Feb 16 2018

Free Ransomware Available on Dark Web

The McAfee Advanced Threat Research team recently analyzed a ransomware-as-a-service threat that is available for free and without registration. This malware was first seen in July 2017 with the extension .shifr. It has now appeared in recent detections with the extension .cypher.

Ransomware-as-a-Service

Ransomware-as-a-service is a cybercrime economic model that allows malware developers to earn money for their creations without the need to distribute their threats. Nontechnical criminals buy their wares and launch the infections, while paying the developers a percentage of their take. The developers run relatively few risks, and their customers do most of the work.

Some ransomware-as-a-service, such as RaaSberry, use subscriptions while others require registration to gain access to the ransomware. The ransomware developer hosts a service on the “dark web” that allows any buyer to create and modify the malware. For example, the buyer can add custom ransom notes and the amount of the payment. More advanced services offer features such as evasion techniques to avoid detection and analysis. The service can also offer a control server with an administration panel to manage each victim. This system is convenient for both the developer, who makes money by selling malware, and for buyers, who gain ready-to-deploy ransomware without needing any specific coding knowledge.

The underground economy behind this service is well organized, effectively offering a cybercrime infrastructure. Basically, the ransomware is available on a website. The buyer sets up the ransomware by adding a wallet address. The ransomware is then available to download. The buyer just needs to customize and spread the malware. When a victim pays the ransom, a percentage is delivered both to the buyer and to the malware coder.

 

The ransomware is available on the TOR network at hxxp://kdvm5fd6tn6jsbwh.onion. A web page guides buyers through the configuration process.

On the configuration page, a generic XMPP address suggests we may have found a demo version of the ransomware.

On the page, the buyer need only to add a Bitcoin wallet address and the amount of the ransom. Once that is done, the malware is generated and can be downloaded. With this malware, the developer earns a 10% commission on every payment. Now let’s look at the malware sample.

Dynamic Analysis 

When the malware launches on the victim’s system, it checks for an Internet connection. If there is none, it exits the process. Otherwise, it contacts the following addresses to download the encryption key:

Once the file is running, it creates several files on the system:

  • Encryption_key: the RSA key encrypted in AES
  • Lock_file: an indicator that the system is encrypted
  • Uuid_file: a reference for the infected machine. A TOR address is generated with this ID.

The encryption key is downloaded from hxxps://kdvm5fd6tn6jsbwh.onion.to/new_c/xmKksHw53W433lmvNsdzGxqWLcPLA44Dyna.

The ransom note is created on the desktop.

The file “HOW_TO_DECRYPT_FILES.html” gives a link to the TOR network.

Once the files are encrypted, the ransom note is displayed in HTML and points to the TOR site hxxp://kdvm5fd6tn6jsbwh.onion/ with the ID of the infected machine.

Allegedly after payment, the victim can download the file decrypter.exe and unlock encrypted files, which have the extension .cypher.

The malware encrypts the following file extensions:

The targeted extensions include many picture and photography files related to Canon, Kodak, Sony, and others. There are also extensions for AutoCAD, Autodesk projects, scalable vector images, and Microsoft Office files. These files are mostly used by designers, photographers, architect—and many others.

Digging Deeper

The malware runs on 64-bit systems and is coded in Golang (“Go language,” from Google), a programming language similar to C with some improvements in error management. It is not common to find malware using Golang, although this is not the first time that we have analyzed such malware. This threat is pretty big compared with most other malware, larger than 5.5MB. The file size can make analysis more difficult and can also help evade hardcoded antimalware file-inspection sizes.

Reverse engineering in Golang is a bit different than other languages. Golang binaries are usually bigger than other executables. (By default, the compiler statically links the program’s libraries, resulting a bigger file.)

A drawback for attackers is that such big binaries can be easily detected on a corporate network. Large files are “noisier” and may appear suspicious when arriving from an external source. They can also be less convenient for attackers to deal with because they can make the infection process more difficult.

The first interesting function to analyze in a Golang binary is the “main_main.” The malware starts by gathering environment variables. It then checks whether the file “lock_file” exists in the directory C:\Users\<username>\AppData\Roaming.

The function “main_Exists” will check for the file. If it does not exist, the malware exits the process.

If the file does exist, the malware downloads the public key from the control server.

The malware contacts the address  hxxps://kdvm5fd6tn6jsbwh.onion/new_c/<nameofmalware>. The encryption public key is stored directly on the website.

This address is generated when the buyer creates the ransomware on the developer’s web page; thus the same malware encrypts files with the same public key.

The malware generates the AES key and tries to find any network share by querying the letters.

This function tries to find network shares:

Before a file is encrypted, the malware creates another file in C:\Users\<username>\AppData\Roaming\uuid_file to use as a victim identifier.

The malware encrypts the files using AES and deletes them after encryption with the function “os.remove” to avoid any simple forensic recovery.

The decrypter, which can be downloaded, works in a similar way but it requests the private key that the victims must pay for at hxxps://kdvm5fd6tn6jsbwh.onion.to/get_privkey/math/big. The mechanism behind the encryption routine seems to be on the online server and the decryption key cannot be easily recovered.

The following information describes the decrypter.

Conclusion

Cybercrime-as-a-service is not new, yet it is now more widespread than ever. In this case, the malware is available for free but the ransomware developer earns a 10% fee from each victim who pays a ransom. The use of Golang is not common for malware. Most ransomware-as-a-service is not free, which could indicate this might be a demonstration version, or a proof of concept for future sale.

This malware is not advanced and was coded without evasion techniques, such as DGA, SSL for control, encryption, or even file compression. Looking at the targeted file extensions suggests the victims can range from general home or business users to the graphics industry. Although such malware is not difficult to analyze, it can be very destructive in a corporate environment.

Keep in mind that paying a ransom is no guarantee of receiving a decryption key. McAfee advises that you never pay a ransom. You can find further information and help on unlocking some ransomware threats at https://www.nomoreransom.org.

McAfee detects this threat as Ransomware-FPDS!0F8CCEE515B8.

 

Indicators of Compromise

Hashes:

  • cb73927aa749f88134ab7874b15df898c014a35d519469f59b1c85d32fa69357
  • 0622fcb172773d8939b451c43902095b0f91877ae05e562c60d0ca0c237a2e9c

IP address:

  • hxxp://kdvm5fd6tn6jsbwh.onion

Files created:

  • C:\Users\<username>\AppData\Roaming\uuid_file
  • C:\Users\<username>\AppData\Roaming\lock_file
  • C:\Users\<username>\AppData\Roaming\encryption_key
  • C:\Users\< username >\Desktop\HOW_TO_DECRYPT_FILES.html

Encryption extension:

  • .cypher

References:

https://www.virustotal.com/en/file/0622fcb172773d8939b451c43902095b0f91877ae05e562c60d0ca0c237a2e9c/analysis/

https://isc.sans.edu/forums/diary/Ransomware+as+a+Service/23277/

 

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Dec 18 2017

Operation Dragonfly Analysis Suggests Links to Earlier Attacks

On September 6, Symantec published details of the Dragonfly campaign, which targeted dozens of energy companies throughout 2017. This attack was effectively Dragonfly 2.0, an update to a campaign that began in 2014.

Moving beyond our 2014 analysis of Dragonfly, our current focus looks at the attack’s indicators to determine whether we can glean any further information regarding the source and possible motivations of those behind the campaign. The campaign targets energy companies around the world by leveraging spear-phishing emails that, once successful, allow the attackers to download Trojan software. The Trojans provide access to the victims’ systems and networks.

Going Beyond Energy

Although initial reports showed Dragonfly attacks targeting the energy sector, investigations by McAfee Labs and the Advanced Threat Research team uncovered related attacks targeting the pharmaceutical, financial, and accounting industries. Everything about this campaign points to a well-prepared assault that carefully considers each target, and conducts reconnaissance before taking any measures to exploit compromised targets.

We saw the group use several techniques to get a foothold in victims’ networks, including spear phishing, watering holes, and exploits of supply-chain technologies via previous campaigns. By compromising well-established software vulnerabilities and embedding within them “backdoor” malware, the victims think they are installing software from a trusted vendor, while unaware of the supply-side compromise.

Once the attackers have a foothold, they create or gain user accounts to operate stealthily. Using the remote-desktop protocol to hop among internal or external systems, they connect either to a control server if the risk is minimal or use an internal compromised server to conduct operations.

The last wave of attacks used several backdoors and utilities. In analyzing the samples, we compared these with McAfee’s threat intelligence knowledge base of attack artifacts.

One of the starting points was a Trojan in the 2017 campaign with the following hashes:

  • MD5: da9d8c78efe0c6c8be70e6b857400fb1
  • SHA-256: fc54d8afd2ce5cb6cc53c46783bf91d0dd19de604308d536827320826bc36ed9

Comparing this code, we discovered another sample from the group that was used in a July 2013 attack:

  • MD5: 4bfdda1a5f21d56afdc2060b9ce5a170
  • SHA-256: 07bd08b07de611b2940e886f453872aa8d9b01f9d3c61d872d6cfe8cde3b50d4
  • Filename: fl.exe

The file was downloaded after a Java exploit executed on the victim’s machine, according to the 2013 attack report. After analyzing the 2013 sample, we noticed that some of the executable’s resources were in Russian.

Comparing the code, we find the 2017 sample has a large percentage of the same code as the backdoor used in the 2013 attacks. Further, some code in the 2017 backdoor is identical to code in the application TeamViewer, a legitimate remote administration tool used by many around the world. By incorporating the code and in-memory execution, the attackers avoid detection and leave no trace on disk.

The correlating hash we discovered that contained the same TeamViewer code was reported by Crysys, a Hungarian security company. In their report on about ‘“TeamSpy,” they mentioned the hash we correlated as well: 708ceccae2c27e32637fd29451aef4a5. This particular sample had the following compile date details: 2011:09:07 – 09:27:58+01:00

The TeamSpy attacks were originally aimed at political and human right activists living in the Commonwealth of Independent States (the former Soviet Union) and eastern European countries. Although the report attributes the attacks to a threat actor or actors and shared tactics and procedures, the motivations behind TeamSpy appear similar to those of the Dragonfly group. With identical code reuse, could the TeamSpy campaign be the work of Dragonfly?

But that’s not all of interest. We also discovered that the 2017 sample contained code blocks associated with another interesting malware family: BlackEnergy. Let’s look at an example of the code similarities we discovered:

A BlackEnergy sample from 2016 (at left) alongside a Dragonfly sample from 2017.

Self-deleting code is very common in malware, but it is usually implemented by creating a batch file and executing the batch instead of directly calling the delete command, as we see in the preceding examples.

The BlackEnergy sample used in our comparison was captured in the Ukraine on October 31, 2015, and was mentioned in our post on the evolution of the BlackEnergy Trojan. It is remarkable that this piece of code is almost identical in both samples, and suggests a correlation between the BlackEnergy and Dragonfly campaigns.

Actor Sophistication

Our analysis of this attack tells a story about the actors’ capability and skills. Their attack precision is very good; they know whom and what to attack, using a variety of efforts. Their focus is on Windows systems and they use well-known practices to gather information and credentials. From our research, we have seen the evolution of the code in their backdoors and the reuse of code in their campaigns.

How well do the actors cover their tracks? We conclude they are fairly sophisticated in hiding details of their attacks, and in some cases in leaving details behind to either mislead or make a statement. We rate threat actors by scoring them in different categories; we have  mentioned a few. The Dragonfly group is in the top echelon of targeting attackers; it is critical that those in the targeted sectors be aware of them.

The Dragonfly group is most likely after intellectual property or insights into the sector they target, with the ability to take offensive disruptive and destructive action, as was reported in the 2015 attack on the Ukrainian power grid by a BlackEnergy malware family.

 

We would like to thank the team at Intezer for their assistance and support during our research.

The post Operation Dragonfly Analysis Suggests Links to Earlier Attacks appeared first on McAfee Blogs.

Dec 18 2017

Looking Into the World of Ransomware Actors Reveals Some Surprises

During the preparations for our keynotes at McAfee’s recent MPOWER conference, we brainstormed a few topics we wanted to share with the audience. Ransomware was definitely on our agenda, but so much has already been said and written on the subject. What could we add that would be interesting?

We hit on the angle: to dive into this shady world and learn about the people behind these campaigns. There are several ways to approach this. We could go into forums and look for the individuals who discuss these campaigns or offer ransomware for sale. But that would be very time consuming and the chance of finding the right individuals would be small. There is a better way.

In most samples of ransomware, once they malware executes and files are encrypted, the “ransom note” appears. Either a background drop or a text file contains the details. During 2017 we saw many of these notes contain an email address for questions or for payment details and releasing files.

Example:

We looked at three months of unique ransomware samples and extracted either the images or the notes that contained the contact addresses. As new ransomware families popped up in our tracker, we verified them and added the addresses—because these fresh attacks made it likely the authors would interact with us.

But how could convince the actors to answer our questions? We took the role of students working on a master thesis and asked the actors if they would be willing to answer a few questions. For a couple of weeks we lived the role of students, eating lots of pizza, drinking sodas, and so on. (You have to live the role, right?)

We sent our emails and queried the actors who responded. One of our first observations was that of all the emails we retrieved, about 30 percent were either fake or nonexistent. So in these cases when files were encrypted and the victim decided to pay, using email to send evidence of payment was useless. The money was gone (as well as the files).

During the first week of our research we received answers back from some of the actors, but most were not willing to cooperate. That’s no surprise: They were cautious about revealing their identity.

During the second week, we had better luck and started to chat with a few. That number grew, and after a few weeks we had a great collection of conversations with the actors.

“Fast, easy, and safe”

When we asked why they started a career in ransomware, most answered with variations on “enough money” and “fast, easy, and safe,” especially when using anonymous email services and cryptocurrency for payments.

Homemade vs. Off the Shelf

Most of the actors we spoke with wrote their own ransomware. They had looked at the published source code but were clever enough to come up with their own variants that contained new techniques or different approaches to keep detections low. The longer they stayed out of sight of endpoint security solutions, the longer was their opportunity to make money.

Spending Their Ill-Gotten Gains

They spend the revenue they gained from their campaigns in various manners: travel, cars. One had many affiliates working for him so he was soon going to buy a house. One of the most surprising answers was that one turned to ransomware to “pay off his debts.”

Willing to Negotiate

Although they often have the image of being ruthless, almost all of them claimed a willingness to negotiate the ransom price in case victims could not afford to pay the demanded amount.

Tracking the Authors

One of the actors so enthusiastic he wanted to sell us ransomware code so we could pay off our college debts. Based on his answers and sharing of information, we noticed that he was not a very experienced actor and he gave clues on his whereabouts. In one of the conversations, he shared some examples, but the data was not scrubbed. By correlating the data he provided with other information, such as email time zones and mistakes in his English, we traced him to Dakar, Senegal. He not only sends ransomware but also sells botnets and other fraud-related services.

We found the research eye opening. Now we just need a few weeks in the gym to work off all the sodas and pizzas.

For those suffering from a ransomware attack, you have three options. The first two are bad: lose your files, or pay the ransom and hope (with no guarantee) for a key to unlock your files. The best option is to start with a visit to NoMoreRansom.org to see if a decryption tool is available.

Meanwhile, remember the standard advice on reducing your risk of picking up ransomware: Keep your OS, security, and application software up to date; exercise a healthy dose of skepticism even when you see messages that appear to come from legitimate sources; and do not click on links or open files from unknown names or organizations.

 

Learn more about the threat statistics we gathered in Q3, including ransomware in the McAfee Labs Threats Report, December 2017 and follow the team on Twitter at @McAfee_Labs.

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Dec 18 2017

McAfee Labs Reports All-Time Highs for Malware in Latest Count

In the third quarter of 2017, McAfee Labs reports all-time highs of new and total malware. What is causing the increasing numbers of malware that are submitted to us at an average rate of four new malware samples per second?

One major trend that continues in Q3 is the abuse of Microsoft Office–related exploits and the use of malicious code in macros that activates PowerShell to execute them, so-called fileless attacks.

In March, an exploit was released that took advantage of CVE-2017-0199, a vulnerability in how Microsoft Office and WordPad handle specially crafted files that could result in remote code execution. During Q3, we saw an increase in the number of crafted files that were submitted. We also noticed that many releases take advantage of a toolkit on GitHub that makes it quite easy to create a “backdoor” attack:

Another major event in Q3 was a massive spam campaign to distribute a new version of the infamous Locky ransomware “Lukitus.” Within 24 hours, more than 23 million emails were sent. Shortly after the first arrived, security company Comodo Labs discovered another campaign related to this attack that sent more than 62,000 spam emails distributing the ransomware.

With banking Trojans, we observed the greatest activity from the Trickbot Trojan. We saw several variations in which the actors added new features to their code, for example, cryptocurrency stealing, embedding the EternalBlue exploit, and employing different ways of delivering the malware, which primarily targets the financial sector.

Another banking Trojan family that appeared often during the quarter was Emotet. In several spamming campaigns users were asked to download a Microsoft Word document from several locations. From our analysis of the attached document, we found the payload was hidden in the macros that used PowerShell to install the Trojan.

These major campaigns and others caused a tsunami of spam email, distributing a tremendous number of samples that increased the malware storage demands of all of us in the security industry.

For more details and our usual statistics on malware, breach incidents, and web and network threats, read the McAfee Labs Threats Report, December 2017.

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