Category: Linux

Level: Medium

Type: Fix

Access: Public

Description: Your objective is to be able to insert a row in an existing Postgres database. The issue is not specific to Postgres and you don’t need to know details about it (although it may help).

Helpful Postgres information: it’s a service that listens to a port (:5432) and writes to disk in a data directory, the location of which is defined in the data_directory parameter of the configuration file /etc/postgresql/14/main/postgresql.conf. In our case Postgres is managed by systemd as a unit with name postgresql.

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Type: Do

Access: Email

Description: There’s a file /home/admin/scores.txt with two columns (imagine the first number is a counter and the second one is a test score for example).

Find the average (more precisely; the arithmetic mean: sum of numbers divided by how many numbers are there) of the numbers in the second column (find the average score).

Use exaclty two digits to the right of the decimal point. i. e., use exaclty two “decimal digits” without any rounding. Eg: if average = 21.349 , the solution is 21.34. If average = 33.1 , the solution is 33.10.

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Level: Easy

Type: Hack

Description: There is a web server on port :80 protected with Port Knocking. Find the one “knock” needed (sending a SYN to a single port, not a sequence) so you can curl localhost.

Test: Executing curl localhost returns a message with md5sum fe474f8e1c29e9f412ed3b726369ab65. (Note: the resulting md5sum includes the new line terminator: echo $(curl localhost))

La versión del Pelado Nerd la encontrás acá https://www.youtube.com/watch?v=45E_RChOfz0

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Level: Easy

Description: This is the Command Line Murders with a small twist as in the solution is different

Enter the name of the murderer in the file /home/admin/mysolution

Anteriormente intenté resolverlo sin éxito, te lo dejo acá para que lo veas
https://youtu.be/IM8A8nifWjg

Este es el segundo intento, ya con alguna idea de como encarar el desafío

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Level: Easy

Description: This is the Command Line Murders with a small twist as in the solution is different

Enter the name of the murderer in the file /home/admin/mysolution

Honestamente no sabía ni por donde arrancar, pero creo que nos quedaron algunos buenos indicios para un segundo intento

Recuerden que nadie nació sabiendo, lo importante es aprender en el camino 😊

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Level: Easy

Type: Do

Description: Alice the spy has hidden a secret number combination, find it using these instructions:

1) Find the number of lines with occurrences of the string Alice (case sensitive) in the *.txt files in the /home/admin directory
2) There’s a file where Alice appears exactly once. In that file, in the line after that “Alice” occurrence there’s a number.
Write both numbers consecutively as one (no new line or spaces) to the solution file.
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