Manual for HIPS: Send message to other processes?

Your simple and clear explanations are highly appreciated to shed light on this subject. (Simple examples are also welcome)
What does it mean?
When does it happen?
Usually which kind of normal apps do it?
Symptoms of suspicious activities?
Any important remarks?

Your thoughts are also welcome at https://www.wilderssecurity.com/showthread.php?t=218867

Thanks in advance/xtree

 

The whole list of the tasks the messages can be used for is actually VERY VERY huge, so it is hardly can be put in short and in too clear way

Messages can be used to:
close another application
get text from other application windows
set test to other application windows
use DDE
simulate system shutdown
destroy another application window
simulate keyboard or mouse activity
simulate timer activity
IPC

every case needs separate review. For example, some vendors (like asus) use wm_ set/get text messages for IPC (their dll does it when it is injected in the processes). From the other side the same message can be used for malicious activity, for example using wm_settext it is possible to make IE to go to unwanted site.

 

Hi Alex s,

Thank you for your detailed explanation. So there are several cases when one can run into this pop-up.
What I experienced on my pc so far:
1. You can get this message when for instance net-related apps (email clients, security apps, software updates) try to reach the net thru a firewall.
2.When 'system explorer' type programs (Autoruns, Injecteddll) try to map the system.
3...?