Dependency vulnerabilities: a practical guide

It is rarely the thing that gets a project approved, and often the thing that decides how it goes. This guide covers what dependency vulnerabilities actually involves, where it usually goes wrong, and how to tell whether yours is in reasonable shape.

Security is a maintenance habit rather than a purchase, which is why it drifts. Nothing below assumes a large team or a large budget — most of it is a decision somebody has to make and then write down.

What is actually at stake

Your code is a small part of what you ship. Where this goes wrong is almost never a lack of knowledge. The teams that stay on top of it are the ones who put it on a calendar rather than a wish list.

For most businesses the question is not whether this matters but how much of it is worth doing right now. That depends on what you are trying to achieve in the next few months, not on best practice in the abstract. This is the sort of thing that compounds, quietly, in both directions.

The practical version

Automated alerts catch what manual review never will. In practice this is a scheduling problem more than a technical one. Doing this properly once is usually cheaper than doing it approximately three times.

The realistic threat for most small businesses is automated and opportunistic, not targeted. The version that works in practice is usually less elaborate than the version described in the guides.

Fewer dependencies is a security strategy. That sounds obvious written down. It is still the thing most often skipped. Most teams find the first pass takes an afternoon and the maintenance takes minutes a month.

A working checklist

If you want a quick read on where you stand, work through this. Anything you cannot answer confidently is where to start.

• Your code is a small part of what you ship
• Automated alerts catch what manual review never will
• Fewer dependencies is a security strategy
• Someone is named as the owner, not just assumed to be
• There is a date in the calendar to review it again
• The decision and the reasoning behind it are written down somewhere findable
• You could explain the current setup to a new hire in five minutes

Where it usually goes wrong

The most common failure is not doing this badly. It is doing it once, during a launch, and never revisiting it. Circumstances move, the setup does not, and the gap widens quietly until something breaks or somebody notices the numbers.

• It was configured during a launch and has not been touched since
• Different people in the business believe different things are true about it
• There is no way to tell whether the last change helped or hurt
• The only person who understands it has left, or is about to

The cheapest security work is the boring kind done on a schedule. Getting it slightly wrong is survivable. Ignoring it entirely is not.

How we approach it

On our projects this gets handled during the build rather than added afterwards, because retrofitting it costs several times more than including it. We write down what was decided and why, so the next person to touch it is not guessing.

If you are working with someone else, the questions worth asking are simple: who owns this, how will we know it is working, and what happens when it needs to change?

Making it stick

Pick the single item from the checklist above that would cause the most trouble if it turned out to be wrong. Fix that one, confirm it worked, then move on. If you want a second opinion on how yours is set up, ask.