`int setenv(const char *name, const char *value, int overwrite)`

> if overwrite is zero, then the value of name is not changed

flag is in $MSG and cow will say it if we don’t overwrite it :D

[read more](http://taqini.space/2020/04/19/UMDCTF-2020-Pwn-writeup/#Cowspeak-as-a-Service-250pt)

Original writeup (http://taqini.space/2020/04/19/UMDCTF-2020-Pwn-writeup/#Cowspeak-as-a-Service-250pt).