Security (b)log - English edition: March 2026

2026-03-20

Rusting chains

‘The weakest link in IT security is always the one between the screen and the backrest of the office chair,’ someone joked in the comments under my previous blog. That blog was about WhatsApp and Signal accounts that had been hacked through their owners. Directly opposed to that is a statement by a former general director of our organization: ‘People are the strongest link in security.’ How do these statements relate to each other?

You often hear that first quote. It basically means: the computer user falls for it with eyes wide open because they don’t understand it all. Some even dare to speak of ‘that dumb end user.’ That, at any rate, is unfair: you simply cannot expect every employee to thoroughly understand all the ins and outs of cybercrime and information security or to be constantly alert to suspicious situations. So stupidity is almost never the issue (I will come back to that ‘almost’).

A chain consists of multiple links. According to the old saying, the weakest link determines the strength of the chain as a whole. That saying implies that one link can be designated as the weakest. But what if another link rusts faster and overtakes its already weak neighbor? Then suddenly a different link becomes the weakest. If the chain is then put under tension, it may break in a completely different place than expected. In short: I don’t believe much in the weakest-link theory. What I do believe in is a chain that is regularly maintained. If a weak spot is found, it should be repaired.

The security chain has two kinds of links: technical and human. I am keeping it simpler here than other models because this is all I need to make my point. Ideally, the technology would be able to keep all harm and inconvenience outside. Our mail filters would recognize all phishing attempts and send spam flawlessly to the trash. All DDoS attacks would be repelled before they reached your network. And hackers wouldn’t stand a chance because all break‑in attempts would be crushed instantly.

We all know that this isn’t how things work. A hundred percent protection through technology alone is an illusion. You wouldn’t think so if you walked through a security expo where vendors promote their hardware and software. They always seemed to sell perfect security, and with the rise of AI that has only become ‘worse.’ But reality is different: the links in the chain have some rusty spots. And do you know why that is? Because the links rub against each other. It’s not like one system protects everything; there is interaction. And things can go wrong there. In the interaction between technical systems, but also — more often? — in the interaction between technical and human links. Put simply: if a system gives an alert but the user dismisses it as irrelevant while something is really happening, then you have a serious rust spot.

So, are humans the strongest link? When I first heard that claim, I was surprised, because the weakest‑link theory was widely accepted then. But I have changed my mind since. Nowadays, I tell my audiences that they are indeed the strongest link. The user is my last line of defense — when all technical systems have failed, the human is the only remaining safeguard. At least, for the kinds of trouble in which the user plays a role.

Stupidity is almost never the issue, I wrote. Almost. So does that mean sometimes it is? Yes. It happens that people have a bad feeling — for example, they don’t trust a certain email. And then they still click the link or open the attachment. Just to see what happens. Because they’re curious. Or because they think: well, this isn’t for real, right? That’s not smart. Just follow the simple rule: when in doubt, assume it’s malicious.

And in the big bad world…

2026-03-13

WhatsApp and Signal hacked? No!

Image from Unsplash

Last Monday, Dutch broadcaster NOS ran the headline: ‘Russia hacks WhatsApp and Signal of government employees, intelligence services say.’ Let me explain why I label this as ‘devaluation.’

First, a reassurance: neither WhatsApp nor Signal has been hacked. At least, not if you use the common meaning of hacking: gaining unauthorized access to a computer system (not a formal definition, but the way I see it). In this case, the computer system would be the service as provided by WhatsApp and Signal. Your individual account is not the target.

Let’s pretend for a moment that these chat services really were hacked. That would mean a hacker had broken into their servers and done all sorts of things that many people would not appreciate; all – or at least many – customers would have been affected because their data had been compromised.

But that’s not what happened here at all. The actor (a polite term for perpetrator) targeted individual accounts of specific types of officials. These people received a message that appeared to come from Signal’s chatbot; it looked like an official warning from the service provider about suspicious activity. It also claimed that data might have leaked and that attempts had been detected to access private information. You could prevent this, the message said, by completing the verification process.

So what is actually happening? The actor wants to log in to your Signal account. The app then asks for a code, which is sent by SMS to the phone number Signal knows: yours. The actor needs that code, and your self‑chosen PIN, to log in. Hence the message they send you. The idea is to make you panic so that you quickly complete the ‘verification process’, which really is a trap. If you fall for it, the actor can take over your entire account and even change the linked phone number to their own. They now have access to your contacts and can read new chat messages (both one‑to‑one and in groups). They can even send messages as you. You lose access to your account, but you can create a new one and get your chat history back – because it is stored on your device. Great, no problem, nice that they helped me so well, you might think.

In another variant, they have you scan a QR code or click a link. They make you believe you are being added to a WhatsApp or Signal group chat, but in reality the attacker’s device becomes linked to your account. The actor can now see all your chats, often including chat history. You notice nothing. In this attack as well, they can read new messages and send messages on your behalf.

Now, back to the term hacking and why I think it is being devalued. From the 1960s onward, a hack was a clever technical trick in the (American) computer and model railway club world, and a hacker was an exceptionally smart programmer. In the 1980s, the term was used for people who conducted in‑depth research into computer systems and networks. If they bypassed security, it was out of curiosity and in order to test things. There were also crackers, their malicious counterparts. From the 1990s onward, the distinction faded and hackers came to be seen as criminals in general. See my personal definition above.

The NOS headline suggests that WhatsApp and Signal have been hacked, while the cyber advisory from Dutch intelligence services explicitly emphasizes that this is not the case. Apparently, NOS was reprimanded, or the editorial team corrected the intern, because later that day the headline changed to: ‘Intelligence services: Russian hackers access WhatsApp and Signal accounts of civil servants.’ And the article gained a paragraph titled: ‘No breach in the messaging service itself.’ In the original version, ‘hacking’ seemed to refer to pretty much all computer‑related trouble coming from the outside. As described above, the term was already significantly devalued, but this was simply misleading.

What actually happened here is called social engineering. In this technique, it is not the computer but the human behind the computer that is attacked. If they succeed in getting you to share a code or scan a QR code, their mission is accomplished. Social engineering is also known as hacking the human – which, ironically, is accurate.

And in the big bad world…

2026-03-06

Poor crisis communication

Photo by author

It is not my habit to blog about the same topic two weeks in a row. But this time, they really asked for it.

Yes, I'm talking about the data theft at Odido again. Last week I wrote that the press mainly portrayed Odido as a victim: they were hacked, so they must be pitied. But they weren't ‘hardcore hacked’ at all: the criminals got in through phishing combined with other forms of social engineering. They simply walked through the front door and downloaded all that data. That victim narrative is becoming less and less tenable, and the press has now picked up on that as well. Odido is facing increasing scrutiny.

The company is in crisis, and that requires solid communication. So how are they doing on that front? Well, not great. Let me be clear: I’m not an expert in crisis communication. A teammate of mine is – he completed a training program in crisis management and crisis communication. Do you know the first thing he said when I asked him about the essence of good crisis communication? Openness and transparency. Followed by speed, honesty, and taking initiative.

Earlier this week I spoke with people from various organizations. What I heard was not encouraging. One company had been told that only the data of administrators with an account on Odido’s business portal had been affected. But shortly after, employees began complaining, and it turned out that the data of several thousand employees had been leaked. People also grumbled about the very poor and sometimes simply incorrect information coming from the telecom company.

On February 13, I received an email from Odido stating that my data, as a former customer, had been leaked. I was a T-Mobile customer until 2019, the predecessor of Odido. The company wrote: ‘Odido retains – according to our privacy statement – your contact details for up to 2 years after termination of the contract and switching to another provider. Because you switched less than 2 years ago, your details were still in the system, and that is why you received this email.’ A quick calculation shows that something doesn’t add up.

The same email also stated: ‘What has not been leaked: Identification data: number and validity of your passport or driver's license.’ However, on the company’s information page – which is still difficult to find – it does state that this information has been leaked. But apparently that wasn’t important enough to send a follow-up email.

On March 1, haveibeenpwned.com notified me that my data had been leaked via Odido, and three days later my VPN provider sent a similar notification. They had even more information: through their Dark Web Monitor they could specify precisely which data had been leaked. This included the number of an ID card – the card shown here – which was valid until 2016. I had missed Odido’s email because it was sent to an account I rarely check; I only just found it. You can imagine my shock that such an old ID card surfaced while (I believed) Odido had not informed me at all. It shows at the very least that Odido does not comply with its own privacy statement. Let alone the GDPR, which explicitly states that personal data must not be retained longer than necessary. Holding data belonging to someone who was a customer of their legal predecessor seven years ago is absurd.

My knowledgeable colleague said that good communication can actually strengthen your position during a crisis, by showing honesty and integrity. These qualities are in short supply at Odido. What doesn’t help is that the company’s spokesperson badly mispronounced ‘cybercriminals’ in an interview with the Dutch public broadcaster NOS. That level of cluelessness and lack of interest is downright embarrassing. My colleague also noted (thanks, Rico) that it is far more effective to present yourself not as a victim, but as a problem-solver. I’m seeing very little of that so far. Their communication about not paying the ransom – which is a defensible choice – comes down to three sentences on that hard-to-find information page: ‘We have made a careful assessment. Leading experts and government bodies have urgently advised us not to engage with this criminal group. This advice is based on extensive experience with this specific group.’ There is no trace of empathy toward customers. Again, I don’t need them to pay, but I do expect them to clearly explain why they are not paying.

The day before yesterday, I wanted to ask my bank something. The first question their chatbot asked me was: ‘Are you chatting with us because of the recent cyberattack at Odido?’ The chatbot explained that my bank account was safe and provided additional information about data breaches in general. Now that is smart communication.