[mosquitto-dev] logcheck warning about reduced log file size

[Dominik Reusser <domi_reusser@xxxxxxx>]

I just subscribed to the list - thank you very much for this excellent
MQTT implementation. It works very well.

I have run a mosquitto-broker for about half a year now, connecting with
various clients. Encryption of the communication is not possible since
some clients do not support this.

The system is set up on a Ubuntu 14.04 system, with mosquitto version 1.4.5.

Logfiles are checked with logcheck to detect irregularities.

Now I received the following warning:
*************** This could indicate tampering.
*** WARNING ***: Log file /var/log/mosquitto/mosquitto.log is smaller
than last time checked!

Now I'm wondering whether this may be caused by the logfile rotation
mechanism (rotation took place within the same period).

If this is plausible, why do I receive such a warning after half a year
for the first time?

If this is not plausible, how could I further track down what happened?

Does anyone have experience with this?

Also, what would be potential ways for gaining unauthorized access
through mosquitto? Is there a good summary about security and mosquitto?

Thanks for any comments in advance
Greetings
Dominik