I do not recommend adding every IP listed at DShield to your filter. We do publish a 'block list', of the worst networks (based on reports for the last 5 days). Quick note on our methods: We basically aggregate firewall logs and offer summarized reports. The reports should allow everyone to apply their own judgment. For the block list: http://www.dshield.org/block_list_info.html On Sat, 27 Jul 2002 20:19:47 -0400 "Phil Rosenthal" <pr@isprime.com> wrote:

I can comment on the dshield list. I have seen this before. I am checking one particular IP on my network that has a very popular freehost on it. Checking the load balancer IP (connections cannot be originated from this IP) -- it shows that there were 13 attacks initiated from the IP, and 7 targets. Whatever their algorithm is, it doesn't seem reliable enough for me to trust it if an IP that can not originate connections is listed as an attacker (albeit small on their list) --Phil

-----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of alsato Sent: Saturday, July 27, 2002 8:08 PM To: nanog@merit.edu Subject: Bogon list or Dshield.org type list

Im wondering how many of you use Bogon Lists and http://www.dshield.org/top10.html type lists on your routers? Im curious to know if you are an ISP with customers or backbone provider or someone else? I have a feeling not many people use these on routers? Im wondering why or why not? Ive never used them on my routers although I work for a new isp/cable provider. Im thinking it would make my users happy to use them though.

alsato

-- --------------------------------------------------------------- jullrich@sans.org Collaborative Intrusion Detection join http://www.dshield.org

Yes - DSHEILD has our ORSC root server listed as well. I thought that was hilarious. ----- Original Message ----- From: "Charles Sprickman" <spork@inch.com> To: "Johannes Ullrich" <jullrich@sans.org> Cc: <nanog@merit.edu> Sent: Sunday, July 28, 2002 2:36 AM Subject: Re: Bogon list or Dshield.org type list

I looked up a nameserver that I once worked with and found that it is "attacking" from port 53. Needless to say, it's not hacked, it's answering queries.

Charles

-- Charles Sprickman spork@inch.com

On Sat, 27 Jul 2002, Johannes Ullrich wrote:

...

I do not recommend adding every IP listed at DShield to your filter. We do publish a 'block list', of the worst networks (based on reports for the last 5 days).

Quick note on our methods: We basically aggregate firewall logs and offer summarized reports. The reports should allow everyone to apply their own judgment.

For the block list: http://www.dshield.org/block_list_info.html

On Sat, 27 Jul 2002 20:19:47 -0400 "Phil Rosenthal" <pr@isprime.com> wrote:

...

I can comment on the dshield list. I have seen this before. I am checking one particular IP on my network that has a very popular freehost on it. Checking the load balancer IP (connections cannot be originated from this IP) -- it shows that there were 13 attacks initiated from the IP, and 7 targets. Whatever their algorithm is, it doesn't seem reliable enough for me to trust it if an IP that can not originate connections is listed as an attacker (albeit small on their list) --Phil

-----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of alsato Sent: Saturday, July 27, 2002 8:08 PM To: nanog@merit.edu Subject: Bogon list or Dshield.org type list

Im wondering how many of you use Bogon Lists and http://www.dshield.org/top10.html type lists on your routers? Im curious to know if you are an ISP with customers or backbone provider or someone else? I have a feeling not many people use these on routers? Im wondering why or why not? Ive never used them on my routers although I work for a new isp/cable provider. Im thinking it would make my users happy to use them though.

alsato

-- --------------------------------------------------------------- jullrich@sans.org Collaborative Intrusion Detection join http://www.dshield.org

I can comment on the dshield list. I have seen this before. I am checking one particular IP on my network that has a very popular freehost on it. Checking the load balancer IP (connections cannot be originated from this IP) -- it shows that there were 13 attacks initiated from the IP, and 7 targets. Whatever their algorithm is, it doesn't seem reliable enough for me to trust it if an IP that can not originate connections is listed as an attacker (albeit small on their list) --Phil

-----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of alsato Sent: Saturday, July 27, 2002 8:08 PM To: nanog@merit.edu Subject: Bogon list or Dshield.org type list

Im wondering how many of you use Bogon Lists and http://www.dshield.org/top10.html type lists on your routers? Im curious to know if you are an ISP with customers or backbone provider or someone else? I have a feeling not many people use these on routers? Im wondering why or why not? Ive never used them on my routers although I work for a new isp/cable provider. Im thinking it would make my users happy to use them

"I do not recommend adding every IP listed at DShield to your filter" /understatement. I took a short while to peruse the data collected and distributed by DShield. I don't believe I need to go into the many reasons (I'm sure you know yourself) why this information is completely unreliable, but worse, possibly damaging. Offering this data, backed up by SANS name for credibility, might entice a novice engineer to act upon it. This: "Disclaimer DShield currently employs as little filtering of incoming reports as possible. Most reports are sent anonymously. We do not know if these logs are truthful, or if the firewall configuration was correct. DShield.org will attempt to protect the identity of the submitter. If you have a question regarding a specific target or source IP, please send an e-mail to info@dshield.org." is insufficient and-IMHO-irresponsible. That said, I do believe your motives and purpose is worthwhile, but the process completely undermines them both. If you're interested in retooling the scripts and using registered and credible sources, I would not only offer assistance in the effort but endorse it as well. Jeff Nelson PGP: 0x54B1A25C "There are 10 types of people: those that understand binary, and those that do not. -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Johannes Ullrich Sent: Saturday, July 27, 2002 9:49 PM To: pr@isprime.com Cc: alsato@hotpop.com; nanog@merit.edu Subject: Re: Bogon list or Dshield.org type list I do not recommend adding every IP listed at DShield to your filter. We do publish a 'block list', of the worst networks (based on reports for the last 5 days). Quick note on our methods: We basically aggregate firewall logs and offer summarized reports. The reports should allow everyone to apply their own judgment. For the block list: http://www.dshield.org/block_list_info.html On Sat, 27 Jul 2002 20:19:47 -0400 "Phil Rosenthal" <pr@isprime.com> wrote: though.

alsato

-- --------------------------------------------------------------- jullrich@sans.org Collaborative Intrusion Detection join http://www.dshield.org

"/overstatement" -- fair enough. I don't mean to diminish the effort. I guess it is the unused potential that gets under my skin here. This could actually be an extremely useful tool for research if the data had some sense of accountability. "one has to understand and take into account how it is collected" Based on your methods of collection, with minimal work, one could make 167.216.198.40 #1 on Most Wanted list (assuming sans.org is not on the false positive's list). Anyway, that's my $.02... I'll mind my own business now GL, j -----Original Message----- From: Johannes Ullrich [mailto:jullrich@sans.org] Sent: Sunday, July 28, 2002 4:24 PM To: jnull Cc: nanog@merit.edu; info@dshield.org; info@sans.org Subject: Re: Dshield.org

"I do not recommend adding every IP listed at DShield to your filter" /understatement.

I took a short while to peruse the data collected and distributed by DShield. I don't believe I need to go into the many reasons (I'm sure you know yourself) why this information is completely unreliable, but worse, possibly damaging.

/overstatement ;-) DShield data is not 'completely unreliable'. However, in order to use it, one has to understand and take into account how it is collected. If you find one of your machines listed as 'attackers', you may want to take a closer look at the reports. If it turns out that the machine in question is your DNS server, and the reports listed are port 53 requests, you can probably assume that everything is fine, in particular if there are only a few reports. We (DShield) don't apply any filters, but this doesn't indicate that you shouldn't. We do no apply any filters because we do not know your network configuration. In several cases, we added IPs to our 'false positive' list of IPs which we consider as common sources of false positive reports. For example, root DNS servers are on this list, some large load balancers and some port scan sites (Shields Up...) -- --------------------------------------------------------------- jullrich@sans.org Collaborative Intrusion Detection join http://www.dshield.org