/etc/cron.daily/exim4-base swears. What could be and how to fix it?

Question

linux

OS: Debian 8
Error:

/etc/cron.daily/exim4-base:
LOG: MAIN
  Warning: purging the environment.
 Suggested action: use keep_environment.
/etc/cron.daily/logrotate:
error: skipping "/var/log/iptraf/ip_traffic-1.log" because parent directory has insecure permissions (It's world writable or writable by group which is not "root") Set "su" directive in config file to tell logrotate which user/group should be used for rotation.
error: error running shared postrotate script for '/var/log/mysql.log /var/log/mysql/mysql.log /var/log/mysql/mysql-slow.log /var/log/mysql/error.log '
run-parts: /etc/cron.daily/logrotate exited with return code 1

Answer 1

because parent directory has insecure permissions (It's world writable or writable by group which is not "root")
says that other groups can write to this directory, you need to edit the permissions.
Can I see the output of the command?
ls -l /var/log/ | grep iptraf
ls -l /var/log/iptraf