulates
them and sends them to its RP. The RP creates MSDP Session Announcements
FOR EACH SCAN
and floods them to every RP neighbor it has in "nearby" AS's, and those
repeat the process.
The result is a MSDP packet storm. We have gotten 15,000 SA's a minute.
Dealing with these
can melt down routers. (We had to reboot a Cisco 7204, for example,
which apparently either filled
up or fragmented its memory beyond usability.)

I think it is fair to say that the question of rate limiting and other
DOS filtering in
PIM/SSM/MSDP multicast is getting serious attention now.
I have installed on my multicast tunnels (one to StarTap and the other to Dante/Quantum):

rate-limit input access-group 180 128000 30000 30000 conform-action transmit exceed-action drop
!
access-list 180 permit tcp any any eq 639
access-list 180 permit udp any any eq 639
access-list 180 deny ip any any

IANA has MSDP listed as port 639 - tcp+udp. It appears MSDP is only really TCP:
mcast#sho access-l 180
Extended IP access list 180
permit tcp any any eq 639 (1555 matches)
permit udp any any eq 639
deny ip any any (37888 matches)

and

mcast#sho in rate
Tunnel1 Mbone tunnel to Dante
Input
matches: access-group 180
params: 128000 bps, 30000 limit, 30000 extended limit
conformed 755 packets, 60044 bytes; action: transmit
exceeded 0 packets, 0 bytes; action: drop
last packet: 388ms ago, current burst: 0 bytes
last cleared 00:07:26 ago, conformed 1000 bps, exceeded 0 bps
Tunnel2 Mbone tunnel to Startap
Input
matches: access-group 180
params: 128000 bps, 30000 limit, 30000 extended limit
conformed 909 packets, 148937 bytes; action: transmit
exceeded 0 packets, 0 bytes; action: drop
last packet: 1048ms ago, current burst: 0 bytes
last cleared 00:08:48 ago, conformed 2000 bps, exceeded 0 bps

I'll only know tomorrow if I stop getting the constant:
Jan 21 14:00:03: %SYS-3-CPUHOG: Task ran for 6300 msec (123/75), process = MSDP Process, PC = 60790390. -Traceback= 60790398 604146B4 604146A0
error messages. I don't know whether 128kb/sec of MSDP is too much or too little.

-Hank



Marshall Eubanks


"Lucy E. Lynch" wrote:
>
> a bit more info on ramen here:
>
> http://members.home.net/dtmartin24/ramen_worm.txt
>
> "And now, the contents of that ramen.tgz file: All the binaries are in the
> archive twice, with RedHat 6.2 and RedHat 7.0 versions. Numerous binaries
> were not stripped, which makes the job of taking them apart easier."
>
> asp:       An xinetd config. file that will start up the fake webserver
>            Used on RedHat 7.0 victim machines.
> asp62:     HTTP/0.9-compatible server that always serves out the file
>            /tmp/ramen.tgz to any request - NOT stripped
> asp7:      RedHat 7-compiled version - NOT stripped
> bd62.sh:   Does the setup (installing wormserver, removing vulnerable
>            programs, adding ftp users) for RedHat 6.2
> bd7.sh:    Same for RedHat 7.0
> getip.sh:  Utility script to get the main external IP address
> hackl.sh:  Driver to read the .l file and pass addresses to lh.sh
> hackw.sh:  Driver to read the .w file and pass addresses to wh.sh
> index.html: HTML document text
> l62:       LPRng format string exploit program - NOT stripped
> l7:        Same but compiled for RedHat 7 - stripped
> lh.sh:     Driver script to execute the LPRng exploit with several
>            different options
> randb62:   Picks a random class-B subnet to scan on - NOT stripped
> randb7:    Same but compiled for RedHat 7 - NOT stripped
> s62:       statdx exploit - NOT stripped
> s7:        Same but compiled for RedHat 7 - stripped
> scan.sh:   get a classB network from randb and run synscan
> start.sh:  Replace any index.html with the one from the worm; run getip;
>            determine if we're RedHat 6.2 or 7.0 and run the appropriate
>            bd*.sh and start*.sh
> start62.sh: start (backgrounded) scan.sh, hackl.sh, and hackw.sh
> start7.sh:  Same as start62.sh
> synscan62:  Modified synscan tool - records to .w and .l files - stripped
> synscan7:   Same but compiled for RedHat 7 - stripped
> w62:        venglin wu-ftpd exploit - stripped
> w7:         Same but compiled for RedHat 7 - stripped
> wh.sh:     Driver script to call the "s" and "w" binaries against a given
>            target
> wu62:      Apparently only included by mistake.  "strings" shows it to be
>            very similar to w62; nowhere is this binary ever invoked.
>
> Lucy E. Lynch                           Academic User Services
> Computing Center                        University of Oregon
> [email protected]             (541) 346-1774
> Cell: (541) 912-7998                    [email protected]