CategoryPuzzle #4

Puzzle #4 Winners

Here it is, finally, the announcement of the Puzzle #4 winner, finalists, and semifinalists. Once again, a huge congratulations to everyone who sent in correct answers to what was arguably our most difficult contest yet!

And as we’re sort of beginning to expect, we were totally blown away by the quality of the analysis we received. While there were lots of correct guesses at the “X-tra Credit”, many of you found solid ways to demonstrate (with references and citations) your passive fingerprinting of the active fingerprinting tool. Nice.

I’ll be following up with commentary and emails to a few of you and answering previous posts and the like, over the next few days. In the meantime, please do check out the Finalist submissions, particularly that of our winner… (drum roll)…

Sébastien Damaye has seriously thrown down the gauntlet on this one, and deserves an uncontested First Prize. (We’ve already begun to use his tools to look at other pcaps.)

At the core of the solution to this puzzle, and so many other similar real-world puzzles, is the ability to look at stochastic data, and do a sufficiently deep (and sometimes fuzzy) statistical analysis to determine what was going on. Lots of you made impressive inroads on how to shake out that analysis, but Sébastien gave us a new tool to bring things like sequence and acknowledgement number distributions stark view. Rather than go on to describe his efforts further myself, I’ll direct you to his own impressive write-up at aldeid.com.

Congratulations, Sébastien! Your shiny new netbook is on it’s way soon!

Of course there are several other submissions we want to mention (in order of submission):

As a few other folks did, Eugenio Delfa began an excellent first pass with snort to look for malfeasance, and to identify the port scanner. His new python script looks useful as well, allowing command-line statistical inspection without all the awk’ing and sorting I typically do with tcpdump or tshark output.

Eric Kollmann starts right off with a correct identification of nmap based on its known behavior, including the predictable things it does with SYN packets, and its use of a bogus ICMP code in the OS fingerprinting tests. His development of a new exe (“nfc”), and tweaks to Satori are welcome additions to his ongoing contributions to the community.

Arvind Doraiswamy submitted a perl script to extract and summarize flow data as well, and Adam Bray‘s pkts2db.pl & scansearcher.pl are solid contributions.

Thanks again to everyone who participated, and more than that, hold on to your hats. Puzzle #5 is imminent, and looks like a lot of fun!


Winner:

Sébastien Damaye (wins a Lenovo Netbook)

Finalists:

Adam Bray
Arvind Doraiswamy
Eric Kollmann
Eugenio Delfa

Semifinalists:

Ahmed Adel Mohamed
Christian
Garima
Jason Kendall
Juan Garrido & Pedro Sanchez
Peter Chong
Sterling Thomas
Tom Samstag
Vikrant

Correct:

Adam Bray
Ahmed Adel Mohamed
Anand Harikrishnan
Arvind Doraiswamy
Chad Stewart
Chris Steenkamp
Christian
David Clements
Eric Kollmann
Eugenio Delfa
Francisco Pecorella
Garima
Gustavo Delgado
Jason Kendall
Juan Garrido & Pedro Sanchez
Marco Castro
Masashi Fujiwara
Matt McKnew
Peter Chong
Sébastien Damaye (wins a Lenovo Netbook)
Sterling Thomas
Takuro Uetori
Tom Samstag
Vikrant
Winter Faulk

Puzzle #4 Answers

Here are the answers to Puzzle #4. Another big thanks to everyone who played. 🙂

Answer 1: 10.42.42.253
Answer 2: TCP Connect
Answer 3: 10.42.42.50, 10.42.42.56, & 10.42.42.25
Answer 4: 00:16:cb:92:6e:dc
Answer 5: 10.42.42.50
Answer 6: 135, 139

X-TRA CREDIT: The tool used was nmap. There are many ways to try to fingerprint the tool, but one fast way is to look at the TCP window sizes coming from the scanning system. In the case of nmap, some things stand out, including SYN packets with a window size of 31337. A google search on that turns up Fyodor’s patent application. 🙂

The first scan, run with “nmap 10.42.42.1/24” would have yielded results that looked something like this:

Starting Nmap 4.76 ( http://nmap.org ) at 2009-11-02 18:33 EST
All 1000 scanned ports on 10.42.42.25 are closed

Interesting ports on 10.42.42.50:
Not shown: 998 closed ports
PORT STATE SERVICE
135/tcp open msrpc
139/tcp open netbios-ssn

All 1000 scanned ports on 10.42.42.56 are closed

Interesting ports on 10.42.42.253:
Not shown: 999 closed ports
PORT STATE SERVICE
3128/tcp open squid-http

Nmap done: 256 IP addresses (4 hosts up) scanned in 468.46 seconds

(Though of course you couldn’t have known about 10.42.42.253, which was the scanner itself, as it would have used the loopback interface for that, and so the external packet sniffer wouldn’t have seen those bits.)

The second scan, using nmap’s “-A” option would have yielded results like this:

Starting Nmap 4.76 ( http://nmap.org ) at 2009-11-02 18:42 EST
All 1000 scanned ports on 10.42.42.25 are closed
MAC Address: 00:16:CB:92:6E:DC (Apple Computer)
Device type: phone|media device|general purpose|web proxy|specialized
Running: Apple embedded, Apple iPhone OS 1.X, Apple Mac OS X 10.2.X|10.3.X|10.4.X|10.5.X, Blue Coat SGOS 5.X, FreeBSD 4.X, VMware ESX Server 3.0.X
Too many fingerprints match this host to give specific OS details
Network Distance: 1 hop

Interesting ports on 10.42.42.50:
Not shown: 998 closed ports
PORT STATE SERVICE VERSION
135/tcp open msrpc Microsoft Windows RPC
139/tcp open netbios-ssn
MAC Address: 70:5A:B6:51:D7:B2 (Unknown)
Device type: general purpose
Running: Microsoft Windows XP
OS details: Microsoft Windows 2000 SP4, Windows XP SP2 or SP3, or Windows Server 2003
Network Distance: 1 hop
Service Info: OS: Windows

All 1000 scanned ports on 10.42.42.56 are closed
MAC Address: 00:26:22:CB:1E:79 (Unknown)
Too many fingerprints match this host to give specific OS details
Network Distance: 1 hop

Interesting ports on 10.42.42.253:
Not shown: 999 closed ports
PORT STATE SERVICE VERSION
3128/tcp open http-proxy Squid webproxy 2.7.STABLE3
Device type: general purpose
Running: Linux 2.6.X
OS details: Linux 2.6.17 – 2.6.25
Network Distance: 0 hops

OS and Service detection performed. Please report any incorrect results at http://nmap.org/submit/ .
Nmap done: 256 IP addresses (4 hosts up) scanned in 78.42 seconds

(Again, you wouldn’t have seen nmap inspect the host it was running on, but the results are included for completeness.)

Puzzle #4 Update

After reviewing the submissions so far, it seems that question #2 is perhaps a little too ambiguous. We’re amending it to read:

For the FIRST port scan that MR. X conducted, what type was it?

If you’ve already posted a submission, please re-evaluate your answer accordingly, and feel free to re-submit!

Also, we’ll be extending the deadline by two weeks to 3/18/10.

Cheers!

Contest #4 Prize Announcement

After much deliberation, we’ve decided to again offer a Lenovo IdeaPad S10-2 to the winner of Contest #4.

As mentioned before, this model is the same as the free netbooks Sec558 students will get in Orlando!

The MOST ELEGANT solution wins. Deadline is 03/04/10. Good luck!!

Puzzle #4: The Curious Mr. X

While a fugitive in Mexico, Mr. X remotely infiltrates the Arctic Nuclear Fusion Research Facility’s (ANFRF) lab subnet over the Interwebs. Virtually inside the facility (pivoting through a compromised system), he conducts some noisy network reconnaissance. Sadly, Mr. X is not yet very stealthy.

Unfortunately for Mr. X, the lab’s network is instrumented to capture all traffic (with full content). His activities are discovered and analyzed… by you!

Here is the packet capture containing Mr. X’s activity. As the network forensic investigator, your mission is to answer the following questions:

1. What was the IP address of Mr. X’s scanner?
2. For the FIRST port scan that Mr. X conducted, what type of port scan was it? (Note: the scan consisted of many thousands of packets.) Pick one:

  • TCP SYN
  • TCP ACK
  • UDP
  • TCP Connect
  • TCP XMAS
  • TCP RST

3. What were the IP addresses of the targets Mr. X discovered?
4. What was the MAC address of the Apple system he found?
5. What was the IP address of the Windows system he found?
6. What TCP ports were open on the Windows system? (Please list the decimal numbers from lowest to highest.)
X-TRA CREDIT (You don’t have to answer this, but you get super bonus points if you do): What was the name of the tool Mr. X used to port scan? How can you tell? Can you reconstruct the output from the tool, roughly the way Mr. X would have seen it?

Deadline is 3/18/10 (11:59:59PM UTC-11) (In other words, if it’s still 3/18/10 anywhere in the world, you can submit your entry.)

Please use the Official Submission form to submit your answers. Here is your evidence file:
http://forensicscontest.com/contest04/evidence04.pcap
MD5 (evidence04.pcap) = 804648497410b18d9a7cb1d4b2252ef7

The MOST ELEGANT solution wins. In the event of a tie, the entry submitted first will receive the prize. Coding is always encouraged. We love to see well-written, easy-to-use tools which automate even small sections of the evidence recovery. Graphical and command-line tools are all eligible. You are welcome to build upon the work of others, as long as their work has been released under a an approved Open Source License. All responses should be submitted as plain text. Microsoft Word documents, PDFs, etc will NOT be reviewed.

Feel free to collaborate with other people and discuss ideas back and forth. You can even submit as a team (there will be only one prize). However, please do not publish the answers before the deadline, or you (and your team) will be automatically disqualified. Also, please understand that the contest materials are copyrighted and that we’re offering them publicly for the community to enjoy. You are welcome to publish full solutions after the deadline, but please use proper attributions and link back. If you are interested in using the contest materials for other purposes, just ask first.

Exceptional solutions may be incorporated into the SANS Network Forensics Investigative Toolkit (SNIFT kit). Authors agree that their code submissions will be freely published under the GPL license, in order to further the state of network forensics knowledge. Exceptional submissions may also be used as examples and tools in the Network Forensics course. All authors will receive full credit for their work.

Deadline is 3/18/10 (11:59:59PM UTC-11). Here’s the Official Submission form. Good luck!!

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