Parse a substring out of string, allocate memory accordingly
A 0-ary function (swd_parseUsrPass) calling another 0-ary function (swd_getURLaddr) hints that there are global variables lurking around. Using globals is not recommended; if they are unavoidable, at least limit their visibility. Consider char swd_parseUsrPass(char * url_addr), and let the caller provide the argument.
sizeof(char) is guaranteed to be 1.
*(endIndx + 1) = '\0' modifies the source string, while usr_pass remains not terminated. I presume you meant

usr_pass[str_len] = '\0';