Today I release DfontSplitter 0.4.2 for Mac. This is a critical security update that fixes an issue relating to the Sparkle software update framework when the update pages are served over HTTP. As of 0.4.2, the update pages are now, naturally, served over HTTPS. (It was more than five years ago when the last release was made!)

The vulnerability means that in a scenario where an attacker could launch a man-in-the-middle attack during a Sparkle-enabled app’s update detection process, arbitrary JavaScript could execute in the WebView hosting the release notes. Due to the context that the WebView runs in, the app could then be convinced to run local files, expose local files to a remote server and even execute arbitrary code. More details and a full breakdown are at the post on Vulnerable Security.

This update fixes the Sparkle-related security issue by updating Sparkle and requiring HTTPS for all future DfontSplitter app update communications. Due to new build requirements in Xcode 7.2, the application now requires at least OS X Snow Leopard (10.6) and a 64-bit Intel processor.

The automatic updates feature within DfontSplitter should detect the update, but you can also download and install it manually.

Thanks to Kevin Chen for pointing out the existence of the issue with Sparkle and that it affected DfontSplitter. I had somehow missed the original reporting of the vulnerability, so I particularly appreciate Kevin bringing this to my timely attention.

The astute among you may note that in the Info.plist for this update, I explicitly disable the OS X 10.11 SDK’s check for HTTPS forward secrecy in the HTTPS communications to the update server. Once I figure out a cipher suite configuration that I am happy with, and understand, in Pound (my reverse proxy acting as the TLS terminus), I will update the app again to require forward secrecy.

The recent news about the bash vulnerability being called “ShellShock”, and the degree to which it is getting mainstream press has got me thinking about how software vulnerabilities are now being reported in the mainstream media.

Apparently, no vulnerability these days is complete without a catchy name and logo — see Heartbleed and Shellshock! Joking aside, though, the very fact that these vulnerabilities are making non-tech news headlines puts pressure on everyone running potentially vulnerable systems to do their duty — usually as straightforward as running a pre-packaged security update.

The Heartbleed and Shellshock stories are taking the place of what we used to see reserved for particularly influental computer worms, like Sasser and Mydoom. It’s most definitely positive that some vulnerabilities are getting attention — unfortunately it is still the case that for some companies and system administrators, only outside pressure will convince them to promptly, diligently and consistently apply security updates.

What I’d like to see, is some way for people interested in improving computer security, the “good guys” for lack of a better term, to leverage this media interest to send a message to system administrators that it’s always necessary to apply software updates promptly, even when they don’t get on the TV news!

The Curse of The Black Box

The other key issue that Shellshock highlights, as did Heartbleed, is the issue of embedded ‘black box’ systems that might be vulnerable. This kind of system is everywhere — and because in many cases they are ‘set it and forget it’ machines, they represent a particular risk. It’s often very difficult to convince vendors of these systems of the importance of pushing upstream software updates down to end users, particularly when there is a lack of understanding and a lack of financial incentive.

Something big and mainstream, like Shellshock and Heartbleed, might convince system administrators to badger vendors to release patches for this kind of product, but we need to extend this further, and make it a social (or even a legal) expectation on vendors to supply security updates for any product they ship, for a reasonable lifetime period for that product.

The security landscape is too complex, and everything too interconnected, for anyone to have the opinion that “I don’t need to patch that, because there’s nothing important on it”.

Leaving Yourself in the Loop

I want to part with a few bullet points, with some actions I try to take to stay up-to-date. Automatic updates are increasingly common, but not universal, and these simple things can help you not miss a known vulnerability.

• Document and understand the whole software footprint of the systems for which you are responsible. (This means embedded systems, software libraries, and more!)
• Subscribe to announce mailing lists, follow Short-Form “Bird” Social Media Site Before It Went Terrible accounts of the software projects and systems you use. (It pays to be in the know about available updates, and not hear about them after it is too late!)
• Look for useful vulnerability resources for particular projects you use. (For example, for WordPress, the recently launched WPScan Vulnerability Database.)

Over the past few years, I have ended up coming into contact with many computers belonging to individuals. My reason for doing so has varied, but usually I am helping them with something unrelated to security.

I found myself constantly saying the same things when I noticed bad security practices — “you really should update or remove Java”, “you need to actually stop clicking ‘Postpone’ and restart the computer some time”, “untick that box to install the toolbar” and so on.

Computer security is hard.

But, particularly when it comes to computers belonging to individuals, we have let the perfect become the enemy of the good. We have allowed anti-virus vendors to parrot messages about “total protection” instead of teaching sound principles and encouraging good practice.

Computer security, at least in this context, is in large part a human problem, not a technology problem.

So, a while ago, I had an idea to put together a really quick, 5-minute presentation that would encourage computer security principles that could dramatically lower the risk of individuals’ machines getting infected. I stripped it down to what I saw as the four most important principles (few enough that they might actually be remembered!):

1. Keep software up-to-date — with emphasis on the importance of updates, despite the inconvenience, and mention the high-risk software titles du jour whose updates may not be entirely hands-off (Flash, Java, etc.).
2. Keep up-to-date antivirus — with emphasis on such technology as the last line of defence, not ever a solution in and of itself.
3. Install software from trusted sources — perhaps the most important principle that requires behaviour change, this is about getting people to feel confident enough to build a trust model for software and then make informed decisions about each and every installation they make.
4. Be suspicious — in particular about communications that invite clicking on things and so on, including using alternative channels to verify legitimacy of things that look suspicious (e.g. never clicking unexplained links!)

I’ve not given this talk yet, but I’d like to. It feels that computer security on home PCs is, in general, so awful, that even a very basic set of ideas that are memorable enough to implement can probably make a significant difference to the health of our personal information infrastructure.

I would welcome feedback from others on these slides, as well as the idea.

I think it is quite important to keep it to five minutes, make it concise enough that it will be memorable and actionable, but I’m sure this idea can (and needs to) evolve and improve over time.

If you would like to use the slides, feel free to do so under the Creative Commons BY-NC-SA 2.0 licence. It would be great if many people could hear this message.

XDebug to the rescue…

My friend Niall Brady dropped me an email, saying that some of the users of his Windows-Noob forums were reporting getting redirected to a spammy-looking site (url4short dot info) when clicking on search results to the site.

The forums run the Invision Power Board (IP.Board) software. There had been some reports of vBulletin boards being hit with this kind of spammy redirect, but fewer suggestions that this was an IPB problem. There had been a patch for a critical IPB issue released in December, but that had, obviously, been applied to the site as part of normal good practice.

Nevertheless, I was concerned. Clicking on a search engine result should definitely not be redirect somewhere other than the result page!

Without evidence that the issue was not limited to one machine, or one connection, however, it could not be ruled out that it was just malware on that visitor’s machine.

» Read the rest of this post…

I read this BBC News story about mistakenly issued security certificates recently, which allowed the people with those certificates to impersonate any Google websites and intercept traffic to them. It struck me as quite significant that this particular story made it to &#8216mainstream’ tech reporting.

There is a more detailed, and perhaps more accurate, commentary on this attack on Freedom to Tinker. It perhaps may not have been ‘cyber criminals’ as the BBC reported it when I first viewed the story!

Anyway, given the attention to this issue, I thought it a good opportunity to review this kind of attack against SSL/TLS — the security system upon which we all now depend. More importantly, I wanted to show Certificate Patrol, an add-on for Firefox that would allow you to notice a suspicious change to an certificate and thwart this kind of attack.

The weaknesses inherent in having too many organisations that are able to issue security certificates for any domain are becoming more clear. While this kind of attack is extremely rare, at the moment, ‘at the moment’ is a very poor security response! Hopefully, more awareness of these limitations of the internet’s authentication infrastructure can help put pressure on browser vendors, website owners and CAs to make everyone more secure.

The security landscape for Mac OS X is changing. It has been for some time, but every now and then, an event comes along that highlights it.

I am thoroughly disappointed with how tardy Apple can be with releasing security updates. Java has been one of the components most visibly neglected in terms of timely patches. The recent ‘Flashback’ trojan for OS X exploited old, well-known vulnerabilities in Java that Apple had failed to promptly patch.

Java on Lion is deprecated, and is no longer installed by default. However, some upgrades from Snow Leopard bring Java along with them, and some users have manually installed Java for compatibility with certain applications.

If you do not know that you need Java installed on your system, do not install it. That is the best way to mitigate any security threat that would try to leverage a Java vulnerability to get into your system.

On Lion, however, once Java is installed, it does not seem to be possible to completely remove it.

What you can do is change the permissions on the relevant files so that it is ‘neutered’ and cannot run at all.

How to Completely Disable Java for Lion

I don᾿t recommend you disable Java on Snow Leopard. It is part of the operating system there, not an optional add-on component. I have not tried this process on Snow Leopard. Proceed to disable Java like this at your own risk (even on Lion)!

While logged in as an administrator user, open Terminal from Applications > Utilities.

Type the following commands in, pressing Enter after each one. You might be asked for your password.

sudo chmod 000 /System/Library/Java/JavaVirtualMachines/
sudo chmod 000 /Library/Java/JavaVirtualMachines

What these commands do is change the permissions mode to 000 on these Java files, meaning that no users have any permissions to even enter these folders, let alone read any files in them. This stops Java from running.

You can test that it is working, or, rather, not working, by now attempting to load Java Preferences in Applications > Utilities. You should be told that Java is not installed, and invited to install it. Click Not Now.

Re-enabling Java

If you suddenly find that actually you do need Java again, simply run the same commands in Terminal, but with the permissions mode 755 (the folder’s owner can read, write, and enter the directory, and everyone else can just read and enter the directory).

sudo chmod 755 System/Library/Java/JavaVirtualMachines/
sudo chmod 755 /Library/Java/JavaVirtualMachines

It should spring back into life!

Infected?

If you were unfortunate enough to be infected by Flashback (even if you did not type the Administrator password when it prompted), F-Secure has some instructions on its detection and removal. (Hat tip to @bldngnerd.)

I just came across an interesting post on the ESET Threat Blog (ESET being the antivirus vendor who are responsible for NOD32) about smartphone apps and the risk they potentially pose in a world when we install all sorts of applications, including those that deal with important and sensitive information, on the same device.

In particular, General Hayden remarks that ‘In the popular culture, the availability of 10,000 applications for my smart phone is viewed as an unalloyed good. It is not — since each represents a potential vulnerability. But if we want to shift the popular culture, we need a broader flow of information to corporations and individuals to educate them on the threat. To do that we need to recalibrate what is truly secret.’

Yes, each app that you install on your smartphone is a potential vulnerability. It is precisely for that reason you should be making decisions about what you installed based upon rational thought processes. There are some things that the reward is not great enough to warrant the amount of risk taken. For example, you might choose not to drive 120 MPH (193 KPH) because the cost of potentially getting isn’t worth the benefit of arriving sooner, or perhaps even the benefit of the fun of driving so fast. If you do choose to drive that fast where it is not permitted, and you do get caught, you may discover that the consequences are so extreme you wish you hadn’t have taken the chance.

When it comes to installing software on your smartphone, take a good look at what you may be risking. Do you do online banking or shopping with your smartphone? Do you have business contacts? Contact for friends? How about access to an email account with private emails? All of the information may be compromised if the wrong app is installed. After you identify what assets you have and their value, then consider the app you are installing. What is the benefit it poses to you? Is it worth potentially risking your information for a funny picture or a game you might play a couple of times a year and can probably play online, rather than installing it on your smartphone?

It’s an interesting read — and should remind everyone using an app-capable mobile device that it is a powerful computer, and with that comes a certain degree of risk. While the major smartphone software platforms have a higher level of technical separation between apps running on the same device than you typically get with a desktop PC, we should still be thinking about what apps are sharing ‘the floor’ with others, especially those which deal with more sensitive information, like mobile banking.

‘at risk’, by booleansplit / Robert S. Donovan on Flickr

Scott Charney of Microsoft’s ‘Trustworthy Computing’ effort wrote a blog post recently discussing the threats presented by botnets and other malware installed on users machines, where the user is unaware of or apathetic about the presence of that software.

Just as when an individual who is not vaccinated puts others’ health at risk, computers that are not protected or have been compromised with a bot put others at risk and pose a greater threat to society. In the physical world, international, national, and local health organizations identify, track and control the spread of disease which can include, where necessary, quarantining people to avoid the infection of others. Simply put, we need to improve and maintain the health of consumer devices connected to the Internet in order to avoid greater societal risk. To realize this vision, there are steps that can be taken by governments, the IT industry, Internet access providers, users and others to evaluate the health of consumer devices before granting them unfettered access to the Internet or other critical resources.

I have argued previously against the “there’s nothing important on my computer, so I don’t care” response that some have to the discovery of malware on their machines, and I certainly believe that it is an irresponsible attitude that contributes to these greater threats.

But I am concerned about some of the solutions which Scott proposes — particularly those that might seek to create legislation and obligations on individual computer users.

» Read the rest of this post…

The first worm to infect the Apple iPhone has been discovered spreading ‘in the wild’ in Australia.
The self-propagating program changes the phone’s wallpaper to a picture of 80s singer Rick Astley with the message ‘ikee is never going to give you up’.
The worm, known as ikee, only affects ‘jail-broken’ phones, where a user has removed Apple’s protection mechanisms to allow the phone to run any software.

The news of this worm is likely to attract the attention of some anti-Apple and anti-iPhone crowds and used as an argument as to why the iPhone isn’t secure, and Apple people should no longer feel safe and so on and so on.

To those who would seek to lose a sense of perspective on this story:

This worm works only on jailbroken iPhones (an unsupported procedure), where the user did not change the default root password and left the remote login SSH service running.

This attack says nothing about the security of the iPhone software — it exploits little more than very poor configuration on the user’s part. If you choose to jailbreak your device, you have a responsibility to understand the implications that has. Which means, change the damn root password to something other than ‘alpine’. While you’re at it, also change the password for the user mobile too.

Despite having defended the iPhone thus far, I’m not in the business of assuming Apple get every aspect of security right all the time and I’m not in the business of declaring the Mac or the iPhone to be ιsecure’, or more secure than anything else. As hope I made clear in my previous post, a simplistic black-and-white approach to looking at computer security doesn’t make any sense or do anyone any favours.

I’m not complacent about security because I use a Mac*. I am confident because I feel I have grasped a good understanding of the risks and of trust.

* or Linux, or anything that I perceive as being more secure.

Secure. by Wysz on Flickr

I can’t stand the attitude of “there’s nothing important on my computer, so I don’t care about whether it is secure or not”. The simple fact of the matter is that any infected computer connected to the internet is probably at the mercy of a malicious third party. Even if you don’t care about the impact of your computer being infected, your lazy attitude is affecting innocent other people’s computers, potentially in the form of sending mass spam and attacking unwitting websites.

Computer security is hard and very complex.

How we explain computer security and insecurity to average computer users, non-geeks if you will, is really important. And I really think that we are taking the wrong approach at the moment.

We teach computer users that in order to keep their computer secure and clean, they must have:

• An anti-virus program
• A firewall
• Up-to-date software
• … and other practical, simple steps

While these are all very important steps to encourage (especially keeping software up-to-date, in my mind), I think that we are making this advice a bit too practical. We’re ignoring complexity and only ever offering the most basic practical steps.

In my mind, a lot of computer security comes down to a model of trust. For example, I feel confident that a conversation with my internet bank is secure because:

• I trust the integrity of the SSL connection for the purposes of keeping my information private and untampered with as it goes across the internet
• I trust my local machine to be ‘clean’
• I trust the remote machine at the bank is genuine and set up properly

All three of those things must be in place for me to have that ‘safe’ feeling. A safe SSL connection to your bank is meaningless if there’s nasty software on your local machine sending your keystrokes to a third party.

I’d like to see this model of trust be encouraged amongst all computer users. It maybe does take a little bit more time and effort to understand the basic principles of what is going on, but looking at security this way round, rather than from an entirely practical viewpoint, allows people to make informed security decisions, rather than blindly trusting some ‘security’ software to do everything.

Social engineering is a very easy way to get some nasty inside someone’s computer. It’s disappointing, but oftentimes you can trick the human into deliberately giving permission to something more easily than you can find a hole in software to do the same thing. Instead of relying on ‘last resort’ antivirus programs to catch known malicious programs running at the last minute, we should encourage people to ask questions:

• Why am I being asked to run this software?
• Where did it come from? Do I trust the group of people that wrote this program?
• Is there anything suspicious or unusual about this? Is it really coming from who it says it is?

Obviously, you need to combine this with practical advice and some knowledge to enable people to spot things that are ‘out of place’. But I think if we did, people would be in a much better position to make sensible informed decisions and to understand better what is actually going on.

This rant only really covers one aspect of computer security. As I said at the start, computer security is really complex and really hard to get right. So this approach isn’t necessarily the answer and it isn’t going to be applicable everywhere. There are going to be groups of people for whom this will be too complex, and groups of people that ‘won’t care’. But I’d like to see it done more often.

Photo is Secure. by Wysz from Flickr. Licensed under Creative Commons BY-NC.