attackers – Alice, Eve and Bob

SVB & finance stress: remember the (other) type of security

Now is the time for more vigilance, not less.

This is the week that the start-up world has been reeling after the collapse of Silicon Valley Bank. There have been lots of articles about it and about how the larger ecosystem (lawyers, VCs, other banks and beyond) have rallied to support those affected, written (on the whole, at least!) by people much better qualified than me to do so. But there’s another point that could get lost in the noise, and that’s the opportunity presented to bad actors by all of this.

When humans are tired, stressed, confused or have too many inputs, they (we – I’ve not succumbed to the lure of ChatGPT yet…) are prone to make poor decisions, or to take less time over decisions – even important decisions – than they ought to. Sadly, bad people know this, and that means that they will be going out of their way to exploit us (I’m very aware that I’m as vulnerable to this type of exploitation as anybody else). The problem is that when banks start looking dodgy, or when money is at stake, people need to do risky things. And these are often risky things which involve an awful lot of money, things like:

withdrawing large amounts of money
moving large amounts of money between accounts
opening new accounts
changing administrative access permissions and privileges on accounts
adding new people as administrators on accounts.

All of the above are actions (or involve actions) which we would normally be very careful about, and take very seriously (though that doesn’t stop us making the occasional mistake). The problem (and the opportunity for bad actors) is that when we’re stressed or in a hurry (as we’re likely to be in the current situation), we may pay less attention to important steps than we might otherwise. We might not enable multi-factor authentication, we might not check website certificates, we might click-through on seemingly helpful offers in emails to help us out, or we might not check the email addresses to which we’re sending invitations. All of these could lead bad folks to get at our money. They know this, and they’ll be going out of their way to find ways to encourage us to make mistakes, be less careful or hurry our way through vital processes.

My plea, then, is simple: don’t drop your guard because of the stress of the current situation. Now is the time for more vigilance, not less.

Masks, vaccinations, social distancing – and cybersecurity

The mappingn the realms of cybersecurity and epidemiology is not perfect, but metaphors can be useful.

Waaaaay back in 2018 (which seems a couple of decades ago now), I wrote an article called Security patching and vaccinations: a surprising link. In those days, Spectre and Meltdown were still at the front of our minds, and the impact of something like Covid-19 was, if not unimaginable, then far from what most of us considered in our day-to-day lives. In the article, I argued that patching of software and vaccination (of humans or, I guess, animals[1]) had some interesting parallels (the clue’s in the title, if I’m honest). As we explore the impact of new variants of the Covid-19 virus, the note that “a particular patch may provide resistance to multiple types of attack of the same family, as do some vaccinations” seems particularly relevant. I also pointed out that although there are typically some individuals in a human population for whom vaccination is too risky, a broad effort to vaccinate the rest of the population has positive impact for them; in a similar way to how patching most systems in a deployment can restrict the number of “jumping off points” or attack.

I thought it might be interesting to explore other similarities between disease management in the human sphere with how we do things in cybersecurity, not because they are exact matches, but because they can be useful metaphors to explain to colleagues, family and friends what we do.

Vaccinations

We’ve looked a vaccinations a bit above: the key point here is that once a vulnerability is discovered, software vendors can release patches which, if applied correctly, protect the system from those attacks. This is not dissimilar in effect to the protection provided by vaccinations in human settings, though the mechanism is very different. Computer systems don’t really have an equivalent to anti-bodies or immune systems, but patches may – like vaccines – provide protection for more than one specific attack (think virus strain) if others exploit the same type of weakness.

Infection testing

As we have discovered since the rise of Covid-19, testing of the population is a vital measure to understand what other mechanisms need to be put in place to control infection. The same goes for cybersecurity. Testing the “health” of a set of systems, monitoring their behaviour and understanding which may be compromised, by which attacks, leveraging which vulnerabilities, is a key part of any cybersecurity strategy, and easily overlooked when everything seems to be OK.

Masks

I think of masks as acting a little like firewalls, or mechanisms like SELinux which act to prevent malicious programs from accessing parts of the system which you want to protect. Like masks, these mechanisms reduce the attack surface available to bad actors by stopping up certain “holes” in the system, making it more difficult to get in. In the case of firewalls, it’s network ports, and in the case of SELinux, it’s activities like preventing unauthorised system calls (syscalls). We know that masks are not wholly effective in preventing transmission of Covid-19 – they don’t give 100% protection from oral transmission, and if someone sneezes into your eye, for instance, that could lead to infection – but we also know that if two people are meeting, and they both wear masks, the chance of transmission from an infected to an uninfected person is reduced. Most cybersecurity controls aim mainly to protect the systems on which they reside, but a well thought-out deployment may also aim to put in controls to prevent attackers from jumping from one system to another.

Social distancing

This last point leads us to our final metaphor: social distancing. Here, we put in place controls to try to make it difficult for an attacker (or virus) to jump from one system to another (or human to another). While the rise of zero trust architectures has led to something of a down-playing of some of these techniques within cybersecurity, mechanisms such as DMZs, policies such as no USB drives and, at the extreme end, air-gapping of systems (where there is no direct network connection between them) all aim to create physical or logical barriers to attacks or transmission.

Conclusion

The mapping between controls in the realms of cybersecurity and epidemiology is not perfect, but metaphors can be useful in explaining the mechanisms we use and also in considering differences (is there an equivalent of “virus load” in computer systems, for instance?). If there are lessons we can learn from the world of disease managemet, then we should be keen to do so.

1 – it turns out that you can actually vaccinate plants, too: neat.

Why physical compromise is game over

Systems have physical embodiments and are actually things we can touch.

This is an edited excerpt from my forthcoming book on Trust in Computing and the Cloud for Wiley.

We spend a lot of our time – certainly I do – worrying about how malicious attackers might break into systems that I’m running, architecting, designing, implementint or testing. And most of that time is spent thinking about logical – that is software-based – attacks. But these systems don’t exist solely in the logical realm: they have physical embodiments, and are actually things we can touch. And we need to worry about that more than we typically do – or, more accurately, more of us need to worry about that.

If a system is compromised in software, it’s possible that you may be able to get it back and clean, but there is a general principle in IT security that if an attacker has physical access to a system, then that system should be considered compromised. In trust terms (something I care about a lot, given my professional interests), “if an attacker has physical access to a system, then any assurances around expected actions should be considered reduced or void, thereby requiring a re-evaluation of any related trust relationships”. Tampering (see my previous article on this, Not quantum-safe, not tamper-proof, not secure) is the typical concern when considering physical access, but exactly what an attacker will be able to achieve given physical access will depend on a number of factors, not least the skill of the attacker, resources available to them and the amount of time they have physical access. Scenarios range from an unskilled person attaching a USB drive to a system in short duration Evil Maid[1] attacks and long-term access by national intelligence services. But it’s not just running (or provisioned, but not currently running) systems that we need to be worried about: we should extend our scope to those which have yet to be provisioned, or even necessarily assembled, and to those which have been decommissioned.

Many discussions in the IT security realm around supply chain, concentrate mainly on software, though there are some very high profile concerns that some governments (and organisations with nationally sensitive functions) have around hardware sourced from countries with whom they do not share entirely friendly diplomatic, military or commercial relations. Even this scope is too narrow: there are many opportunities for other types of attackers to attack systems at various points in their life-cycles. Dumpster diving, where attackers look for old computers and hardware which has been thrown out by organisations but not sufficiently cleansed of data, is an old and well-established technique. At the other end of the scale, an attacker who was able to get a job at a debit or credit card personalisation company and was then able to gain information about the cryptographic keys inserted in the bank card magnetic strips or, better yet, chips, might be able to commit fraud which was both extensive and very difficult to track down. None of these attacks require damage to systems, but they do require physical access to systems or the manufacturing systems and processes which are part of the systems’ supply chain.

An exhaustive list and description of physical attacks on systems is beyond the scope of this article (readers are recommended to refer to Ross Anderson’s excellent Security Engineering: A Guide to Building Dependable Distributed Systems for more information on this and many other topics relevant to this blog), but some examples across the range of threats may serve to give an idea of sort of issues that may be of concern.

Attack	Level of sophistication	Time required	Defences
USB drive to retrieve data	Low	Seconds	Disable USB ports/use software controls
USB drive to add malware to operating system	Low	Seconds	Disable USB ports/use software controls
USB drive to change boot loader	Medium	Minutes	Change BIOS settings
Attacks on Thunderbolt ports[2]	Medium	Minutes	Firmware updates; turn off machine when unattended
Probes on buses and RAM	High	Hours	Physical protection of machine
Cold boot attack[3]	High	Minutes	Physical protection of machine/TPM integration
Chip scraping attacks	High	Days	Physical protection of machine
Electron microscope probes	High	Days	Physical protection of machine

The extent to which systems are vulnerable to these attacks varies enormously, and it is particularly notable that systems which are deployed at the Edge are particularly vulnerable to some of them, compared to systems in an on-premises data centre or run by a Cloud Service Provider in one of theirs. This is typically either because it is difficult to apply sufficient physical protections to such systems, or because attackers may be able to achieve long-term physical access with little likelihood that their attacks will be discovered, or, if they are, with little danger of attribution to the attackers.

Another interesting point about the majority of the attacks noted above is that they do not involve physical damage to the system, and are therefore unlikely to show tampering unless specific measures are in place to betray them. Providing as much physical protection as possible against some of the more sophisticated and long-term attacks, alongside visual checks for tampering, is the best defence for techniques which can lead to major, low-level compromise of the Trusted Computing Base.

1 – An Evil Maid attack assumes that an attacker has fairly brief access to a hotel room where computer equipment such as a laptop is stored: whilst there, they have unfettered access, but are expected to leave the system looking and behaving in the same way it was before they arrived. This places some bounds on the sorts of attacks available to them, but such attacks are notoriously different to defend.

2 – I wrote an article on one of these: Thunderspy – should I care?

2- A cold boot attack allows an attacker with access to RAM to access data recently held in memory.

Thunderspy – should I care?

Thunderspy is a nasty attack, but easily prevented.

There’s a new attack out there which is getting quite a lot of attention this week. It’s called Thunderspy, and it uses the Thunderbolt port which is on many modern laptops and other computers to suck data from your machine. I thought that it might be a good issue to cover this week, as although it’s a nasty attack, there are easy ways to defend yourself, some of which I’ve already covered in previous articles, as they’re generally good security practice to follow.

What is Thunderspy?

Thunderspy is an attack on your computer which allows an attacker with moderate resources to get at your data under certain circumstances. The attacker needs:

physical access to your machine – not for long (maybe five minutes), but they do need it. This type of attack is sometimes called an “evil maid” attack, as it can be carried out by hotel staff with access to your room;
the ability to take your computer apart (a bit) – all we’re talking here is a screwdriver;
a little bit of hardware – around $400 worth, according to one source;
access to some freely available software;
access to another computer at the same time.

There’s one more thing that the attacker needs, and that’s for you to leave your computer on, or in suspend mode. I’ve discussed different power modes before (in 3 laptop power mode options), and mentioned, as well, that leaving your machine in suspend mode is generally a bad idea (in 7 security tips for travelling with your laptop). It turns out I was right.

What’s the bad news?

Well, there’s quite a lot of bad news:

lots of machines have Thunderbolt ports (you can find pictures of both the port and connectors on Wikipedia’s Thunderbolt page, in case you’re not sure whether your machine is affected);
machines are vulnerable even if you have full disk encryption;
Windows machines are vulnerable;
Linux machines are vulnerable;
Macintosh machines are vulnerable;
most machines with a Thunderbolt port from 2011 onwards are vulnerable;
although protection is available on some newer machines (from around 2019)
- the extent of its efficacy is unclear;
- lots of manufacturers don’t implement it;
some protections that you can turn on break USB and other functionality;
one variant of the attack breaks Thunderbolt security permanently, meaning that the attacker won’t need to take your computer apart at all for subsequent attacks: they just need physical access to the port whilst your machine it turned on (or in suspend mode).

The worst thing to note is that full disk encryption does not help you if your computer is turned on or in suspend mode.

Note – I’ve been unable to find out whether any Chromebooks have Thunderbolt support. Please check your model’s specifications or datasheet to be certain.

What’s the good news?

The good news is short and sweet: if you turn your computer completely off, or ensure that it’s in Hibernate mode, then it’s not vulnerable. Thunderspy is a nasty attack, but it’s easily prevented.

What should I do?

Turn your computer off when you leave it unattended, even for short amounts of time.

That was easy, wasn’t it? This is best practice anyway, and it turns out that hibernate mode is also OK. What the attacker is looking for is a powered-up, logged-on computer with Thunderbolt. If you can stop them finding a computer that meets those criteria, then you’re fine. Putting your computer into hibernate mode is also OK.

Avoid: a) contact; b) phishing.

It is impossible to ascertain at first look whether a phishing email is genuine or not.

I was thinking about not posting this week, as many, many of us have rather a lot on our minds at the moment. Like the rest of the UK, our household is in lock-down, and I’m trying to juggle work with the (actually very limited) demands of my two children, alongside my wife. So far, our broadband is holding out, and I’ve worked from home long enough that I’ve managed to get the rest of the family’s remote access issues sorted so far.

But I decided that I wanted to post, because I wanted to issue a warning, in case you’ve missed it elsewhere: watch out for phishing emails.

I try to keep these articles relevant to people who aren’t IT professionals: “technically credible, but something you could show to your parents or your manager”. Given how many parents (not to mention grandparents and, scarily, managers) seem to be going online for pretty much the first time, here’s my first definition of phishing emails[1].

“A phishing email is one which pretends to be from a person or company you trust, trying to get personal details such as logins or bank information, or to install malicious software on your device.”

Here’s my second definition, particularly relevant now.

“A phishing email is one sent by low-lives who are attempting to scam vulnerable, scared people for their own personal gain.”

Many phishing emails look exactly the same as a normal email from the relevant party. To be clear, it is impossible for anyone, even an expert, to ascertain at first look whether a polished and sophisticated phishing email is genuine or not. There are ways to tell, if you’re an expert, by looking in more detail at the actual details of the email, but most people will not be able to tell. I have nearly been caught over the past week, as have one of my kids and my wife. Two that have come round recently were particularly impressive: one from Netflix, and one for the TV licensing authority in the UK. Luckily, I’ve trained my family well, and they knew what to do, which is this:

NEVER CLICK ON ANY LINKS IN AN EMAIL.

There. That’s all you need to do. If you get an email which is asking you to click on a link, a graphic or a picture, don’t do it. Instead, go to the website of the actual company or organisation, or contact the individual who allegedly sent it to you. You should easily be able to work out whether your credit card has been declined, your email account has been suspended, you need to pay extra tax within the next 24 hours (hint: you don’t), your friend is stuck in Tenerife or you have used up all of your phone data. If in doubt, stay calm, don’t panic, and contact a more expert friend[2], and get them to help.

To be clear, it’s easy to get it wrong. I work in IT security, and I’ve been caught in the past: see my article I got phished this week: what did I do? This will also tell you (or your designated expert) what to do in the event that you do click on the link.

And, of course, keep safe.

1 – the word “phishing” is derived from “fishing”, as the emails are “fishing” for your details. The “ph” is a standard geek affectation.

2 – often, but not always, son or daughter, grandson or granddaughter[3].

3 – or one of the people whose manager you are, of course.

Learn to hack online – h4x0rz and pros

Removing these videos hinders defenders much more significantly than it impairs the attackers.

Over the past week, there has been a minor furore over YouTube’s decision to block certain “hacking” videos. According to The Register, the policy first appeared on the 5th April 2019:

“Instructional hacking and phishing: Showing users how to bypass secure computer systems or steal user credentials and personal data.”

Now, I can see why they’ve done this: it’s basic backside-covering. YouTube – and many or the other social media outlets – come under lots of pressure from governments and other groups for failing to regulate certain content. The sort of content to which such groups most typically object is fake news, certain pornography or child abuse material: and quite rightly. I sympathise, sometimes, with the social media giants as they try to regulate a tidal wave of this sort or material – and I have great respect for those employees who have to view some of it – having written policies to ban this sort of thing may not deter many people from posting it, but it does mean that the social media companies have a cast-iron excuse for excising it when they come across it.

Having a similar policy to ban these types of video feels, at first blush, like the same sort of thing: you can point to your policy when groups complain that you’re hosting material that they don’t like – “those dangerous hacking videos”.

Hacking[3] videos are different, though. The most important point is that they have a legitimate didactic function: in other words, they’re useful for teaching. Nor do I think that there’s a public outcry from groups wanting them banned. In fact, they’re vital for teaching and learning about IT security, and most IT security professionals and organisations get that. Many cybersecurity techniques are difficult to understand properly when presented as theoretical attacks and, more importantly, they are difficult to defend against without detailed explanation and knowledge. This is the point: these instructional videos are indispensable tools to allow people not just to understand, but to invent, apply and maintain defences and mitigations against known attacks. IT security is hard, and we need access to knowledge to help us defeat the Bad Folks[tm] who we know are out there.

“But these same Bad Folks[tm] will see these videos online and use them against us!” certain people will protest. Well, yes, some will. But if we ban and wipe them from widely available social media platforms, where they are available for legitimate users to study, they will be pushed underground, and although fewer people may find them, the nature of our digital infrastructure means that the reach of those few people is still enormous.

And there is an imbalance between attackers and defenders: this move exacerbates it. Most defenders look after small numbers of systems, but most serious attackers have the ability to go after many, many systems. By pushing these videos away from places that many defenders can learn from them, we have removed the opportunity for those who most need access to this information, whilst, at the most, raising the bar for those against who we are trying to protect.

I’m sure there are numbers of “script-kiddy” type attackers who may be deterred or have their access to these videos denied, but they are significantly less of a worry than motivated, resourced attackers: the ones that haunt many IT security folks’ worst dreams. We shouldn’t use a mitigation against (relatively) low-risk attackers remove our ability to defend against higher risk attackers.

We know that sharing of information can be risky, but this is one of those cases in which the risks can be understood and measured against others, and it seems like a pretty simple calculation this time round. To be clear: the (good) many need access to these videos to protect against the (malicious) few. Removing these videos hinders the good much more significantly than it impairs the malicious, and we, as a community, should push back against this trend.

1 – it’s pronounced “few-ROAR-ray”. And “NEEsh”. And “CLEEK”[2].

2 – yes, I should probably calm down.

3 – I’d much rather refer to these as “cracking” videos, but I feel that we probably lost that particular battle about 20 years ago now.

Are my messages safe? No, but…

“Are any of these messaging services secure?”

Today brought another story about insecurity of a messenger app, and by a brilliant coincidence, I’m listening to E.L.O.’s “Secret Messages” as I start to compose this post. This article isn’t, however, about my closet 70s musical tastes[1], but about the messages you send from your mobile phone, tablet or computer to friends, families and colleagues, and how secure they are.

There are loads of options out there for messaging services, with some of the better-known including WhatsApp, Facebook Messenger, Google Chat, Signal and Telegram. Then there’s good old SMS. First question first: do I use any of these myself? Absolutely. I also indulge in Facebook, LinkedIn and Twitter. Do I trust these services? Let’s get back to this question later.

A more pressing question might be: “are any of these messaging services secure?” It turns out that this is a really simple question to answer: of course they’re not. No service is “secure”: it’s a key principle of IT security that there is no “secure”. This may sound like a glib – and frankly unhelpful – answer, but it’s not supposed to be. Once you accept that there is no perfectly secure system, you’re forced to consider what you are trying to achieve, and what risks you’re willing to take. This is a recurring theme of this blog, so regular readers shouldn’t be surprised.

Most of the popular messaging services can be thought of as consisting of at least seven components. Let’s assume that Alice is sending a message from her phone to Bob’s phone. Here’s what the various components might look like:

Alice’s messenger app
Alice’s phone
Communications channel Alice -> server
Server
Communications channel server -> Bob
Bob’s phone
Bob’s messenger app

Each of these is a possible attack surface: combined, they make up the attack surface for what we can think of as the Alice <-> Bob and messaging system.

Let’s start in the middle, with the server. For Alice and Bob to be happy with the security of the system for their purposes, they must be happy that this server has sufficiently secure to cope with whatever risks they need to address. So, it may be that they trust that the server (which will be run, ultimately, by fallible and possibly subornable humans who also are subject to legal jurisdiction(s)) is not vulnerable. Not vulnerable to whom? Hacktivists? Criminal gangs? Commercial competitors? State actors? Legal warrants from the server’s jurisdiction? Legal warrants from Alice or Bob’s jurisdiction(s)? The likelihood of successful defence against each of these varies, and the risk posed to Alice and Bob by each is also different, and needs to be assessed, even if that assessment is “we can ignore this”.

Each of the other components is subject to similar questions. For the communication channels, we will assume that they’re encrypted, but we have to be sure that the cryptography and cryptographic protocols have been correctly implemented, and that all keys are appropriately protected by all parties. The messaging apps must be up to date, well designed and well implemented. Obviously, if they’re open source, you have a much, much better chance of being sure of the security of both software (never, ever use cryptography or protocols which have not been not open sourced and peer reviewed: just don’t). The phones in which the software is running must also be uncompromised – not to mention protected by Alice and Bob from physical tampering and delivered new to them from the manufacturer with no vulnerabilities[2].

How sure are Alice and Bob of all of the answers to all of these questions? The answer, I would submit, is pretty much always going to be “not completely”. Does this mean that Alice and Bob should not use messaging services? Not necessarily. But it does mean that they should consider what messages they should exchange via any particular messaging service. They might be happy to arrange a surprise birthday party for a colleague, but not to exchange financial details of a business deal. They might be happy to schedule a trip to visit a Non-Governmental Organisation to discuss human rights, but not to talk about specific cases over the messaging service.

This is the view that I take: I consider what information I’m happy to transfer over or store on messaging services and social media platforms. There are occasions where I may happy to pass sensitive data across messaging services, but break the data up between different services (using “different channels” in the relevant parlance): using one service for a username and another for the associated password, for instance. I still need to be careful about shared components: the two phones in the example above might qualify, but I’ve reduced the shared attack surface, and therefore the risk. I’m actually more likely to require that the password is exchanged over a phone call, and if I’m feeling particularly paranoid, I’ll use a different phone to receive that call.

My advice, therefore, is this:

Keep your devices and apps up to date;
Evaluate the security of your various messaging service options;
Consider the types of information that you’ll be transferring and/or storing;
Think about the risks you’re willing to accept;
Select the appropriate option on a case by case basis:
Consider using separate channels where particularly sensitive data can be split for added security.

1 – I’m also partial to 1920’s Jazz and a bit of Bluegrass, as it happens.

2 – yeah, right.

I’m turning off your security.

“Don’t worry, I know what I’m doing.”

Today’s security story is people turning security off. For me, the fact that it’s even a story is the story. This particular story is covered in The Register, who explain (to nobody’s surprise) that some of the patches to fix issues identified in CPU’s (think Spectre, Meltdown, etc.) can actually slow down the applications running on them. The problem is that, in some cases, they don’t slow them down a little bit, but rather a lot. By which I mean up to 50%. And if you’ve bought expensive hardware – or rented it [1] – then you’d generally prefer it if it runs your applications/programs/workloads quickly, rather than just half as fast as they might run.

And so you turn off the security patches. Your decision: fine.

No, stop: this isn’t what has happened.

The mythical “you”, the person running the workload, isn’t the person who makes the decision, in most cases, because it’s been made for you. This is the real story.

Linus Torvalds, and a bunch of other experts in the Linux kernel[2], have decided that although the patch that could make your workloads secure is available, the functionality that does it should be “off” by default. They reason – quite correctly, in my opinion – that the vast majority of people running workloads, won’t easily be able to turn this functionality on themselves

They also reason – again, correctly, in my opinion – that most people will care more about how quickly their workloads run than about how secure they are. I’m not happy about this, but that’s the way it is.

What I worry about is the final step in the logic to making the decision. I’m going to quote Linus:

“Have you seen any actual realistic attacks for normal human users?” he asked. “Things where the kernel should actually care? The JavaScript thing is for the browser to fix up, not for the kernel to say ‘now everything should run up to 50 per cent slower.'”

I get the reasoning behind this, but I don’t like it. To give some context, somebody came up with an example attack which could compromise certain workloads, and Linus points out that there are better ways to fix this attack than fixing it in the kernel. My concerns are two-fold:

although there may be better places to fix that particular attack, a kernel-level fix is likely to fix an entire class of attacks, meaning better protection for users who are using any application which might include an attack vector.
pointing out that there haven’t been any attacks yet not only ignores the fact that there is a future out there[3] but also points malicious actors in the direction of a likely attack vector.

Now, I know that the more dedicated malicious actors are already looking for these things, but do we really need to advertise?

What’s my fix?

I don’t have one, or at least not an easy one.

Somebody, somewhere, needs to decide whether security is turned on or off. What I’d honestly like to see is an easier set of controls to allow people to turn on or off security, and to understand the trade-offs when they do that. The problems with that are:

the trade-offs are often much more complex than just “fast and insecure” or “slow and secure”, and are really difficult to explain.
in order to make a sensible decision about trade-offs, people need to understand risk. And people are awful at understanding risk.

And there’s a “chicken and egg problem”[7] here: people won’t understand risk until they are offered the chance to make decisions, but there’s little incentive to offer them complex decisions unless they understand risk.

My plea? Where possible, expose risk, and explain what it is. And if you’re turning off security-related functionality, make it easy to turn back on for those who need it.

1 – a quick heads-up: this is what “deploying to the cloud” actually is.

2 – what sits at the bottom of many of the workloads that are running in servers.

3 – hopefully. If the Three Minute Warning[4] sounds while you’re reading this, you may wish to duck and cover. You can come back to it later[6].

4 – “… sounds like this …”[5].

5 – 80s reference.

6 – or not. See [3].

7 – for non-native English readers, this means “a problem where the solution requires two pieces, both of which are dependent on each other”.

3 laptop power mode options

Don’t suspend your laptop.

I wrote a post a couple of weeks ago called 7 security tips for travelling with your laptop. The seventh tip was “Don’t suspend”: in other words, when you’re finished doing what you’re doing, either turn your laptop off, or put it into “hibernate” mode. I thought it might be worth revisiting this piece of advice, partly to explain the difference between these different states, and partly to explain exactly why it’s a bad idea to use the suspend mode. A very bad idea indeed. In fact, I’d almost go as far as saying “don’t suspend your laptop”.

So, what are the three power modes usually available to us on a laptop? Let’s look at them one at a time. I’m going to assume that you have disk encryption enabled (the second of the seven tips in my earlier article), because you really, really should.

Power down

This is what you think it is: your laptop has powered down, and in order to start it up again, you’ve got to go through an entire boot process. Any applications that you had running before will need to be restarted[1], and won’t come back in the same state that they were before[2]. If somebody has access to your laptop when you’re not there, then there’s not immediate way that they can get at your data, as it’s encrypted[3]. See the conclusion for a couple of provisos, but powering down your laptop when you’re not using it is pretty safe, and the time taken to reboot a modern laptop with a decent operating system on it is usually pretty quick these days.

It’s worth noting that for some operating systems – Microsoft Windows, at least – when you tell your laptop to power down, it doesn’t. It actually performs a hibernate without telling you, in order to speed up the boot process. There are (I believe – as a proud open source user, I don’t run Windows, so I couldn’t say for sure) ways around this, but most of the time you probably don’t care: see below on why hibernate mode is pretty good for many requirements and use cases.

Hibernate

Confusingly, hibernate is sometimes referred to as “suspend to disk”. What actually happens when you hibernate your machine is that the contents of RAM (your working memory) are copied and saved to your hard disk. The machine is then powered down, leaving the state of the machine ready to be reloaded when you reboot. When you do this, the laptop notices that it was hibernated, looks for saved state, and loads it into RAM[4]. Your session should come back pretty much as it was before – though if you’ve moved to a different wifi network or a session on a website has expired, for instance, your machine may have to do some clever bits and pieces in the background to make things as nice as possible as you resume working.

The key thing about hibernating your laptop is that while you’ve saved state to the hard drive, it’s encrypted[3], so anyone who manages to get at your laptop while you’re not there will have a hard time getting any data from it. You’ll need to unlock your hard drive before your session can be resumed, and given that your attacker won’t have your password, you’re good to go.

Suspend

The key difference between suspend and the other two power modes we’ve examined above is that when you choose to suspend your laptop, it’s still powered on. The various components are put into low-power mode, and it should wake up pretty quickly when you need it, but, crucially, all of the applications that you were running beforehand are still running, and are still in RAM. I mentioned in my previous post that this increases the attack surface significantly, but there are some protections in place to improve the security of your laptop when it’s in suspend mode. Unluckily, they’re not always successful, as was demonstrated a few days ago by an attack described by the Register. Even if your laptop is not at risk from this particular attack, my advice just not to use suspend.

There are two usages of suspend that are difficult to manage. The first is when you have your machine set to suspend after a long period of inactivity. Typically, you’ll set the screen to lock after a certain period of time, and then the system will suspend. Normally, this is only set for when you’re on battery – in other words, when you’re not sat at your desk with the power plugged in. My advice would be to change this setting so that your laptop goes to hibernate instead. It’s a bit more time to boot it up, but if you’re leaving your laptop unused for a while, and it’s not plugged in, then it’s most likely that you’re travelling, and you need to be careful.

The second is when you get up and close the lid to move elsewhere. If you’re moving around within your office or home, then that’s probably OK, but for anything else, try training yourself to hibernate or power down your laptop instead.

Conclusion

There are two important provisos here.

The first I’ve already mentioned: if you don’t have disk encryption turned on, then someone with access to your laptop, even for a fairly short while, is likely to have quite an easy time getting at your data. It’s worth pointing out that you want full disk encryption turned on, and not just “home directory” encryption. That’s because if someone has access to your laptop for a while, they may well be able to make changes to the boot-up mechanism in such a way that they can wait until you log in and either collect your password for later use or have the data sent to them over the network. This is much less easy with full disk encryption.

The second is that there are definitely techniques available to use hardware and firmware attacks on your machine that may be successful even with full disk encryption. Some of these are easy to spot – don’t turn on your machine if there’s anything in the USB port that you don’t recognise[5] – but others, where hardware may be attached or even soldered to the motherboard, or firmware changed, are very difficult to spot. We’re getting into some fairly sophisticated attacks here, and if you’re worried about them, then consider my first security tip “Don’t take a laptop”.

1 – some of them automatically, either as system processes (you rarely have to remember to have to turn networking back on, for instance), or as “start-up” applications which most operating systems will allow you to specify as auto-starting when you log in.

2 – this isn’t actually quite true for all applications: it might have been more accurate to say “unless they’re set up this way”. Some applications (web browsers are typical examples) will notice if they weren’t shut down “nicely”, and will attempt to get back into the state they were beforehand.

3 – you did enable disk encryption, right?

4 – assuming it’s there, and hasn’t been corrupted in some way, in which case the laptop will just run a normal boot sequence.

5 – and don’t just use random USB sticks from strangers or that you pick up in the carpark, but you knew that, right?

What are they attacking me for?

There are three main types of motivations: advantages to them; disadvantages to us; resources.

I wrote an article a few weeks ago called What’s a State Actor, and should I care?, and a number of readers asked if I could pull apart a number of the pieces that I presented there into separate discussions[1]. One of those pieces was the question of who is actually likely to attack me.

I presented a brief list thus:

insiders
script-kiddies
competitors
trouble-makers
hacktivists
… and more.

One specific “more” that I mentioned was State Actors. If you look around, you’ll find all manner of lists. Other attacker types that I didn’t mention in my initial list include:

members of organised crime groups
terrorists
“mercenary” hackers.

I suspect that you could come up with more supersets or subsets if you tried hard enough.

This is all very well, but what’s the value in knowing who’s likely to attack you in the first place[3]? There’s a useful dictum: “No system is secure against a sufficiently resourced and motivated attacker.”[5] This gives us a starting point, because it causes us to ask the question

what motivates the attacker?

In other words: what do they want to achieve? What, in fact, are they trying to do or get when they attack us? This is the core theme of this article.

There are three main types of motivations:

advantages to them
disadvantages to us
resources.

There is overlap between the three, but I think that they are sufficiently separate to warrant separate discussion.

Advantages to them

Any successful attack is arguably a disadvantage to us, the attacked, but that does not mean that the primary motivation of an attacker is necessarily to cause harm. There are a number of other common motivations, including:

reputation or “bragging rights” – a successful attack may well be used to prove the skills of an attacker to other parties.
information to share – sometimes attackers wish to gain information about our systems to share with others, whether for gain or to enhance their reputation (see above). Such attacks may be painted a security research, but if they occur outside an ethical framework (such as provided by academic institutions) and without consent, it is difficult to consider them anything other than hostile.
information to keep – attackers may gain information and keep it for themselves for later use, either against our systems or against similarly configured systems elsewhere.
practice/challenge – there are attacks which are undertaken solely to practice techniques or as a personal challenge (where an external challenge is made, I would categorise them under “reputation”). Harmless as this motivation may seem to some parts of the community, such attacks still cause damage and require mitigation, and should be considered hostile.
for money – some attacks are undertaken at the request of others, with the primary motivation of the attacker being that money or other material recompense (though the motivation of the party commissioning that attack likely to be one of these other ones listed)[6].

Disadvantages to us

Attacks which focus on causing negative impact to the individual or organisation attacked can be listed in the following categories:

business impact – impact to the normal functioning of the organisation or individual attacked: causing orders to be disrupted, processes to be slowed, etc..
financial impact – direct impact to the financial functioning of the attacked party: fraud, for instance.
reputational impact – there have been many attacks where the intention has clearly been to damage the reputation of the attacked party. Whether it is leaking information about someone’s use of a dating website, disseminating customer information or solely replacing text or images on a corporate website, the intention is the same: to damage the standing of those being attacked. Such damage may be indirect – for instance if an attacker were to cause the failure of an oil pipeline, affecting the reputation of the owner or operator of that pipeline.
personal impact – subtly different from reputational or business impact, this is where the attack intends to damage the self-esteem of an individual, or their ability to function professionally, physically, personally or emotionally. This could cover a wide range of attacks such as “doxxing” or use of vulnerabilities in insulin pumps.
ecosystem impact – this type of motivation is less about affecting the ability of the individual or organisation to function normally, and more about affecting the ecosystem that exists around it. Impacting the quality control checks of a company that made batteries might impact the ability of a mobile phone company to function, for instance, or attacking a water supply might impact the ability of a fire service to respond to incidents.

Resources

The motivations for some attacks may be partly or solely to get access to resources. These resources might include:

financial resources – by getting access to company accounts, attackers might be able to purchase items for themselves or others or otherwise defraud the company.
compute resources – access to compute resources can lead to further attacks or be used for purposes such as cryptocurrency mining.
storage resources – attackers may wish to store illegal or compromising material on others’ systems.
network resources – access to network resources allows attackers to launch attacks elsewhere or to stream information with little traceability.
human resources – access to some systems may allow human resources to be deployed in ways unintended by the party being attacked: deploying police officers to a scene a long distance away from a planned physical attack, for instance.
physical resources – access to some systems may also allow physical resources to be deployed in ways unintended by the party being attacked: sending ammunition to the wrong front in a war, might, for example, lead to military force becoming weakened.

Conclusion

It may seem unimportant to consider the motivations of those attacking us, but if we can understand what it is that they are looking for, we can decide what we should defend, and sometimes what types of defence we should put in place. As always, I welcome comments on this article: I’m sure that I’ve missed out some points, or misrepresented others, so please do get in touch and let me know your thoughts.

1 – I considered this a kind and polite way of saying “you stuffed too much into a single article: what were you thinking?”[2]

2 – and I don’t necessarily disagree.

3 – unless you’re just trying to scare senior management[4].

4 – which may be enjoyable, but is ultimately likely to backfire if you’re doing it without evidence and for a good reason.

5 – I made a (brief) attempt to track the origins of this phrase: I’m happy to attribute if someone can find the original.

6 – hat-tip to Reddit user poopin for spotting that I’d missed this one out.