# 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](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](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 ```