Threat modeling the quick and dirty way

Basic choreography

Step 1. Set up a table

The first column contains a short description of the threat, the second the likelihood of it occurring, the third what impact it would have if it did happen, and the fourth an assessment (grade) of the time and energy you would need to protect yourself from the threat (for instance you can have no stars denote that there is no protection from that threat, hence it will cost nothing (except for the cost of the impact if it did happen).

Step 2. Fill in the table

I recommend doing a brainstorm on threats as initial filling of the threat columns in the table, before thinking about the other columns.

Threat	Likelihood	Impact	Protection
Having to drink	medium	Developer will drop dead within a week, deadline will not be made. The human body needs water to survive. The maximum time an individual can go without water seems to be a week — an estimate that would certainly be shorter in difficult conditions, like broiling heat.	* Blend together half a gallon of water, three and a half tablespoons of macadamia nut oil and a 16-ounce bag of powder called Schmoylent. Then pour the beige beverage into jars and chill them before bringing the containers to work the next day http://timesofindia.indiatimes.com/tech/jobs/No-time-to-eat-Silicon-Valley-drinks-its-meals/articleshow/47424226.cms
Having to eat food	high	Developer will drop dead within three weeks, deadline will not be made. A human can go for more than three weeks without food (Mahatma Gandhi survived 21 days of complete starvation)	* Blend together half a gallon of water, three and a half tablespoons of macadamia nut oil and a 16-ounce bag of powder called Schmoylent. Then pour the beige beverage into jars and chill them before bringing the containers to work the next day http://timesofindia.indiatimes.com/tech/jobs/No-time-to-eat-Silicon-Valley-drinks-its-meals/articleshow/47424226.cms
Needing sleep	high	Like breathing, sleep is essential to humans. It has even been said that one could survive three times longer without food than one could without sleep. One of the better known experiments on this subject, found that depriving rats entirely of sleep resulted in their death, or near-dying state, within 11-32 days (Everson et al. 1989).	** No long term alternatives known, but the deadline is still four weeks off. We tried adding coffee and coke to the Schmoylent in the previous development cycle.
Bathroom breaks	high	How many times do people go to the bathroom per day? Loads, and all those little breaks can add up to an hour or two per developer per day.	***** Implanting stomata. Costly. Management has suggested we need more surveillance equipment to study the problem of the breaks.

Step 3. Reorder the list according to your set of priorities

Choose your ordering strategy carefully. Several strategies are possible.

If this is a learning experience or you are a fan of "only time for putting out fires" cultures, no need for ordering.
In a low risk environment (no immediate death threats) an "on demand" strategy works well. In this strategy you can use "low hanging fruit" and set up protection for items with a big impact and/or high likelihood of occurrence first.
In a high risk environment or if any of the items in the list of possible impacts reads " loss of life" or some life-altering experience or you have turned procrastination into an art, best choose an "anticipating strategy", meaning do more research and detailed scenario planning to find possible threats and solutions overlooked.

Examples

Protesting in the united states

Threat	Likelihood	Impact	Protection

Protesting in the westbank and gaza strip

Threat	Likelihood	Impact	Protection

Blogging from egypt

Journalist, observer or sousveillant in europe

A general counter strategy against police misconduct, abuse and brutality has been recording what happens during a protest. This of course, has gotten the police to target (citizen) journalists and observers overtly and covertly. And it is not just the police and government that are interested in us and our data.

Threat	Likelihood	Impact	Protection
Paranoia and metanoia	medium	Metanoia (safety delusion) makes us sitting ducks and paranoia renders us ineffective.	* The mental health charity "mind" describes fears as paranoid "when they are exaggerated and there is no evidence that they are true". The key to avoiding slipping into paranoia – and safety delusions – is to ensure that we have a realistic understanding of the risks involved in our role. These will vary, but there will always be risks.
Some contacts are named in reports, and some wish to remain anonymous. If we’re not careful, we might unintentionally disclose contact details or their location http://thenextweb.com/insider/2012/12/03/vice-leaves-metadata-in-photo-of-john-mcafee-pinpointing-him-to-a-location-in-guatemala/	high	Such breaches can diminish trust and be even life threatening to others, and may harm our reputation.
Correspondence with contacts includes all sorts of information that we do not want others to know about	high	Such breaches can diminish trust and be even life threatening to others, and may harm our reputation.
Email, social media accounts, websites, communication tools, a pile of passwords	high	Our passwords may be a means to attack others in our "organisation", and access information we don’t directly hold.
All work-in-progress, files and documents which we couldn’t publish for all sorts of reasons (space, legality, protection of others)	high	Such breaches can diminish trust and be even life threatening to others, and may harm our reputation.
If we use computers in any way (including phones and even photocopiers) we can safely assume we are being recorded	high
It may not be our activities they are interested in, but our reach. An example of this was the Syrian Electronic Army targeting E! Online http://ohnotheydidnt.livejournal.com/77479774.html	medium
Legal attacks: That might include direct approaches such as subpoenas demanding that you reveal a source or court orders to pass over footage, but increasingly it might also include indirect approaches, to companies holding your information.	medium