Sodinokibi

Sodinokibi, also called Revil, is dangerous ransomware-type malware. Among other tools, it uses advanced encryption techniques and can operate without connection to control servers. Sodinokibi is among the most complex Ransomware in the world.

Type
Ransomware
Origin
ex-USSR
First seen
1 April, 2019
Last seen
20 May, 2022
Also known as
REvil
Sodin
Global rank
25
Week rank
20
Month rank
20
IOCs
552

What is Sodinokibi ransomware?

Sodinokibi, sometimes also called REvil, is ransomware-type malware - it encrypts files on infected machines and demands a ransom from the victims to restore the files. Sodinokibi is distributed with a Ransomware-as-a-Service business model, allowing anybody who can pay can become an operator of the virus.

Sodinokibi is very sophisticated ransomware, seemingly developed by a group with vast experience in the field. It bears a lot of similarities to another malware called GandCrab - so much so, in fact, that it is believed to be created by the same group of cybercriminals. However, Sodinokibi can be considered a much-upgraded version than previous ones.

Sodinokibi ransomware is capable of encrypting files with curve25519/Salsa20 and encrypting keys with curve25519/AES-256-CTR. The malware uses 2 public keys to encrypt the private key of the user. In addition, this virus utilizes command and control server obfuscation and can operate using the asymmetric key scheduling algorithm, which allows the malware to function without connection to the C2.

General description of Sodinokibi

Sodinokibi first appeared on the radar of cybersecurity researchers in April of 2019, when the malware was featured in a campaign that exploited the Oracle WebLogic Server vulnerability.

The campaign began shortly before another similar malware called GandCrab was officially shut down for good. Some researchers believe that Sodinokibi is a “spiritual successor” of that malware, while others support the theory that it is, in fact, the next generation of the same virus. Some evidence suggests the theory to be correct.

Among such evidence are the vast similarities in the code of both malware and the fact that in the early stages of the Sodinokibi life cycle, criminals used to deploy GandCrab after running Sodinokibi on all infected machines as a precaution, likely because Sodinokibi wasn’t yet thoroughly tested in operation.

Another piece of evidence in favor of this theory is an attack that took place in February 2019, when GandCrab was used to infect victims by compromising Managed Service Providers. Sometime after, the same attack took place, and it featured Sodinokibi ransomware.

In addition, the fact that Sodinokibi malware became popular as its predecessor started to cease operations can not be ignored, and it would be strange to think about it as a coincidence. In addition to that, both malware use very similar distribution methods - something we will explore later in the article.

Finally, it is thought that GandCrab authors started “feeling the heat” and, while worried that their operation can be uncovered, decided to go under the radar by terminating sales in favor of a more advanced malware that could be sold to private parties.

Of course, neither of these points is solid evidence, and we can only imagine that both viruses result from the work of the same people.

Let’s talk about the behavior of Sodinokibi ransomware.

At the beginning of the execution process, the malware generates a mutex that has a hardcoded name. Then, it decrypts a configuration that is embedded. At this stage, Sodinokibi tries to get system privileges by exploiting CVE-2018-8453. In some cases, this step can be omitted in configuration or may not be successful. Then, it tries to obtain privileges by running as an admin.

Following the privilege escalation stage, the ransomware collects basic system and user data. If it finds that the UI or keyboard layout is set to one of the pre-programmed languages, the execution will be terminated. Many of these languages originate from post-USSR territories, suggesting that the malware authors also come from ex-USSR lands.

When the target PC lacks the specified UX or keyboard layout languages, the virus terminates processes by PRC value and proceeds to erase shadow copies. At this point, the data encryption process begins. The ransomware encrypts all user files unless some exceptions are found in the configuration. This is where an attacker can customize their campaign. An extension is then added to all encrypted documents, and a README text is placed in directories. The wallpaper is changed to the ransom demand message.

The attackers can customize the contents of the ransom note and the README file in the config file, which, once again, provides the malware with flexibility which allows it to operate as ransomware-as-a-service since different attackers can demand ransoms of various sums and provide custom instructions to victims.

Sodinokibi ransomware analysis

ANY.RUN provides the ability to watch the Sodinokibi in action and perform the ransomware analysis via an interactive virtual sandbox simulation.

sodiokibi execution process graph Figure 1: illustrates the processes launched by Sodinokibi during its life cycle.

workstation desktop after Sodinokibi infection Figure 2: Wallpapers with ransom message set by Sodinokibi

Sodinokibi execution process

Sodinokibi won't run malicious activity on systems where UI and keyboard languages are set to a specific value, such as Russian, Ukrainian, and 18 others. Although Sodinokibi is a "qualitative" type of malware, its execution, and system infection process, in general, is quite straightforward and similar to other ransomware - it decrypts files, erases shadow copies, and places ransom notes across the file system. Process tree also doesn't look very exciting because all main activities are provided by a single executable. For all infected files, the ransomware changes extensions to generated. The added extension is the same as an ID which is unique and made by combining the hash of the value given by CPUID instruction and the volume serial number. It should be noted that Sodinokibi will also try to encrypt files on network shares. After completion of the decryption process, the ransomware sets the background wallpaper to a ransom message.

Interestingly, the authors of Sodinokibi created a high-quality website available at the domain decryptor.top, where victims can use a trial decryptor and have the opportunity to decrypt three images for free. Besides the decryption function, this website provides information such as the countdown (after time runs out, the ransom amount will be set to 5 000 dollars), instructions on how to buy bitcoins, and where to send them as well as information about the decryption process. If decryptor.top is not available, there is a possibility for victims to visit its .onion clone through the Tor web browser.

How does Sodinokibi spread?

To infiltrate the machines of its victims, Sodinokibi takes advantage of quite some infection vectors, most of which are very similar to its predecessor - GandCrab.

The RAAS is known to utilize the CVE-2019-2725 vulnerability and use the RIG exploit kit. Additionally, Sodinokibi also spreads via compromised managed service providers. And, like icing on the cake, on top of the attack vectors mentioned above, this ransomware is often distributed in malicious spam campaigns.

Sodinokibi communication with C&C

Interestingly, while many ransomware needs to connect to C2 for exchanging encryption keys, for example Maze, Sodinokibi uses something called an asymmetric key scheduling algorithm.

It enables the RAAS to operate without any network connection and not giving the user any chance to get their hands on data that could help with file decryption. However, attackers can optionally establish a connection with the control server to retrieve general system data from infected machines by tweaking the config file.

System and user data then will be transmitted to a broad list of web domains, many of which look completely real and legal - possibly compromised WordPress websites, many of which can be included to hide the real C&C web address. In return, Sodinokibi can receive and read the response from the server, but it is not being saved or used in any way during the operation.

How to prevent Sodinokibi attacks?

While the use of vulnerabilities allows this ransomware to infected machines without active user actions, basic rules of online hygiene can still greatly decrease the probability of “catching” this virus.

In particular, not downloading attachments in suspicious emails or emails that arrived from unknown senders and keeping the macros disabled in Microsoft Office completely guarantees that one won’t be infected with Sodinokibi via a malicious spam email campaign.

How to get more information from Sodinokibi ransomware analysis?

Since crooks behind Sodinokibi offer decryption of three images for free, you can use the interactivity of ANY.RUN to take additional steps in your ransomware analysis. Open the website specified in a ransom note in the browser and follow all steps to decrypt images to get a bigger picture of a ransomware infection process.

Sodinokibi payment website Figure 3: Sodinokibi payment website

Conclusion

Since its introduction in 2019, thousands of computers were already infected with Sodinokibi, and this malware is continuing to be an ongoing danger.

Borrowing much of the functionality from already quite powerful GandCrab ransomware, Sodinokibi improves on it even further to become a real powerhouse of ransomware. Unfortunately, evidence suggests that this malware is developed by experienced cybercriminals who know how to build and distribute a virus. Its accessibility, thanks to malware as a service business model, makes it a real threat to businesses and individuals worldwide.

Thankfully, malware analysis services like ANY.RUN allow cybersecurity researchers to study such threats and prepare their defenses accordingly.

IOCs

IP addresses

No IP adresses found

Hashes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No hashes found

HAVE A LOOK AT

Adwind screenshot
Adwind
adwind trojan
Adwind RAT, sometimes also called Unrecom, Sockrat, Frutas, jRat, and JSocket, is a Malware As A Service Remote Access Trojan that attackers can use to collect information from infected machines. It was one of the most popular RATs in the market in 2015.
Read More
Agent Tesla screenshot
Agent Tesla
agenttesla trojan rat stealer
Agent Tesla is spyware that collects information about the actions of its victims by recording keystrokes and user interactions. It is falsely marketed as a legitimate software on the dedicated website where this malware is sold.
Read More
Ave Maria screenshot
Ave Maria
avemaria stealer trojan rat
Ave Maria malware is a Remote Access Trojan that is also called WARZONE RAT. Hackers use it to control the PCs of their victims remotely and steal information from infected PCs. For example, they can remotely activate the camera to take pictures of a victim and send them to a control server.
Read More
Azorult screenshot
Azorult
azorult trojan rat
AZORult can steal banking information, including passwords and credit card details, as well as cryptocurrency. This constantly updated information stealer malware should not be taken lightly, as it continues to be an active threat.
Read More
Crimson RAT screenshot
Crimson RAT
crimson rat trojan
Crimson is a Remote Access Trojan — a malware that is used to take remote control of infected systems and steal data. This particular RAT is known to be used by a Pakistani founded cybergang that targets Indian military objects to steal sensitive information.
Read More
Danabot screenshot
Danabot
danabot trojan stealer
Danabot is an advanced banking Trojan malware that was designed to steal financial information from victims. Out of the Trojans in the wild, this is one of the most advanced thanks to the modular design and a complex delivery method.
Read More