**tl;dr**

+ The dump has some encrypted functions
+ The encrypted bytes are being xorred with a 32 byte key
+ Find the xor_key in the dump
+ Use xor_key offset to find(Bruteforce) the offset of AES_key and iv
+ AES_CBC decrypt to find flag

Original writeup (https://blog.bi0s.in/2021/02/28/RE/Linux/AeroCTF21-dummyper/).