Modified packet sometimes not included in the topic
Hi, i have come across a weird issue while trying to experiment with packet crafting on a ROS2 network (basic install, not SROS2 with DDS).
For the setup i use one machine running ROS to simulate a Turtlebot3 and acting as publisher and another one running Gazebo as subscriber to replay the move of the Turtlebot in the simulation, then a Man In The Middle machine intercept the packet and edit them with ettercap filter to change the payload (like replacing a forward move with a forward+rotation). The result should be -> the turtlebot in the gazebo simulation acting differently from the original one, but it only does it sometime.
As for verification, i've used wireshark and tcpdump to confirm that only the modified packet reach the machine (and the original one don't) but when i echo the topic (cmd_vel) it seem that a 'fake' message is found in the topic only once every 10 to 20 messages. So for now instead of turning the straight line move into a curve, the turtlebot simply move forward and sometime rotate a bit.
Does someone know what could cause this behavior ? maybe a security in ROS communication i don't know of ?
Thank you.