TL;DR:

Given an SQLite database with encrypted messages and a memory dump of an Ubuntu VM.
Understand how the messages are generated by extracting the Python script that generated them from the memory dump, learn that they are AES encrypted with GCM mode. The script process is still running and the key is referenced by a global, so it can be extracted from the dump after parsing the `str` instances in the process memory. ~1400 of them are possible AES keys and can be all tried very quickly, getting the flag:

`CTF-BR{d3v14_73r_cr1p706r4f4d0_4n735_d3_ch364r_n4_cl0ud}`