Ssl

plaidCTF 2014 - freya (misc250)

For PlaidCTF2014, Eindbazen and fail0verflow joined forces as 0xffa, the Final Fail Alliance.
Don't miss out on other write-ups at Eindbazen's site!

This challenge is part of the misc category:

freya
Misc (200 pts)
-------------------
We've traveled back far, but this protocol looks familiar...
Our reconnaissance team did a great job, they got us a data capture
from the currently running systems and a private key
from the server (shell.woo.pctf which resolves to 54.226.73.167).
Take  a look at the traffic our reconnaissance team picked up, and see if you
can get access to The Plague's server, at 54.226.73.167.

with the following four files:

  • freya.pcapng
  • freya_cert.pem
  • freya_priv.pem
  • password

The task is pretty simple - somehow get access to shell.woo.pctf, probably by using ssh.

plaidCTF 2014 - curlcore (for250)

For PlaidCTF2014, Eindbazen and fail0verflow joined forces as 0xffa, the Final Fail Alliance.
Don't miss out on other write-ups at Eindbazen's site!

Last week we played plaidCTF with Eindbazen under the name 0xffa (can you figure out why that name?). Write-ups are mandatory in the rules, so let’s start with an easy one :-)

curlcore
Forensics (250 pts)
-------------------
We managed to grab a memory dump off of The Plague's computer while
he was making a secure download. We think he may have been looking
for new places to hide the Prime Factorizer. Can you figure out what
messages were sent through his computer?

For this challenge, you get 3 files:

  • capture (a network capture)
  • corefile (a memory dump)
  • coremaps (the process’s memory map)

and the shell script which helped generating those files

:::bash
#/bin/sh

sudo rm /tmp/capture 2>/dev/null
sudo dumpcap -i eth0 -w /tmp/capture &
DUMPCAPPID=$!

sleep 1
OUTPUT="`/usr/bin/env -i /bin/dash -c 'ulimit -c unlimited; curl -k https://curlcore.local.plaidctf.com/flag.html & PID=$!;     sleep 5; printf "generate-core-file\ninfo proc mappings\ndetach\n" | sudo gdb attach $PID; wait'`"
sleep 1

sudo kill -INT $DUMPCAPPID
wait

sudo chown `whoami` /tmp/capture

echo "$OUTPUT"

sudo mv "`echo "$OUTPUT" | grep -o 'Saved corefile .*$' | cut -c 16-`" /tmp/corefile
sudo chown `whoami` /tmp/corefile


echo "$OUTPUT" | awk '/Mapped address spaces/,/(gdb)/' | grep -v '(gdb)' > /tmp/coremaps

rm /tmp/curlcore.tgz 2>/dev/null
tar czf /tmp/curlcore.tgz `grep -o ' /.*$' /tmp/coremaps | sort -us | tr '\n' ' '` /tmp/corefile /tmp/coremaps /tmp/capture     "$0"

Since we have a network capture of the https download, we need to find a way to decrypt the SSL communication…