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Posts Tagged ‘ransomware’
February 10th, 2015

Mobile Crypto-Ransomware Simplocker now on Steroids

In June 2014, we told you about mobile ransomware called Simplocker that actually encrypted files (before Simplocker, mobile ransomware only claimed to encrypt files to scare users into paying). Simplocker infected more than 20,000 unique users, locking Android devices and encrypting files located in the external storage. Then, it asked victims to pay a ransom in order to “free” the hijacked device. It was easy to decrypt the files affected by this variant of Simplocker, because the decryption key was hardcoded inside the malware and was not unique for each affected device.

Dangerous unique keys

keyBut now there is a new, more sophisticated variant of Simplocker in town that has already infected more than 5,000 unique users within days of being discovered. The reason why this variant is more dangerous than its predecessor is that it generates unique keys for each infected device, making it harder to decrypt infected devices.

To use an analogy, the original variant of Simplocker used a “master key” to lock devices, which made it possible for us to provide a “copy of the master key” (in the form of an app, Avast Ransomware Removal) to unlock already infected devices. The new variant however, locks each device with a “different key” which makes it impossible to provide a solution that can unlock each infected device, because that would require us to “make copies” of all the different “keys”.

Why would anybody install Simplocker?!

The reason why people install this new variant of Simplocker is because it goes undercover, meaning people don’t even realize that what they are installing is ransomware!

Fake Flash

Tricky Simplocker pretends to be a real app.

 

In this case, the new variant of Simplocker uses the alias “Flash Player” and hides in malicious ads that are hosted on shady sites. These ads mostly “alert” users that they need Flash Player installed in order to watch videos. When the ad is clicked on, the malicious app gets downloaded, notifying the user to install the alleged Flash Player app. Android, by default, blocks apps from unofficial markets from being installed, which is why users are notified that the install is being blocked for security reasons.
Device Admin Request

 

Users should listen to Android’s advice. However, users can go into their settings to deactivate the block and download apps from unknown sources. Once installed, a “Flash Player” app icon appears on the device and when it is opened the “Flash Player” requests the user grant it administrator rights, which is when the trouble really begins.

As soon as the app is granted administrator rights, the malware uses social engineering to deceive the user into paying ransom to unlock the device and decrypt the files it encrypted. The app claims to be the FBI, warning the user that they have found suspicious files, violating copyright laws demanding the user pay a $200 fine to decrypt their files.

device-2015-02-05-143216  FBI warning is an example of social engineering

What should I do if I have been infected?

We do NOT recommend you pay the ransom. Giving into these tactics makes malware authors believe they are succeeding and encourages them to continue.

If you have been infected by this new strain of Simplocker, back up the encrypted files by connecting your smartphone to your computer. This will not harm your computer, but you may have to wait until a solution to decrypt these files has been found. Then boot your phone into safe mode, go into the administrator settings and remove the malicious app and uninstall the app from the application manager.

Avast protects users against Simplocker

Avast Mobile Security protects users against both the old and new variant of Simplocker, the new variant is detected as: Android:Simplocker-AA.

A more technical look under the hood:

As the fake FBI warning is being shown to users, the malware continues working in the background, doing the following: Read more…

January 19th, 2015

An old threat is back: Ramsonware CryptoWall 3.0. Get Avast for protection.

The nightmare is back! Your security could be seriously compromised if you do not act now. Install and update your Avast for PC before is too late. The original version of CryptoWall was discovered in November 2013, but a new and improved variant of the CryptoWall ransomware starts to infect computers all over the world last days. It’s the CryptoWall 3.0. Some sources estimate that it has already infected over 700,000 computers up to version 2.0.

Avast detects and blocks ransomware

Avast Software Updater can help identify software that needs to be updated.

CryptoWall is a malware that encrypts certain files in your computer (and secure delete the original ones) and, once activated, demands a fine around $500 as a ransom to provide the decryption key. You’re asked to pay in digital Bitcoins in about 170 hours (almost a full week). After that period, the fee is raised to $1000.

You could be asking why haven’t the authorities blocked the financial funding of them? They use unique wallet ID for each victim into their own TOR anonymity servers. For the user to be able to pay the ransom, he needs to use a TOR-like connection called Web-to-TOR. Each TOR gateway redirects the victim to the same web page with the payment instructions. The commands and communication control is now done using Invisible Internet Project (I2P) instead of Tor.

Infection could reach you in various ways. The most common is as a phishing attack, but it also comes in email attachments and PDF files. The malware kit also abuses various vulnerabilities in unpatched – read non up-to-date – Flash, Java, browsers and other applications to drop the CryptoWall ransomware.

How Avast prevents the infection

1. Avast Antispam and antiphishing protection prevents some vectors distribution.

2. Virus signature block all known ransomwares versions. Remember that Avast automatic streaming updates releases hundreds of daily updates for virus definitions.

3. Community IQ intelligence and sensors of our more than 220 million users that detects malware behavior all over the world. See how it works in this YouTube video.

4. Keeping your software updated is another security measure that prevents the exploit of their vulnerabilities. Learn how Avast Software Updater can help you with this job.

What more can I do?

Avast also helps in prevention of this disaster through its Avast Backup that allows you to keep all your important files in a secure and encrypted way. We also recommend local backup, as the new malware could also attack other drives and even cloud storage. Did you know that Avast Backup also performs local copies of the files? You can enable it at Settings > Options > Local backup, and configure the backup location (better an external drive) and also versioning of the files. Remember to disconnect the external drive from the computer (and the network) to prevent infection of the backups by CryptoWall and further encryption of the files.

Avast Software’s security applications for PC, Mac, and Android are trusted by more than 200-million people and businesses. Please follow us on Facebook, Twitter and Google+.

August 27th, 2014

Self-propagating ransomware written in Windows batch hits Russian-speaking countries

Ransomware steals email addresses and passwords; spreads to contacts.

Recently a lot of users in Russian-speaking countries received emails similar to the message below. It says that some changes in an “agreement’ were made and the victim needs to check them before signing the document.

msg
The message has a zip file in an attachment, which contains a downloader in Javascript. The attachment contains a simple downloader which downloads several files to %TEMP% and executes one of them.
payload
The files have .btc attachment, but they are regular executable files.

coherence.btc is GetMail v1.33
spoolsv.btc is Blat v3.2.1
lsass.btc is Email Extractor v1.21
null.btc is gpg executable
day.btc is iconv.dll, library necessary for running gpg executable
tobi.btc is   Browser Password Dump v2.5
sad.btc is sdelete from Sysinternals
paybtc.bat is a long Windows batch file which starts the malicious process itself and its replication

After downloading all the available tools, it opens a document with the supposed document to review and sign. However, the document contains nonsense characters and a message in English which says, “THIS DOCUMENT WAS CREATED IN NEWER VERSION OF MICROSOFT WORD”.

msg2 Read more…

August 19th, 2014

Reveton ransomware has dangerously evolved

The old ransomware business model is no longer enough for malware authors. New additions have made Reveton into something even more powerful.

Reveton

The latest generation of Reveton, the infamous “police” lock screen/ransomware, targets new black market business. The authors upped the ante of the despised malware from a LockScreen-only version to a dangerously powerful password and credentials stealer by adding the last version of Pony Stealer.  This addition affects more than 110 applications and turns your computer to a botnet client.

Reveton also steals passwords from 5 crypto currency wallets. The banking module targets 17 German banks and depends on geolocation. In all cases, Reveton contains a link to download an additional password stealer. The most common infection is via the well-known exploit kits, FiestaEK, NuclearEK, SweetOrangeEK, etc.

Pony stealer module

Reveton use one of the best password/credentials stealer on the malware scene today. Pony authors conduct deep reverse engineering work which results in almost every password decrypted to plain text form. The malware can crack or decrypt quite complex passwords stored in various forms.

The stealer includes 17 main modules like OS credentials, FTP clients, browsers, email clients, instant messaging clients, online poker clients, etc and over 140 submodules.
Reveton modules

Read more…

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June 19th, 2014

How to use avast! Ransomware Removal?

howto2_en avast! Ransomware Removal removes SimpLocker, Cryptolocker, or any other type of ransomware from infected devices.

A few days ago, we announced a new app that kills Android ransomware. After being available on Google Play, the app has already been received with enthusiasm. We spotted some questions regarding the tool on social media and addressed them to our support team. In this article we will explain how to install, how to run the tool, and why it is important to uninstall it after AVAST has done its job! First, our COO explains what SimpLocker, on of Android’s dreaded ransomware, can do to your phone.

SimpLocker blocks access to files on infected mobile devices by encrypting them. Without our free ransomware removal tool, infected users have to pay $21 to regain access to their personal files. SimpLocker  is the first ransomware that actually encrypts files, so we developed a free tool for people to restore them. – said Ondrej Vlcek, Chief Operating Officer at AVAST Software.

1. How can I install the avast! Ransomware Removal tool if my mobile is already being blocked by the malware?

blog_arrThis is a very good question, and we know how to get around this. All users can install the app remotely, but must access Google Play from your computer, not your mobile device. Follow these simple steps:

  • Log in to Google Play with the same user information you use to log in to your phone
  • Find the avast! Ransomware Removal app
  • Click the “Install” button and the app will be installed on your device shortly

2. How do I can run the application?

  • After the app is installed on your phone, click the app name from within the notification bar
  • The app will run and provide you with further instructions
  • Run a scan and wait until it has successfully removed the ransomware
  • Uninstall the app at the end (you can install it again in the future if necessary).

3. Why am I prompted to uninstall avast! Ransomware Removal once I finish the scan and the ransomware has been removed?

This is one of the most frequent questions being asked by users, so we asked for more details from our experts. Here is an explanation from AVAST developer Jan Svehlak:

Ransomware locks users out of their devices, meaning the malware loads its ransom screen before other apps even have a chance to load. The avast! Ransomware Removal app needs to override the SimplLocker malware first, in order to access the device. However, if not uninstalled after the scan, it will continue to override all apps on the device, meaning it will block all other apps from opening. Therefore avast! Ransomware Removal needs to be uninstalled after accomplishing its task; unlocking your device.

Last, but not least, we believe that prevention is much more efficient than fixing an existing issue. To keep your devices protected from Cryptolocker, SimpLocker, and other ransomware, make sure to also install avast! Free Mobile Security & Antivirus from the Google Play store. It can detect and remove the malware before it is deployed.

Thank you for using avast! Antivirus and recommending us to your friends and family. For all the latest news, fun and contest information, please follow us on FacebookTwitter and Google+. Business owners – check out our business products.

 

June 17th, 2014

AVAST kills Android ransomware with new app

avast! Ransomware Removal app eliminates Android ransomware and unlocks encrypted files, for free!

ransomware-removal-suitcase

Ransomware, the terror of Windows that locks computers, encrypts the files, then demands a hefty payment to unlock them, has made its way to Android smartphones.

“The ransomware problem is growing like hell – and it’s no longer just threatening users – the new versions actually do encrypt your files,” said Ondrej Vlcek, Chief Operating Officer at AVAST Software.

AVAST Software just released a new app called avast! Ransomware Removal that will eliminate the malware from an infected device. Get it free for your Android smartphone and tablet from the Google Play Store.

avast! Ransomware Removal will tell you if your phone has ransomware on it. If you are infected, it will eliminate the malware. Android users who are clean, can use the free app to prevent an infection from happening.

This short video shows you what actually happens when ransomware infects your Android smartphone.

The next wave of attacks

Savvy malware writers know where the next round of victims can be found. With Android at a whopping 80% worldwide market share, as well as “billions” of remaining mobile subscribers ready to upgrade to smartphones, the targets are numerous.

After detecting the massive growth of ransomware on PCs, this spring AVAST Virus Lab researchers saw the malware migrating to the Android platform. Analysts identified fake government mobile malware, and early this month a new ransomware called SimplLocker proved to be successful. This proof-of-concept worked so well encrypting photos, videos, and documents stored on smartphones and tablets, that the Virus Lab immediately ordered a tool from our mobile development team to combat it - avast! Ransomware Removal.

SimplLocker blocks access to files contained on mobile devices. Without our free ransomware-removal tool, infected users have to pay $21 to regain access to their personal files,” said Vlcek. “SimplLocker is the first ransomware that actually encrypts these files, so we developed a free tool for people to restore them.”

Find. Kill. Prevent.

Install avast! Ransomware Removal to find out if your Android devices are infected and to get rid of an infection. Anyone infected by SimplLocker, Cryptolocker, or any other type of ransomware can download the free avast! Ransomware Removal tool, and then install the app remotely on the infected device. Once installed, you can easily launch the app to scan the device, remove the virus, and then decrypt your hijacked files.

To keep your devices protected from Cryptolocker, SimplLocker, and other ransomware, make sure to also install avast! Free Mobile Security & Antivirus from the Google Play store. It can detect and remove the malware before it is deployed.

Thank you for using avast! Antivirus and recommending us to your friends and family. For all the latest news, fun and contest information, please follow us on FacebookTwitter and Google+. Business owners – check out our business products.

 

June 5th, 2014

SimpLocker does what its name suggests: Simply locks your phone!

A new Android mobile Trojan called SimpLocker has emerged from a rather shady Russian forum, encrypting files for ransom. AVAST detects the Trojan as Android:Simplocker, avast! Mobile Security and avast! Mobile Premium users can breathe a sigh of relief; we protect from it!

malware, mobile malware, Trojan, SimplockerThe Trojan was discovered on an underground Russian forum by security researchers at ESET. The Trojan is disguised as an app suitable for adults only. Once downloaded, the Trojan scans the device’s SD card for images, documents and videos, encrypting them using Advanced Encryption Standard (AES). The Trojan then displays a message in Russian, warning the victim that their phone has been locked, and accusing the victim of having viewed and downloaded child pornography. The Trojan demands a $21 ransom be paid in Ukrainian currency within 24 hours, claiming it will delete all the files it has encrypted if it does not receive the ransom. Nikolaos Chrysaidos, Android Malware Analyst at AVAST, found that the malware will not delete any of the encrypted files, because it doesn’t have the functionality to do so. Targets cannot escape the message unless they deposit the ransom at a payment kiosk using MoneXy. If the ransom is paid the malware waits for a command from its command and control server (C&C) to decrypt the files.

What can we learn from this?

Although this Trojan only targets a specific region and is not available on the Google Play Store, it should not be taken lightly. This is just the beginning of mobile malware, and is thought to be a proof-of-concept. Mobile ransomware especially is predicted to become more and more popular. Once malware writers have more practice, see that they can get easy money from methods like this, they will become very greedy and sneaky.

We can only speculate about methods they will come up with to eventually get their malicious apps onto official markets, such as Google Play, or even take more advantage of alternative outlets such as mobile browsers and email attachments. It is therefore imperative that people download antivirus protection for their smartphones and tablets. Mobile devices contain massive amounts of valuable data and are therefore a major target. 

Ransomware can be an effective method for criminals to exploit vulnerable mobile users, many of which don’t back up their data. Just as in ransomware targeting PCs, this makes the threat of losing sentimental data, such as photos of family and friends or official documents, immense.

Don’t give cybercriminals a chance. Protect yourself by downloading avast! Mobile Security for FREE.

June 4th, 2014

How to protect yourself from the coming virus apocalypse

After the takedown of a major botnet, users have a “two-week window” to protect themselves against a powerful computer attack that ransoms people’s data and steals millions of dollars from unsuspecting victims. 

Zeus_Banner_blhd01
If you read our blog, you are familiar with the dangers of the Zeus Trojan and ransomware, and how people get infected. Here’s a quick review:

1. The victim opens a carefully crafted email which is designed to look like it came from their bank or a well-known company.
2. The victim clicks on and runs an email attachment.
3. Malicious software like the one making the news now, Gameover Zeus, releases a Trojan which searches the computer for passwords and financial data.
4. Once Gameover Zeus finds what it’s seeking, cybercrooks instruct CryptoLocker, ransomware software, to hijack the computer, encrypt the files, and demand payment for it to be unlocked. To get access to your computer again, you must pay a ransom within a set amount of time.
5. Once infected, the computer becomes part of the global botnet.

The good news

Led by the FBI, agents from Europol and the UK’s National Crime Agency (NCA) brought two computer networks that used the Gameover Zeus botnet and Cryptolocker ransomware to infect up to a million computers and cost people more than $100 million under control of the good guys.

The bad news

As we explained in our blog post yesterday, GameOver Zeus May not be as Over as You Think, cybercrooks could conceivably build another botnet to replace the ones that were shut down.

Why the two-week window?

This window is based on the amount of time the FBI thinks they can ”hold the upper-ground against the cybercriminals.” Two weeks should be enough time for computer users to update their operating system software and security software and disconnect infected computers.

Steps to take now to protect your computer

Read more…

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June 3rd, 2014

GameOver Zeus May not be as Over as You Think

The FBI, along with the Department of Justice, announced a multinational effort on their website that has disrupted a botnet called GameOver Zeus. GameOver Zeus has infected millions of Internet users around the world and has stolen millions of dollars.

AVAST detects and protects its users from CryptoLocker and GOZeus.

Everyone should have up-to-date antivirus protection on their computer. AVAST detects and protects its users from CryptoLocker and GOZeus.

 

The UK’s National Crime Agency (NCA) has worked closely with the FBI to crack down on the GameOver Zeus botnet. The NCA has given infected users a two week window to get rid of the malware and those lucky enough to have thus far been spared, the opportunity to safeguard themselves against future attacks. The two week window is an estimation on how long it will take cybercriminals to build a new botnet. The FBI has stated on their website that GameOver’s botnet is different from earlier Zeus variants in that the command and control infrastructure communicates peer-to-peer, rather than from centralized servers. This means that any infected computer can communicate controls to other infected devices. If cybercriminals build a new botnet, which will likely happen, the new botnet can resurrect dormant infected machines and continue to infect new users while stealing financial and personal information from innocent victims.

Do you really have two weeks, and what should you do?

Who knows how long it may take for a new botnet to emerge; it could appear tomorrow or in two weeks. People should not take this threat lightly and should act immediately. Read more…

May 7th, 2014

Fake government ransomware holding Android devices hostage

Ransomware, which has already made its rounds on Windows, is now increasingly targeting the Android operating system. A new piece of mobile malware claiming to be the government under the name Android: Koler-A is now targeting users.

We have full control of your phone – give us $300 and we’ll give it back

Obrázek 1-1

The ransomware is pushed automatically from fake porn sites visited by Android users via a malicious .apk file that appears in the form of an app. The innocent appearance of the app deceives users and is a powerful social engineering tactic used by malware developers to trick people into installing malicious apps. The form of delivery is not the only thing that makes the app suspicious and potentially dangerous, but the access it seeks are highly unusual and alarming. The ransomware requests full network access, permission to run at startup and permission to prevent the phone from sleeping. Once installed the granted access allows the ransomware to take control of the device. The full network access allows the malicious app to communicate over the web and download the ransom message that is shown on the captive device. The permission to run at startup and prevent the phone from sleeping fully lockdown the phone, preventing victims from escaping the ransom message.

The ransomware localizes fake government messages, depending on the users GPS location, accusing them of having viewed and downloaded inappropriate and illegal content. What does the ransomware do next? Demands ransom of course! The ransom to regain access to the device including all of its apps, which it claims are all encrypted, is set at around $300 and is to be paid through untraceable forms of payment such as MoneyPak.

avast! Mobile Security safeguards against ransomware

Both AVAST’s free and premium mobile security apps, avast! Mobile Security and avast! Mobile Premium, protect customers from falling for the devious apps containing ransomware. AVAST detects this ransomware under the name Android: Koler-A and blocks its execution.

We recommend that everyone be cautious when downloading apps, especially from unofficial app markets. We also urge users to not open any files that have been downloaded to their device without their consent. Always check what apps want to access and in addition to being cautious, we advise people download antivirus to protect their devices. This new ransomware appearing on Android is the perfect example of how malware is starting to move away from the PC environment and into our pockets and there are no signs of this slowing down.

Thank you for using avast! Antivirus and recommending us to your friends and family. For all the latest news and product information, please follow us on Facebook, Twitter, Google+ and Instagram. Business owners – check out our business products.

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