Search This Blog

Tuesday, June 27, 2006

Wednesday, June 07, 2006

Index of /mtg-0606/pdf: Anna Claiborne's DDoS presentation in anna-claiborne.pdf

From Matthew Petach's NANOG posting ...

Information collection on DDoS attacks,
Anna Claiborne, Prolexic Technologies.
[slides are at:

DDoS mitigation service.
personal experience mitigating over 150 DDoS attacks.

Popular topic, but nobody talks about how you can defend yourself or take legal action; only thing you can do is collect information.

0.1% of DDoS attacks end in an arrest, that's out of the reported number to the US Secret Service, and that's out of the ones that fall into their jurisdiction.

These are real losses:
A major US corp lost over $2mil in a 20 hour outage An offshore gambling comp. lost estimated $4m in 3 days Online payment processor lost $400,000 in 72 hours online retailer lost $20K/day over 3 weeks.

These are directly reported losses; doesn't include lost PR, etc.

Canadian retailer spend 50K on hardware mitigation, they got kicked out of 3 datacenters due to the DDoS attacks, spent 20K on IT and security consultants, and another $6K on a different mitigation that also failed.

Basic Information Collection
Get packet captures--either from machine being attacked, or a span port, or from upstream device, tcpdump -n -s0 -C (get full length of raw packet, limit pcap file to 5MB or smaller) take 3 or 4 over 15 minutes, to start, and then repeat every hour Determine the type of attack and duration (ex SYN flood lasting 6 hours) Obtain as complete a list as possible of source IP addresses Save bandwidth graphs, flow data, pps graphs, any and all visual material relating to the attack Save any contact with the attacker, email, chat conversation, phone calls, etc.
Get loss figures from management--downtime, per hour losses, per day losses, section 18 of some law, have to substantiate losses over $5k before you can take legal action against someone.

have a plan! DDoS is stressful
Put all attack information in a central location God monitoring doesn't have to be expensive, a simple fiber card in a 1u box can be a mirror port for a large volume of traffic Don't have to have expensive hardware like arbor
Limit to 100mb to prevent killing your capture box.
Graphs and flow data can be retrieved from upstream

Find the source
Use list of source addresses, find a reputable hosting company, you may even see a friend's IP Approach the network with the infected machine, give them as much information as possible, it can take time finding someone willing to help Obtaining information is dependent on who you are dealing with, be as helpful as possible.
Get information from the infected machine netstat, tcpdumps, who is logged in, web logs, access logs Get and save the source code responsible

process can take hours to weeks--prolexic has huge contact list, and even for them can be really difficult And SAVE all your information to a central location!
and back it up!

Examine the source code
scripts are best, you know exactly what's going on compiled code, run strings on it best case, you can get a name or identification for who wrote it, passwords, domain names, port usage worst case you can obtain information that doesn't make sense...yet (it may fit into a bigger context later)

Locate controlling server
Examine TCP connection table or source code to find the controlling server verify your information, scan or connect to the suspect machine contact abuse where the server is hosted, explain the situation have as much information possible to verify your conclusion and validate your identity Good luck, most abuse contacts are less than helpful Raises a good question: how to improve awareness and legitimate requests answered.
(may be able to get FBI to provide warrants to seize machines that are being used to control attacks against you, but takes time and documentation)

Hunting the attacker (not for the faint of heart!) Review all information gathered so far on the attack contact the attacker, establish a report save all information and/or conversations (important note, if conversations aren't on a public server, they can't be used) Piecing the information together to form a high level view of the exploit, attack, and attacker A long process, most attackers are highly motivated and skilled, you usuallly have to wait for them to slip up!

local FBI field office department of cybercrime department of homeland security CERT Cymru--great guys, if they have to help you NHTCU--EU, cyber crime divisions in local offices Local US secret service--division of electronic crimes -- under development at the moment.
how to identify/recognize different types of attacks
may be able to put their attack database open to the
public up there.

A success story
The tracking of x3m1st/eXe
responsible for hundreds of extortion based DDoS attacks tracked for months eventually lead to his arrest.

hid behind four levels of compromised servers.

eXe and his group only talked on private IRC servers; made the mistake of connecting from his home domain, from a machine registered to his real name; that was his slip up, Ivan arrested in Russia.

Tracking Pkeglhema/aaabaa
targetted redhat linux boxes for his zombies they generally sat on higher bandwidth links.
PHP/cross scripting vulnerability; insert the script without validity checking.
Used cpanel holes, mySQL holes, he browsed zeroday, modified code in a few hours to use new holes,

The result: synflood over 10G, knocked upstreams off, and got them null routed, bunch of outbound networks also null routed.

some conversations recorded, he was paid by an employer, he'd done this before for other employers.

He eventually got away.
English as a second language, always from hacked university, attacking six other sites that also sold similar items as the client under protection.
They'd had phone calls from competitors trying to push them out of business, and was during the busiest time of year for them.

He was most professional attacker she's dealt with, he never slipped up, he'd been doing this for years.
Logged in from China or Japan.

She turned over info to FBI, let them pursue things further.

Matters to address in community
Better abuse contacts, specific to DDoS
Centralized repository specifically for DDoS profiling Information gathering is extremely resource intensive, but worth it.
Null routing IP space is not a good idea from either side DDDoS is everyone's problem.

fix your open recursive DNS servers!!

NHTCU--Mike Hughes, rolled into SOCA, serious organized crimes something--DDoS is way down on the list, they're more into big crimes. Watch for more developments in that space though.
NHTCU was more approachable,

Q: Bill Woodcock--could she talk more about public vs private IRC servers---what is the legal issue?
A: private IRC server is any run that is not publically accessible, is only open to the group.
Any machine that is hacked is a private IRC server, since it is not intended for public access.
public--a machine run so that anyone can connect to it, and intended as such.
You can assert the conversation, but it is hearsay; it can help in court, but it is itself not admissable as evidence.

Q: Tony Kapella, 5nines--what does Prolexic suggest customers do to make sure their host hasn't been compromised to the point where netstat and other utilities are affected?
A: Well, you have to trust the people you work with to be able to verify that the information they're seeing is accurate. But for boxes that neither side has access to, like colocation boxes, you could just be out of luck.

Q: Gene Kim? what if the server is located outside the US?
A: fine as long as it's publically accessible.
Q: What about private messages?
A: fine as long as it's a public IRC server

Q: Louis Lee, equinix--suggest mirror switch port to address Tony's issue; capture unaffected traffic to a virgin machine when possible.

Q: Rob seastrom, bluetrust--what is the incidence of encrypted communication, and multiple C&C hosts?
A: This only works for easiest case scenario of non-spoofed attack with centralized C&C attack.
Peer to peer, proxy servers, etc. you need to go to an expert.

Q: Stuart Phillips, New Metra...he's cut off...raise it at the security BOF.

Announcements--if you've not picked up your shirt, pick it up, JD Frazer, userfriendly did the image.

A few short of goal of six for lightning talks; sign up, or we'll have Randy sing at you.

PGP signing during this break too.

Be back at 10 after.