Category Archives: Malware

Ransomware update

A typical ransomware alert screen. Not something you ever want to see on your computer.

The scourge of ransomware shows no signs of slowing down. A single careless click on a link in an email is all that’s necessary for one of the many varieties of ransomware to install itself and quietly start encrypting data files on your computer, and on any others it can reach. Warning screens like the one above announce the dreadful news: your files are now effectively garbage. Pay the ransom or you’ll never see those files (intact) again.

Reports of ransomware hitting schools and hospitals are depressingly common. There’s evidence that attacks on sensitive targets like hospitals are intentional. Ransomware is now being installed by trojan malware that previously only stole your banking information. Newer televisions and other ‘smart’ devices that are connected to the Internet are being hit with ransomware that limits their functionality. Phony ICANN blacklist removal email is being used to trick people into installing ransomware.

If you’re wondering just how deep this ugliness goes, consider this: at least one strain of ransomware offers to decrypt your files for free if you pass the malware along to at least two other computers.

Assuming you’ve managed to avoid this nightmare, you’re either using strong anti-malware software, or you’ve trained yourself not to indiscriminately click links on the web and in email (hopefully both). Otherwise, you’re probably just lucky. So far, my only encounter with ransomware was a partial infestation of a client PC; the malware was prevented from doing any real damage by antivirus software (Trend Micro’s Worry-Free Business Security for anyone wondering).

Okay, so what’s the good news? Companies like No More Ransom offer services that can (sometimes) reverse the damage caused by ransomware. Of course, the success of this kind of service depends on the type of ransomware; some strains are easier to work around than others. But at least there’s hope for those ransomed files.

Brian Krebs investigation reveals author of Mirai worm

The Mirai worm has compromised thousands of IoT devices that were subsequently used in several recent, massive DDoS attacks, including one against the web site of Brian Krebs, well-known security researcher and blogger.

In an appropriately-lengthy post, Krebs describes the process by which he tracked down the identity of the author of the Mirai worm. It’s a fascinating read.

Krebs has published the results of similar investigations in the past, which is why he’s become a target for DDoS attacks, Swatting, and other despicable acts. It remains to be seen whether he will be the target of any new attacks in the wake of his Mirai investigation.

I applaud Krebs’ persistence and dedication in the face of these attacks. Here’s hoping he keeps fighting the good fight, for the benefit of Internet users everywhere.

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).

DDoS attacks on Dyn caused outages and slowdowns

If you use Twitter, reddit, Amazon, Tumblr, Spotify or Netflix, you may have noticed that they were slower than usual for parts of yesterday. That’s because the affected sites and services use Dyn, a DNS service provider, and Dyn was hit by two huge DDoS attacks yesterday.

The attacks lasted for a few hours, and while they certainly affected a lot of people, they were no more than an inconvenience for most. Still, the surge in the number and size of these attacks is troubling.

Analysis of the attacks shows that they were made possible by the Mirai botnet, which uses a huge network of poorly-secured (and now compromised) DVRs and security cameras. Those are the same tools used in the recent krebsonsecurity.com and OVH DDoS attacks. The source code for Mirai was released to the public recently, which means just about anyone could have caused the Dyn attacks.

Brian Krebs has more.

Update 2016Oct24: Dyn has released a statement about the attack on their systems, in which they clarify the timeline, and confirm that the Mirai botnet was involved. Meanwhile, security expert Bruce Schneier doesn’t believe that the recent attacks were perpetrated by a state actor such as China. He also doesn’t think they were related to the probing attacks he reported earlier. But he is concerned that the attacks will continue to grow in size and frequency, because nobody involved is motivated to fix the problem.

Chinese device maker Hangzhou Xiongmai has issued a recall for several of its webcam models that were used in the attacks. However, they are only one company out of hundreds (maybe thousands?) of companies producing poorly-secured IoT devices.

Update 2016Oct25: According to Brian Krebs, Xiongmai has also made vague legal threats against anyone issuing ‘false statements’ about the company. This is presumably part of a PR effort to improve the company’s image in the wake of the attacks, but it’s hard to see how this will help anyone. The company’s main objections apparently relate to statements by Brian Krebs and others about users’ ability to change passwords. Testing has shown that back-door, unchangeable passwords exist on some of the affected devices.

Infosec highlights – October 5, 2016

Cryptocurrency-mining malware known as Mal/Miner-C is targeting specific Seagate Central Network Attached Storage (NAS) devices. The malware locates the devices when they’re exposed to the Internet and installs a special file in a public folder. Unwary users try to open the file, which installs the malware on their Windows computer. Once installed, the malware uses available resources to mine the Monero cryptocurrency. There are about 7000 of these devices globally.

It’s standard practice to tell users to lock their computers when they walk away from their desks. A locked computer presents an obstacle to anyone with physical access who’s interested in poking around or stealing data. But in reality, once someone has physical access to a computer, there are ways to gain full access, even when that computer is locked. Now there’s a new technique that simplifies this task. A specially set up thumb drive is inserted in the target computer (Mac or PC), and 20 seconds later, the intruder has valid login credentials in their hands.

Two Factor Authentication (2FA or MFA) is an increasingly-common way to bolster your security when using Internet-based services and web sites. It adds a second step to the login process, which usually involves entering a special code. Many sites and services that offer 2FA send codes to your registered cell phone via SMS text messages. Unfortunately, that specific method (codes via SMS) can be co-opted by attackers who already have your password (which is increasingly likely with all the recent breaches). If you’re using SMS text for 2FA, you should look into more secure methods. Google Authenticator generates temporary, time-limited codes using an app on your smartphone. Duo Security has an app that receives special ‘push’ messages from the site you’re trying to access, and all you have to do is click a button on your cell phone to get in.

Bruce Schneier wants everyone to stop blaming the user for security problems and create systems that are more inherently secure. As things are today, the user gets most of the blame when something goes wrong. Clearly, using weak passwords, re-using passwords, and generally being vulnerable to phishing and other manipulation point to the user as the weak link. But Schneier thinks pointing at the user isn’t helpful, especially when that link is unlikely to ever change. Instead, he wants to limit the involvement of the user; to create fewer security pitfalls. He points to current efforts along those lines, including automatic security updates, and virtualization. Which are both great ideas, as long as us techie folks have a way to bypass those things.

Recent Infosec highlights

It sometimes feels like news in the world of information security (infosec) is a never-ending tsunami. With the almost-daily reports of breaches, malware, phishing, vulnerabilities, exploits, zero-days, ransomware, and the Internet of Things (IoT), it can be difficult to identify stories that are likely to be of interest to typical computer users.

Stories about infosec issues that are primarily academic may be interesting, but they’re unlikely to affect most users. Sometimes the impact of a security issue is exaggerated. Occasionally the threat is later found to be nonexistent or the result of faulty reporting.

In the past, I collected infosec stories and wrote about the most interesting and relevant ones in a single month-end roundup. This helped to manage the load, but it introduced an arbitrary and unrealistic schedule.

Starting today, I will occasionally post a few selected infosec stories in a single ‘highlights’ article. Without further ado…

Don’t be a victim of your own curiosity

Researchers in Germany discovered that most people click phishing links in emails, even when they don’t know the sender, and even when they know they shouldn’t do it. Why? Curiosity, apparently. It doesn’t just kill cats any more.

Promising new anti-phishing technology

On a related note, there’s a new reason to be optimistic in the fight against phishing. A proof-of-concept, prototype DNS greylisting service called ‘Foghorn’ would prevent access to unknown domains for 24 hours, or until the domain is identified as legitimate and whitelisted. Hopefully Foghorn will prove effective, and become available for regular users in the near future.

Scope of 2012 breaches of Last.fm and Dropbox finally revealed

Popular Internet radio service Last.fm suffered a breach way back in 2012, but the details were not revealed until very recently. According to a report from LeakedSource, as many as 43 million user passwords were leaked, and the passwords were stored using very weak security. If you had a Last.fm account in 2012, you were probably instructed to change your password. If you didn’t do it then, you should do it now.

Massively popular file sharing service DropBox was also breached in 2012, but again, the complete details of the breach are only coming to light now: passwords for as many as 60 million Dropbox user accounts were stolen. The validity of this information has been verified by SANS and Troy Hunt.

The usual advice applies:

  • If you have accounts for these services, change your passwords now, if you haven’t already.
  • Avoid using the same password for more than one service or site.
  • Use complex passwords.
  • Use password management software so you don’t have to remember all those unique passwords.

SANS ‘Ouch!’ newsletter for August 2016

This month’s ‘Ouch!’ (PDF) is about Ransomware, that nasty type of malware that encrypts your data files and (if you’re lucky) allows for their decryption, once you pay a ransom.

It’s definitely a worthwhile read, especially if you’re not familiar with the term. Ransomware is real, and affecting increasing numbers of users.

Also see Ransomware update, recently posted on this site.

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.