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2017 juni examen

Theorie

  • 8 moeilijke doordenk multiple choice vragen (met meerdere mogelijke juiste antwoorden, en je moet ze allemaal juist hebben)
  • DNS query response gegeven van alle servers waarlangs de DNS query gaat. Leg uit met schema wat er gebeurt, wanneer wie welke responses geeft, welke queries iteratief/recursief zijn.
  • Waarom wordt er bij SSL/TCL zowel symmetrische als asymmetrische encryptie gebruikt? Leg uit met een schema van SSL en zeg waar welke gebruikt wordt (toy of echte SSL)

Praktijk

Praktijkexamen 22/05/2017

  • Give a list of all words with 14, 15 or 16 unique letters. The output format should look like this:
Words with 14 letters: word1 word2 word3
Words with 15 letters: word4 word5
...
for n in 14 15 16; do echo "Words with $n letters:" $(grep -P "^.{$n}$" dutch | grep -vP '(.).*\1'); done
tshark -r ftp_bruteforce.pcap -Y 'ftp.request.command == USER' -T fields -e ‘ftp.request.arg’ | sort -u
  • Give the current time (format: Time= hh:mm:ss (dd-mm-yyyy))
echo 'Time=' $(date +'%T (%x)') | tr / -
  • Write a oneliner to decode the following file "secret" (contents: RGUgcHVudGVuIG9wIGRlemUgdnJhYWcgemlqbiBhbCBiaW5uZW4uCg==)
The file ends with '==' indicating base64 padding: openssl enc -d -base64 < secret
  • Write a oneliner to display the fingerprint, serial and public key of wiki.uclllabs.be
echo | openssl s_client -connect wiki.uclllabs.be:443 2>/dev/null | openssl x509 -fingerprint -serial -pubkey -noout

Praktijkexamen 24/05/2017

  • There is a website running - https://darthvader.uclllabs.be/nw2/lab1 - which is only accessible from 193.191.177.1. That is the IP address of leia.uclllabs.be. Create an ssh tunnel between server leia and the webserver darthvader
ssh -L 10000:darthvader.uclllabs.be:443 user@leia.uclllabs.be -p 22345
  • Give a list of words with 5 letters that are also palindromes.
grep -P '^(.)(.).\2\1$' dutch
  • Show the file /etc/debconf.conf on screen without comment lines (i.e. lines starting with a #).
grep -vP '^#' /etc/debconf.conf
tshark -r ftp_bruteforce.pcap -Y 'ftp.request.command == USER' -T fields -e ‘ftp.request.arg’ | sort -u
  • Write a oneliner to display the fingerprint, serial and public key of wiki.uclllabs.be
echo | openssl s_client -connect wiki.uclllabs.be:443 2>/dev/null | openssl x509 -fingerprint -serial -pubkey
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