Category Archives: Spam and scams

About those troubling emails you’ve been getting…

If you have an email address, and you’ve ever used it to register for online services and sites, there’s a good chance you’ve received email that threatens you in some way, and some of it is downright creepy.

This email may refer to your name. It may include a password you’ve used in the past, or even currently. The email may appear to have been sent from your own email address, and may claim to have taken over that email account.

A sextortion email I received recently.

The good news is that very little of what these emails claim is actually true. The bad news is that you still have a problem.

But why does this happen?

It all starts when someone gets careless, or someone else decides that the IT budget is too high.

Imagine that you’re the person responsible for information security at any company that… uses computers (so basically, any company on the planet). Now imagine that you’re bad at your job. Or disgruntled. Or your manager keeps cutting your budget. Inevitably, things start to slide. Security updates don’t get installed. Software that isn’t properly checked for security implications gets installed on company computers. Users don’t get security training. Bad decisions are made, such as not properly encrypting user passwords. And so, the company’s computers, and the data they contain, become vulnerable. Eventually, malicious people figure this out, and through various means — many of which are trivially simple to carry out — gain access to your data. And that data includes information about your customers. That information is then sold online, to other, even less scrupulous people. Brian Krebs documents many of these breaches; here’s one example.

You can find these lists online if you know where to look. Some are only accessible from the dark web. Some are published more brazenly, on easily-accessed public web sites, including Facebook.

Sometimes these lists contain passwords. In really awful cases, the passwords aren’t even encrypted. But usually they are encrypted, which makes them slightly less useful. Only slightly, because many people still use terrible passwords: common passwords, like 1234; passwords that are used by the same person in multiple places; and passwords that are easy to crack.

Any password can be cracked, by which I mean converted from its encrypted form to its original, unencrypted form. Short and simple passwords can be cracked in nanoseconds. Longer, more complex passwords take longer. At any given point in time, passwords that are long and complex enough simply can’t be cracked quickly enough to be worth the attempt. This is a moving target. As computers get faster, the point at which a password becomes worth cracking gets nearer.

You can find out just how terrible your password is using howsecureismypassword.net. Note: the site is safe to use: it uses a small Javascript program that runs only on your computer. Your password is never transmitted anywhere. And it’s not actually being cracked; the Javascript code just assesses the complexity of your password based on various formulae. It’s an estimate, but reasonably accurate. Go ahead, I’ll wait.

Useful lists

These shady lists of users, passwords, and email addresses can be used for lots of things, ranging from merely irritating to criminal. But there’s money to be made, as long as you don’t care about being a world-class asshole.

If you’re an asshole, and you’re looking for an easy way to make money and irritate people, just shell out a few bucks for one of these lists, and download a few scripts that turn that list into spam. Because computers are really good at things like this, you hardly have to do any actual work. Just feed a list into some crappy script, sit back, and watch the money pour in. If you had to do this with paper and snail mail, it clearly would not be worthwile.

A user’s story

Let’s look at this another way: from the perspective of Iam Notreal, an ordinary Internet user. Iam registered for an account at LinkedIn in 2011 using his real name and his NopeMail account, iam.notreal@nopemail.com. He also used the same password he uses everywhere else: banana1234.

In 2012, intruders gained access to LinkedIn servers and were able to download its user database. The database included usernames, email addresses, and poorly-encrypted passwords. Now Iam’s real name, real email address, and an encrypted form of his one and only password are on a list, and, beginning in 2016, that list is being sold on the dark web to anyone who has a few bucks to spare.

In 2016, Iam starts getting spam to his NopeMail account. Most of it is ordinary spam: poorly-worded appeals to click a link. Occasionally he receives spam that mentions his real name, which is alarming, but not particularly harmful. At some point, Bill tries to ‘unsubscribe’ from what he believes is a mailing list, by replying to one of these spam emails. Congratulations, Iam, you’ve just graduated to a new list, of confirmed, valid, active email addresses. This list will also be sold on the dark web, at a higher price than the original list.

Meanwhile, other dark forces are at work behind the scenes. Someone runs the original list through a widely-available password cracker. This software looks at each encrypted password and attempts to decrypt it based on a set of parameters, including lists of commonly-used passwords. Sadly, Iam’s password is rather short, and contains a common word, and it takes the software about a nanosecond to crack it. Now Iam is on an even more valuable list, which includes cracked passwords.

Fast forward to 2018, and now Iam is getting email that claims to have taken over his email account, or to have video from Iam’s own webcam showing him doing unmentionable things, and it also includes Iam’s one and only password, right there in plain text. Iam is panicked: if the sender knows his password, are the rest of the claims true? He doesn’t know it, but the sender’s claims are bullshit.

As scary as this sounds, it’s only the most common use of lists like these circa late 2018, early 2019. The same information could be used to take over Iam’s LinkedIn account (if he ignored warnings from LinkedIn to change his password, or if he changed it back to the same password), take over his NopeMail account (if he failed to change its password after the LinkedIn breach), or take over any other account that can be found on any other service he uses, once it’s discovered.

Questions

Why is that spam coming from my own email address or my own mail server?

Unfortunately, it remains trvially easy to spoof almost all information contained in an email message. Current anti-spam efforts like SPF, DKIM, and DMARC are focused on validation, and there’s nothing stopping anyone from spewing out email with mostly-forged headers. That includes the FROM header, which means scammers can make email look like it came from just about any address they want. Only close inspection of all the headers reveals the actual source.

Why does that spam contain my password?

If a scammer has access to a purloined user list that includes plaintext or cracked passwords, it’s a simple matter of customizing the content of their malicious spam so that the username and/or password vary, depending on the unlucky recipient.

What you should do

Stop using crappy passwords. If you’re not sure how crappy your password is, check it at howsecureismypassword.net. You can also install this extension in your Chrome browser; it will warn you if your password is too weak.

Stop re-using passwords. If site A is hacked, and your password for site A is the same as for site B, you’ll have to change your password on both sites.

Use a password manager. Yes, it’s annoying to have an extra step whenever you want to log in somewhere, but using a password manager means that you only ever have to remember one password. They can also generate passwords for you, saving you the trouble.

Check Have I been pwned to see how many breaches have included your email addresses and passwords.

Sign up at Spycloud to continuously monitor your email address for inclusion in breaches.

Making noise

Although there are ways to use purloined user lists besides spam, most of the damage we see is related to email.

Despite being really old technology, email has continually improved in terms of security. Newer technologies like SPF, DKIM, and DMARC make it much easier for email providers to determine which email is legitimate and which is not.

You can help by making sure any email domains you manage use SPF, DKIM, and DMARC. If your mail provider doesn’t use these technologies, lean on them to start. If they resist, find another provider. I have several clients who use the business mail service provided by telecom giant Telus here in Canada. Telus farms this work out to a provider in the USA called Megamailservers. The Megamailservers service does not currently support DKIM or DMARC, and there’s nothing on their web site (or that of Telus) about any plans to change that.

Password Management Software

So, everyone should use a password manager. But wait, didn’t I just read that all the most popular password managers can be bypassed very easily? Yup. Opinions vary as to whether the risk of such exploits is significant. From my perspective, the risk is this: yes, a malicious actor needs physical, remote, or programmatic access to your computer to use these exploits. But once they have access, they no longer have to waste time looking for interesting information. All they need to do is look for password manager data and sent it to themselves. That makes their job MUCH easier.

But using a password manager is still much safer than not using one.

References

How to spot phone call scams

Have you been getting a lot of scam phone calls lately? I sure have. On both the land line and my business cell phone. Some callers claim that I’m being sued by the government or that I’m under investigation. Others want me to think there’s something wrong with my computer and that they have the only fix.

I’m pretty good at spotting these scams, and for me, they’re sometimes entertaining, but usually just annoying. For some people, especially elderly folks with little technical knowledge, these calls can be a horrible trap.

The latest edition of the SANS OUCH! Newsletter is all about phone scams: how to spot them, and what to do when you receive them.

Recommended: My Online Security web site

My Online SecurityEver wondered what would happen if you did the unthinkable and clicked the link in that suspicious-looking email? Well, wonder no more, because there’s a guy in the UK who analyzes all the malware, viruses, scams, and phishing email he receives, and publishes his findings on his web site, My Online Security.

The site operator is in the UK, so he may not always be exposed to the same threats as those of us in North America, but I’ve found that there’s a lot of overlap. Usually, if I’m seeing a particular kind of scammy email, this guy has written about it. The site is updated frequently, often multiple times per day.

There are other useful resources on My Online Security, including a malware submission form, links to other malware analysis sites, a support forum, and recommendations for staying safe online.

Google gets tougher on scammy web sites

If you use Google search (and really, who doesn’t?), you’ve probably noticed the big warnings that appear when you try to click on some search results. That’s Google Safe Browsing (GSB), protecting you from a malicious web site.

GSB flags sites that fail to comply with Google’s Malware, Unwanted Software, Phishing, and Social Engineering Policies.

To get rid of the warning, the owner of a site flagged by GSB must remove objectionable content and resubmit the site for verification in Google Search Console. Until recently, this process could be repeated indefinitely.

To counter repeat offenders, Google has changed the way GSB works. If a web site repeatedly fails to comply with Google’s Safe Browsing policies, it will be flagged as such, and the warning users see will appear for at least 30 days.

In the announcement for this change, Google points out that the new repeat offender policy will not apply to sites that have been hacked (i.e. changed without the owner’s permission).

Ransomware update

Ransomware has been in the news a lot lately. The CryptXXX ransomware is no longer susceptible to easy decryption, and it’s been making a lot of money for its purveryors, in many cases using compromised, high profile business web sites as its delivery mechanism. On a more positive note, the people who created the TeslaCrypt ransomware stopped production and released global decryption keys. New ransomware delivery systems are able to bypass Microsoft’s EMET security software. The Cerber ransomware was recently delivered to a large proportion of Office 365 users via a Word document in an email attachment. And an even more hideous piece of malware surfaced in the last week: posing as ransomware, Ranscam actually just deletes all your files.

Ransomware is different from other kinds of attacks because of the potential damage. It can render all your data permanently inaccessible. Even paying the ransom is no guarantee that you will get all your data back intact. Other types of attacks typically try to fly more under the radar: trojans and rootkits want to control and use your computer’s resources; and viruses want to spread and open the door for other attacks. While other types of attacks can be fixed by removing the affected files, that doesn’t work for ransomware.

Like other types of attacks, ransomware first has to get onto your computer. These days, simply visiting the wrong web site can accomplish that. More common vectors are downloaded media and software, and email attachments. Preventing malware of any kind from getting onto your computer involves the kind of caution we’ve been advising for years; ransomware doesn’t change that advice.

What CAN make a big difference with a ransomware attack is limiting its reach. Once on a computer, ransomware will encrypt all data files it can access; specifically, files to which it has write access. Ransomware typically runs with the same permissions as the user who unwittingly installed it, but more insidious installs may use various techniques to increase its permissions. In any case, limiting access is the best safeguard. For example, set up your regular user so that it cannot install software or make changes to backup data.

Here’s a worst-case scenario: you run a small LAN with three computers. All your data is on those computers. Your backup data is on an external hard drive connected to one of those computers, and a copy exists on the Cloud. For convenience, you’ve configured the computers so that you can copy files between them without having to authenticate. Once ransomware gets onto one of the computers, it will encrypt all data files on that computer, but it will also encrypt data it finds on the other computers, and on the external backup drive. Worse still, some ransomware will also figure out how to get to your cloud backup and encrypt the data there as well.

How to limit your exposure? Require full authentication to access computers on your LAN. Use strong, unique passwords for all services. Store your passwords in a secure password database. Limit access to your backup resources to a special user that isn’t used for other things. In other words, exercise caution to avoid getting infected, but in case you get infected anyway, make sure that you have walls in place that limit the reach of the ransomware.

Most ransomware targets Windows systems, so most of the verbiage out there is about Windows as well. This article covers the basics fairly well.

April security roundup

People who store Slack credentials in Github code repositories learned that this a bad idea, as researchers demonstrated the ease with which this information can be gathered without any explicit permissions.

Scary news: computers at a German nuclear reactor facility were found to be loaded with malware. The only thing that prevented miscreants from playing with real nuclear reactors was the fact that these computers are not connected to the Internet.

Crappy security practices led to the theft of user account information (email addresses and poorly-encrypted passwords) from Minecraft community site Lifeboat.

The notorious hacking group known as Hacking Team made the news again, this time with reports of active drive-by exploits affecting Android devices.

The Nuclear exploit kit is still operating, despite recent, partially-successful, efforts to shut it down. Researchers showed that the kit is still being used, and may be involved in recent ransomware infections.

Good news: the two men responsible for the notorious SpyEye banking trojan, recently extradited to the US to face federal prosecution, will be spending nine and fifteen years in prison.

Zero-day exploits are on the rise, doubling from 24 in 2014 to 54 in 2015. A zero-day exploit is a hack that takes advantage of software vulnerabilities before the software’s maintainers have had a chance to develop a fix.

Cisco security researchers identified vulnerabilities in several enterprise software systems, including Red Hat’s JBoss. As many as three million web-facing servers running this software are at risk of being infected with ransomware, and in fact as many as 2100 infected servers were identified.

More good news: the Petya ransomware was found to contain a flaw that allows its victims to decrypt their data without paying any ransom.

The Mumblehard botnet was taken down by ESet researchers, after it infected at least 4000 computers and sent out countless spam emails.

Microsoft announced plans to prevent Flash content from playing automatically in the Windows 10 web browser Edge. All the major browsers appear to be heading in this direction, if they don’t already have the feature, as does Chrome.

April’s issue of the SANS ‘Ouch!’ newsletter is titled “I’m Hacked, Now What?” (PDF) and provides helpful information for the recently-hacked. The newsletter is aimed at regular users, so it may not be particularly useful for IT professionals, except as a means to educate users.

The wildly popular WhatsApp – a messaging application for mobile devices – now has end-to-end encryption. This will make life more difficult for spy agencies who want to know what users are saying to each other. But WhatsApp users should be aware that this does not make their communications invulnerable, since techniques exist to get around full encryption, such as keystroke loggers.

Bad idea: someone at CNBC thought it would be a good idea to ask users to submit their passwords to a web-based system that would test the passwords and report on their relative strength. The service itself was vulnerable, and exposed submitted passwords to network sniffing. The service was taken offline soon after the vulnerability was identified.

The web site for toy maker Maisto International was hacked and serving up ransomware for an unknown amount of time, probably several days or even weeks. The hack was made possible because the site was using outdated Joomla software.

Security roundup for March 2016

Ransomware made news frequently in March. Two more healthcare networks in the USA were hit with ransomware. A new variety of ransomware called Petya took things to a new level, encrypting the core data structures of hard drives. TeslaCrypt continued its destructive march across Europe and into the USA. A surge in malware-laden advertising (aka malvertising) on several popular web sites, including the Certified Ethical Hacker site, led to numerous ransomware infections.

Smartphones and tablets running Google’s Android operating system remain a popular target for malware. A newly-discovered vulnerability can allow malware to permanently take over a device at the root level. Malware that exploits the still largely unpatched Stagefright vulnerability was identified.

Security researchers discovered malware that can infect computers that are not connected to networks, using external USB devices like thumb drives. The malware, dubbed USB Thief, steals large quantities of data and leaves very little evidence of its presence.

A hacking group known as Suckfly is using stolen security certificates to bypass code signing mechanisms, allowing them to distribute malware-laden apps more effectively.

The folks at Duo Security published an interesting post that aims to demystify malware attacks, describing malware infrastructure and explaining how malware spreads.

Ars Technica reported on the surprising resurgence of Office macro malware. Macros embedded in Office (Word, Excel) documents were a major problem in the 1990s but subsequent security improvements by Microsoft reduced their prevalence until recently. Getting around those improvements only requires tricking the document’s recipient into enabling macros, and it turns out that this is surprisingly easy.

Millions of customer records were made available in the wake of yet another major security breach, this time at Verizon.

Google continued to improve the security of its products, with more encryption, better user notifications and other enhancements to GMail.

Brian Krebs reported on spammers taking advantage of the trust users have in ‘.gov’ domains to redirect unsuspecting users to their spammy offerings.

Opera announced that their web browser will now include ad-blocking features that are enabled by default.

July security roundup

Flash improvements

Adobe is trying desperately to keep Flash viable. In July, they announced structural changes that are expected to strengthen Flash’s overall security. The changes are so far only available in the most recent versions of Chrome, but they are expected to find their way into the other major browsers in August.

Asprox botnet status

There’s an interesting (though technical) overview of recent changes in the behaviour of the Asprox botnet over on the SANS Handler’s Diary. Apparently the botnet is no longer sending malware attachments, and is instead sending pornography and diet-related spam. Comparing my inbox contents with the samples in the linked article, it looks like most of the spam I currently receive is thanks to Asprox. Hopefully Asprox will be targeted by the anti-botnet heavy hitters in the near future.

Flaw in BIND could cause widespread issues

BIND is one of the most common pieces of software on Internet-facing servers. It translates human-readable addresses like ‘boot13.com’ into IP addresses. A bug in version 9 of BIND causes it to crash when a specially-crafted packet is sent to it. Attackers could exploit this bug to execute an effective Denial of Service (DoS) attack against a server running BIND9. Patches have been created and distributed, but any remaining unpatched servers are likely to be identified and attacked in the coming months. Update 2015Aug05: As expected, this bug is now being actively exploited.

Mobile versions of IE are vulnerable

Current, patched versions of Internet Explorer running on mobile devices were recently reported to have four flaws that could allow attackers to run code remotely. Exploits were published, although none have yet been seen in the wild. The vulnerabilities were disclosed by the HP/TippingPoint researchers who discovered them, six months after they privately reported them to Microsoft. Microsoft has yet to patch these vulnerabilities; they apparently feel that vulnerabilities are too difficult to exploit for them to be dangerous.

Stagefright vulnerability on Android devices

A flaw in Stagefright, a core Android software library that processes certain types of media, makes almost all Android phones and tablets vulnerable. The flaw can be exploited as easily as sending a specially-crafted text (MMS) message to a phone, but also by tricking the user into visiting a specific web site. Successful attackers can then access user data and execute code remotely. Unfortunately for users, it’s up to individual manufacturers to develop and provide patches, and this process may take months in some cases. There’s not much users can do to mitigate this problem until patches arrive. Update 2015Aug05: Google is working with its partners to push updates to affected mobile devices.

Mediaserver vulnerability on Android devices

More bad news for Android users: the mediaserver service apparently has difficulty processing MKV media files, and can render a device unusable when it encounters one on a malicious web site. In most cases, the device can be brought back to life by powering it down and back up again.

Android spyware toolkit widely available

And the hits just keep on coming for Android devices. Among the information revealed in the recent Hacking Team breach was the source code for an advanced Android spyware toolkit called RCSAndroid. Like everything else taken from Hacking Team’s systems, this has now been published, and no doubt malicious persons are working on ways to use the toolkit. There’s no easy way to protect yourself from this toolkit, aside from keeping your device up to date with patches. From Trend Micro: “Mobile users are called on to be on top of this news and be on guard for signs of monitoring. Some indicators may come in the form of peculiar behavior such as unexpected rebooting, finding unfamiliar apps installed, or instant messaging apps suddenly freezing.

Avoid Hola’s free VPN service

In the wake of Snowden’s revelations, many people have started using VPN services to encrypt their online activities. Until recently, one popular choice was Hola’s free VPN.

Researchers have discovered that Hola is selling access to the resources of its users, creating what has been described as a botnet, which may have been used for malicious activities.

Hola has been scrambling to deal with the public backlash over this news, but so far all they’ve done is retroactively update their FAQ, adding statements about what Hola can do with your computer if you’ve installed their software.

Recommendation: avoid Hola completely. This kind of deceptive behaviour should not be encouraged. If you’ve been using Hola, check your level of exposure using this handy tool.

Test your skill: spot the phishing email

A short quiz, provided by anti-malware software maker McAfee, allows you to test your skill at identifying phishing email.

In the quiz, you are presented with ten email samples, and asked to decide whether they are phishing email.

What is phishing? From Wikipedia: “Phishing is the illegal attempt to acquire sensitive information such as usernames, passwords, and credit card details (and sometimes, indirectly, money), often for malicious reasons, by masquerading as a trustworthy entity in an electronic communication.

Hint: look for links in each of the sample messages. Hover your mouse over each link, and compare the address with the supposed sender. If a link points to a site that’s unrelated to the supposed sender, the email is probably not legitimate.

Hat tip to reader tap tap.