Ransomware! What is it, and what can I do about it? (Part 2 of 2)

April 10, 2017 at 4:55 pm | Posted in cybersecurity, Knowledge | Leave a comment
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In my first post (Part 1), I went over the basics of how ransomware exploits your computer, and the #1 weird trick that computer experts use to avoid the pain of ransomware: namely, always have a current, offline backup of your files where the thieves can’t encrypt it in the first place.  Backups can save you from the pain, the agony, and the grief of ransomware. You may have to reimage your computer and copy a known set of good files from a backup set, so the more often you back up, the better off you’ll be.

However, if everyone always had a current backup, there’d be a lot less ransomware out there. The criminals who spread ransomware know that most people don’t back up their data. According to the FBI, attacks by ransomware accrued over $18 million by June 2015, and ransomware attacks are expected to boom in 2017. Crime pays, and pays well.

GGordonLiddy

Also, cybercriminals attack new and surprising venues every day (like Android screen lockers that demand payment in Amazon gift cards), so you may be the next victim. And while backups are good, you don’t want ransomware (or malware of any kind) on your computers in the first place.  And finally, if you’re in IT, you’re always going to field the eventual call from your mom, your brother, or your college roommate, saying “Help! There’s a message on my computer screen that says ransomware has infected my router and I have to pay $200!”

In this post, I’ll go over some general suggested practices to harden the various areas of your computer or network where malware might enter in the first place. I’ll also list the better resources to turn to for ransomware news and solutions that may help you extricate someone from a ransomware attack.

(Note: the first part is mostly Windows-based, but the second part applies to all computer users.)

Reveal it all

If you run a Windows machine, you should always show hidden file extensions using Windows Explorer. The average user – your college roommate, Joe Lunchbucket – has been warned a zillion times by the IT department never to open an executable file from email or a URL, and believe it or not, he won’t. But if he unzips an attachment, say an automated email from the local printer, and sees a file named BillJones_Resume.PDF, he’s going to think it’s really a PDF file. If file extensions are hidden (the default behavior) he won’t realize the file is actually BillJones_Resume.PDF.exe.

File extension viewing can be enabled by opening Windows Explorer, choosing the View, choose Options, and choosing Change folders and search options. On the View tab of the Folder Options window, uncheck Hide extensions for known file types. (The exact path may depend on which version of Windows you run.)

FolderOptions

Keep executables and known bad links out of email, and keep updates current

Ensure that your email service filters out EXE and script files. This may not protect you from someone hiding an EXE in a ZIP file, though. At work, your corporate infrastructure should have in-mail protection such as antivirus engines that check mail and attachments before the email is sent to the inbox, and checks web links to see if they are dangerous or spoofed.

If you’re operating in a Windows enterprise environment, you or your IT administrator can use Group Policy Objects (GPO) to prevent ransomware like Cryptolocker from executing its payload in the \USERS folder, AppData, Local App Data folders, or Temp directories.

Check if you have any Remote Desktop Protocol (RDP) ports open and disable these ports to prevent access to your desktop remotely. (TrendMicro reported a sharp uptick in the number of brute-force RDP attacks in 2016.)

Patch or update your software and browsers regularly. Windows Update ensures that you have security patches and fixes for your operating system. Remember, if you have Windows 10, your free malware/anti-virus protection app is Windows Defender. To get updated malware and virus signatures, and to update Windows Firewall, you have to run Windows Update.

On a related note, make sure your device firmware (even routers, streaming devices and smart TVs, and refrigerators) are updated regularly.

Axe the non-essentials and known vulnerabilities

Remove Adobe Flash on computer. Do you need Adobe Flash? Lots of malware attacks come from fake pop-ups that tell the user to update their Adobe Flash or from malvertising that uses Flash. If you do keep Adobe Flash, make sure that your antivirus/ antimalware system actively checks for malware files. Other common browser hijacks will pop up a message saying you need to download an emergency update to Firefox or click to install free anti-virus software. Ensure that these kinds of applications update silently in the background so you won’t be fooled.

What to do if you think a ransomware attack is underway

If you suspect you’ve just landed on a site that’s infected with ransomware, disconnect your machine from the outside world. Unplug your Ethernet connection. Turn off your WiFi. If you move fast enough, you may protect network-attached drives from being affected. Get off the network and fire your anti-virus and anti-malware engines up immediately.

First – as I already stated – it’s a mistake to pay. (If you do decide to pay, it should always be a last resort.) Your first step should be to verify that it’s REALLY ransomware or malware, and not a browser hijack or a scareware popup that goes away when you close your browser and restart your computer.

It’s really ransomware: where to go for help (or to help others)

Ransomware can be divided roughly into two groups: sophisticated proware, and amateur hour. Even if it’s not just a scareware popup, some ransomware can be circumvented with built-in system tools. I know someone who was recently hit with Spora, a nasty and sophisticated cryptoware for which there’s no current fix. However, she managed to retrieve some of her files using Windows Previous Versions and volume shadow copies (VSS).

DON’T start with a random Google search. A huge number of search results from “how to fix ransomware XYZ” will be spurious or links infected with malware. (Criminals work the SEO to try to direct you back into their web.) Using another computer if you have to, go directly to the blog or forum maintained by your anti-virus or anti-malware solution provider and search for information there. In fact, major antivirus providers offer free ransomware discovery or decryption tools on their websites, and non-profit sites exist that will help you identify what’s infecting your system, so any of these links are also a good place to start:

Subscribing to security newsfeeds is a good way to keep your background knowledge high. If you want to read up on ransomware before you’re hit with an attack, Digital Guardian released its list of The Top 50 InfoSec Blogs You Should Be Reading (including authorities like Krebs On Security).

If you or someone you know is a victim of ransomware, it will tell you there’s a deadline of 48 to 96 hours to pay the ransom to get a private key. After the time has expired, the private key is gone and your data is forever encrypted. It’s possible to set the BIOS clock back in an attempt to delay the process and explore options. However, once the data is encrypted, you may not be able to access the files. If you can, make a new backup image of your files, even if they’re encrypted – you can always try decryption now, or at a later date once new solutions are released. (This is exactly what I told my friend who was a Spora victim to do with the rest of her hard drive that’s still encrypted.)

While this can’t be a comprehensive guide to fixing ransomware, I hope it was able to point you in the right direction. Before I leave, I want to share this amazing timeline of the varieties of ransomware released between May 2016 and today.

Until next time,

George Monsalvatge

 

Ransomware! What is it, and what can I do about it? (Part 1 of 2)

April 4, 2017 at 3:08 pm | Posted in cybersecurity, Knowledge, Technical Tips | 1 Comment
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Ransomware! What can I do about it?

We live in dangerous times. Your cranky grandfather was right: they are out to get you – but who are “they,” and what the heck are we talking about? Ransomware, of course. It’s out there, and its coming for you.

Mobsters extort money from people. You may be a fan of mobster movies or the Sopranos on HBO, but it’s only fun to watch mobsters at work when you’re not the one getting the shakedown. I don’t know Tony Soprano, and besides, I like Joe Pesci’s character in Lethal Weapon III better than his characters in Casino or Goodfellas. Extortion could be coming to a PC, Mac, or even Linux box near you in the form of ransomware.

Mobsters

It’s fun to watch these guys on TV. It’s not so fun to be a victim in your own home.

First I’ll go over the basics of how ransomware works.  I’ll explain the most common mistake you may be making – even if you’re an IT professional – that might leave you a victim of a drive-by drive-locking. And, of course, I’ll tell you the best ways to prepare to fight ransomware.

In my follow-up post I’ll go over some specific strategies to harden your e-mail and firewall against malware attacks and share a recommended reading list for infosec news.

How the shake-down starts

You can be extorted on the Internet without being infected with ransomware. Hijacking someone’s social media account (like Instagram), changing their login, and then demanding payment for the user credentials is extortion, but it isn’t ransomware.

Ransomware is a type of malware that infects your computer and encrypts your files or blocks access to your own data. The ransomware displays a message stating that the attacker will unlock your files for a price, and that payment should be rendered through a nominally untraceable electronic currency, such as BitCoin or MoneyPak. It usually gives you a time limit and threatens to permanently destroy your data if you don’t pay before the deadline.

For home users, that price is usually set between $150-300 USD or Euros. For business victims, the demand might start at $500 – or it could be $10,000 and escalate from there.

How did the ransomware get there?

The malware that carries the encrypting payload is loaded on your computer in a number of ways. The malware could have come from a downloaded file or from a browser hijack. The malware could be hidden in another program. Any web site that hosts third-party ads, like recipe blogs and your favorite vintage car forum, can be a huge vector for malware no matter how innocent the site itself is; just visiting the site or clicking an ad by accident can expose you to a silent malware download.

No operating system is immune (not even mobile phones or home appliances). Ransomware can affect PCs running any operating system and Macs. Yes, I said Macs. A ransomware called KeRanger was found in a BitTorrent software that was designed to install on the Apple OS X operating system. The KeRanger malware will encrypt files on your computer and try to encrypt Time Machine backup files to prevent you from recovering the data from a backup. The KeRanger malware attackers want $400 for the private key.

[Note: If you frequent Bittorrent sites, you know they have pirated files for download from shady servers. Don’t be surprised when you lie down with dogs and get up with fleas.]

What happens when the ransomware activates?

A majority of active ransomware uses a variation of Cryptolocker. Once the malware is loaded on your computer, it first contacts a central server on the Internet. That server creates a unique encryption key pair. A public key that is kept on the local computer and the private key used for decryption that is kept on the attacker’s central server. Once the public key and private key are created, the malware will begin encrypting files locally on your computer and any mapped drives.

The attacker has the private key and will sell it you to use to decrypt your files. If you have ransomware on your computer, you will get a pop-up that instructs you to pay money via BitCoin, MoneyPack, or something similar.

CryptoLocker

When ransomware is an offer you can’t refuse

Ransomware is common because it’s cheap to implement (for the attackers) and hugely effective. Steve Perry of Journey once sang the wheel in the sky keeps on rolling. Well, when it stops rolling, everybody raises hell. If your business has an outage, the data has to be restored. Money never sleeps; your network has to hum along 24 hours day. The Internet is like Waffle House: it never closes. (I can go on and on in this vein. Don’t try me.) In short, your customer expects that you will never be closed and that your (and their) data will always be there. Ransomware that locks your data up has kneecapped you right in the business income.

Many business victims would rather just pay the ransom and get access restored. The logic goes that it’s better to pay rather than to lose an unknown amount of revenue from the downtime they’ll incur while trying to root out the infection and restore systems.

Unfortunately, this is EXACTLY why ransomware continues to flourish, and exactly the wrong response to an attack.

Whatever you do, if at all possible: DON’T. PAY. THE. RANSOM. There are two very important reasons why this is a bad idea:

  1. You are dealing with criminals. There is no guarantee you’ll even get the private key to unlock your files.
  2. If you pay, you only encourage this crime to continue.

However, it’s easy for me to lecture you on this. I didn’t have my laptop full of all my kids’ photos, my graduate thesis, the last video of my late wife, or some other valuable data extorted from me. I can honestly say that if I was in that situation, I don’t know whether I would pay to get that data back.

The #1 mistake that leaves you vulnerable to ransomware

Pirating movies. Frequenting shady websites. Buying a “smart” refrigerator and letting it connect to your home wireless router without changing the default settings. Failing to keep your anti-virus programs updated. All of these are bad ideas, but they’re not the #1 mistake that makes you most likely to shell out the (bit)coin and retrieve your data.

Sure, our goal should be to never get infected with ransomware. But given the speed at which these attacks evolve, it’s not realistic to assume that our firewalls and anti-virus software will be 100% effective. The best offense is always a good defense; with ransomware, the best defense is a secure recent backup.

Threats only work if you’re afraid of the consequences. With a secure external backup, you can wipe your system and walk away from the demands.

After all, if you have a full image of your system and a secure external copy of your data, you can risk losing a few days’ worth of files while you wipe and reimage your system to remove the malware.  You could use a snapshot to restore your system, or clean your machine and restore your data.

Unfortunately, home users (and many small businesses) rely on cloud-connected file servers like OneDrive and Dropbox to back up the physical copies stored on our hard drive. Or we never keep a local copy of our files, assuming that our cloud providers have better intrusion security than we could provide for ourselves.

Rest assured: backing up to the cloud won’t protect your data. Malware like Cryptolocker can encrypt files on mapped drives and external drives. This definitely means your Dropbox, OneDrive, Google Drive or cloud service that is mapped to your machine can also be infected and your cloud-based files can be encrypted just like your local ones.

You should treat the personal data on your laptop or desktop, company data on your company’s laptop, or data on your company’s devices just like the data on corporate servers and schedule regular backups. Furthermore, you need to back up to external drives.

You should have your drives backed up to an external drive on a regular basis or use a backup service that does not use an assigned drive. Why does it have to be an external drive? Variations of Cryptolocker can check for shadow files on your computer and disable or delete them.

How often you perform backups will determine how much you lose.

In our next post…

In my next post I’ll share a few ways to harden your OS, firewall, email, and end users – even your grandma – against some common ransomware entry points. I’ll also suggest ways to handle the dreaded “friends and family support call.”

Until next time,

George Monsalvatge

 

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