Testing Commonly Suggested Thermal Bypassing Items

Thermal sensors, such as Passive Infrared (PIR) sensors and thermal-detecting cameras, play a significant role in modern security systems. These devices detect heat signatures and movement, making them a critical line of defense for many facilities. But what if you wanted to understand how to bypass them—whether for legitimate testing or educational purposes?

There are many theories about what works and what doesn’t when attempting to bypass thermal sensors. I get lots of questions and suggestion on what may or may not work, so this blog post dives into several popular methods, presenting video demonstrations of their effectiveness and analyzing the factors that influence success or failure.

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Common Ideas for Bypassing Thermal Sensors

Here, we’ll explore six common strategies people suggest for bypassing thermal sensors:

1. Wearing heavy jackets or clothing

2. Using a survival blanket

3. Using thermal insulation

4. Using a wool blanket

5. Using an umbrella

6. Combining multiple methods

Each method will be tested and demonstrated in a controlled environment to assess its effectiveness.

These were tested in narrow hallways, large rooms and outdoors as these are likely the most common areas a black team will encounter these sensors. From left to right: narrow hallway, large room & outside.

For these tests, there are a few characteristics that are critical for grading their effectiveness:

• How bulky & heavy is it - very heavy or bulky items will make covert entry more challenging

• How effective is it at preventing detection - roughly speaking, how good is the item at actually hiding you

• Side effects - Are there any positive or negative side effects of using the item in regards to the sensor

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Factors Affecting the Success of Thermal Bypasses

Before diving into the results, it’s important to understand that several environmental and physical factors significantly influence the success of any bypassing method:

• Background temperature: If the ambient temperature closely matches your body temperature, you’ll naturally blend in better. Conversely, a significant difference in temperature will make you more noticeable.

• Room or hallway dimensions: Narrow spaces can reflect heat off walls, making you detectable from multiple angles.

• Heat Sources: Even if you have a perfect bypass item, if you walk in front of a heat or cold source, you just drastically changed what the sensor was expecting

• Contact with the blocking material: If your body is in direct contact with the material (like holding a wool blanket), your heat can seep through, revealing your position.

• Wind conditions: Materials like survival blankets or thermal insulation are vulnerable to movement in windy conditions, which can momentarily expose parts of your body.

• Proximity to the sensor: The closer you are to the sensor, the more likely it is to detect even small heat leaks or reflections.

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Baseline

In the video below, you will see what a person looks like without any insulation or attempting to bypass the sensor. This demonstration is performed in a narrow hallway, and you can see how the thermal radiation bounces off the walls, making me visible not just from the front, but from the sides as well, something you will need to consider.