Silence Means Security? Basics of OpSec for the Layperson


Operational Security (OpSec) is the process of preventing useful information from being gained by an adversary.

OpSec is not simply a set of actions you take during an action that protects you. It’s a way of thinking you apply to all aspects of your life. OpSec is also not an individual undertaking. Your personal security depends on the security of your comrades and vice versa. This is often called “security culture.”

The definition of OpSec is more formalized in the contexts of military and espionage, and in those cases it tends to have the explicit focus on only protecting information. In colloquial usage, it tends to be broader and includes the adjacent fields of information security and physical security. This is a natural extension of the original definition since a significant amount of secret information is transmitted digitally, and a breach of OpSec may have immediate physical security ramifications.

Threat Modeling

Threat modeling is the foundation of OpSec. It’s a methodology used to identify threats, and through this identification, inform mitigations against them. Threat modeling is not a checklist that someone can give you to reduce your risks or ensure your adversaries cannot achieve their goals. Threat modeling must be done analytically on a case-by-case basis. The process of developing an individual threat model is similar regardless of the person doing the threat modeling, but the resultant threat model is highly personalized.

OpSec Vocab

target
a person or group who may be subject to scrutiny, repression, or espionage
asset
something a target may want to protect such as information, physical items, or intangibles like their own liberty, mental health, or bodily health
adversary
a person or group who wants to learn about, capture, or destroy a target’s assets
goal
a specific task or outcome an adversary wishes to achieve
capability
knowledge, a skill, or an item an adversary has that may use against a target to achieve goals
vulnerability
something an advesary could exploit or leverage in pursuit of their goals
threat
the combination of an adversary with their goals and capabilities
attack
a possible threat that is executed
mitigation
an action taken to reduce risk

You are likely familiar with threat modeling and have already used it in your day-to-day life even if you have not done so formally. Making this decision to keep your phone in your pocket and not message your comrades while you walk home at night is threat modeling. You have recognized that the threat of mugging or assault exists in a certain area, that this risk is higher at night, and that you are less likely to be targeted if you are visibly paying attention to your surroundings.

Your threat model will need to change with time as the threat landscape and your own tolerance for risk changes. The political climate may become more repressive, or you may start a family and need to reconsider what possible consequences you and your family can endure.

To start building your threat model, start by identifying your assets, possible adversaries, their goals, and their capabilities. Helpful questions might be:

  • What do I care about?
  • What do I want to protect?
  • What objectives am I trying to achieve? And how?
  • Who might prevent me from achieving these objectives? And how?
  • How have similar people with similar objectives ben thwartede or arrested?
  • If an adversary’s attack is successful, how can I limit the damage done?

Threat modeling is an iterative process. As you ask yourself these questions and write down their answers, you will be able to think of additional threats. Talking to your friends and family may help you identify threats and vulnerabilities, but remember that their threat models are not necessarily your own.

Once you have enumerated the threats, consider the risks associated with each. How likely is it to occur and what are the consequences if it does? These are estimates and meant to help you prioritize which threats need to be addressed first. Threats that have severe consequences but are extremely unlikely might still be ranked as low risk. Threats that are moderately likely with only moderate consequences might be ranked as high risk. Go with your gut when assigning risk and prioritizing the threats.

Once you have listed your threats, consider different mitigations against them. Some mitigations might cover multiple threats at one time, or you may need many mitigations to cover your highest priorit risks. A mitigation may not fully remove a threat or reduce the risk to zero. Mitigations are meant to decrease the amount of risk you face. In addition to thinking about how effective a given mitigation may be against a threat, also consider if you are likely to follow through with this mitigation. A mitigation that you are incapable of executing is not useful.

As you threat model, you may start to feel the perfect security is an impossible goal, and as a result you might as well give up. This is called security nihilism: the belief that because security cannot be “perfect,” any amount of security should be forsaken. Rid yourself of the belief that you are either “secure” or “insecure.” There is no such thing as perfectly secure. There is simply a state of being more secure against certain threats and less secure against those threats. Your goal should be to improve your security, not make it ironclad against all threats.

Lastly, your threat model needs to account for random chance. You may have incredible adept online security, and you may always cover your face and tattoos at actions. Nevertheless, you may have bad luck and have the same daily commute as a detective investigation local activists.

The OpSec two-step

Know what to protect and know how to protect it.

TNU



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