They tend to use average metering for their auto exposure, where they set their exposure based on the average brightness of the entire scene. This is made worse by the lack of spot or zone metering in these security cameras. Anything too bright will be 'blown out', and anything too dark will be lost in the noise.
And when you set the exposure, you are selecting which slice you want to capture. I always point out that any camera system can only capture a 'slice' of the scene's dynamic range. There is always a limit to the dynamic range (the range of brightnesses) that can be captured. People forget that security camera use is exactly like any other photography.