Hi,
I noticed some weird beahivour with periodically someone sending 1 character to the chat I have on a website.
Didn't notice anything in the logs, but found that a new logfile had popped into /var/logs: 20221103_exception.log
This is weird because I have never seen logfile like this in that directory.
It started like this:
*ERROR* v1.7.8.7 2022/11/03 - 00:43:39: Link to database cannot be established: SQLSTATE[HY000] [2006] MySQL server has gone away at line 136 in file classes/db/DbPDO.php *ERROR* v1.7.8.7 2022/11/03 - 00:43:39: Link to database cannot be established: SQLSTATE[HY000] [2006] MySQL server has gone away at line 136 in file classes/db/DbPDO.php *ERROR* v1.7.8.7 2022/11/03 - 00:43:39: Link to database cannot be established: SQLSTATE[HY000] [2006] MySQL server has gone away at line 136 in file classes/db/DbPDO.php *ERROR* v1.7.8.7 2022/11/03 - 00:43:39: Link to database cannot be established: SQLSTATE[HY000] [2002] Connection refused at line 136 in file classes/db/DbPDO.php *ERROR* v1.7.8.7 2022/11/03 - 00:43:39: Link to database cannot be established: SQLSTATE[HY000] [2002] Connection refused at line 136 in file classes/db/DbPDO.php *ERROR* v1.7.8.7 2022/11/03 - 00:43:39: Link to database cannot be established: SQLSTATE[HY000] [2002] Connection refused at line 136 in file classes/db/DbPDO.php *ERROR* v1.7.8.7 2022/11/03 - 00:43:41: Link to database cannot be established: SQLSTATE[HY000] [2002] Connection refused at line 136 in file classes/db/DbPDO.php
And then continues like this with a new line every few minutes or so:
*ERROR* v1.7.8.7 2022/11/03 - 03:59:46: Can not retrieve the id_product_attribute at line 7532 in file classes/Product.php *ERROR* v1.7.8.7 2022/11/03 - 03:59:50: Can not retrieve the id_product_attribute at line 7532 in file classes/Product.php *ERROR* v1.7.8.7 2022/11/03 - 03:59:57: Can not retrieve the id_product_attribute at line 7532 in file classes/Product.php *ERROR* v1.7.8.7 2022/11/03 - 04:00:20: Can not retrieve the id_product_attribute at line 7532 in file classes/Product.php *ERROR* v1.7.8.7 2022/11/03 - 04:00:20: Can not retrieve the id_product_attribute at line 7532 in file classes/Product.php
No changes has been done to the classes/Product.php
Acces logs show this. And I think this answers the question, because I was not able to post this as text and got firewalled 
Does seem like SQL injection attempt??
Any idea where to look next? Or what is being possibly attempted here?