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 

 

 Give a list of the usernames tried in ftp_bruteforce.pcap. You can only use tshark and sort (Step by step solution:  https://wiki.uclllabs.be/index.php/TShark_Tutorial#Exercises ) 

 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 

 

 Give a list of the usernames tried in ftp_bruteforce.pcap. You can only use tshark and sort (Step by step solution:  https://wiki.uclllabs.be/index.php/TShark_Tutorial#Exercises ) 

 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