Geek's Advice

Remove XCMB Ransomware Virus (DECRYPT .XCMB FILES)

XCMB ransomware is a dangerous file-encrypting malware that belongs to the notorious STOP/DJVU ransomware group. This virus is known to operate by encrypting the entire files contained in any computer it infiltrates and completes the process by appending .xcmb extension to each file name as a way of marking it out. E.g. a file hitherto saved as 1.jpg becomes 1.jpg.xcmb and same format is replicated on other files. While the process is still ongoing, a ransom note known as _readme.txt will be dropped in all the folders. The ransom note contains a directive from the cybercriminals instructing the victim to pay a certain amount of money as ransom in exchange for XCMB decryption tool. 

They will claim that the only way to recover the encrypted files is through a decryption tool they will make available to the victim once they make a payment. To facilitate the payment process, they will notify the victim about their email addresses (i.e. manager@mailtemp.ch and helpsupportmanager@airmail.cc) already forwarded in the ransom note. 

There are also terms of payment the victim would be expected to comply with. For instance, they will emphasize that if the victim responds to their demand in 72 hours or less, he will be entitled to a 50% discount. In other words, instead of paying the full ransom fee of $980, he would now pay $490. However, once the 3 days/72 hours grace elapses, only the full ransom demand would be acceptable.  

Peradventure, the victim decides to reach out to them, he will be notified that ransom payment can only be made through cryptocurrency, whereby the cryptocurrency equivalence of the ransom demand would have to be transferred to a particular wallet address they would make available. They chose this option obviously to cover their tracks and prevent possible tracing by law enforcement agents. In order to encourage the victim to comply, they may suggest that excerpts of the encrypted files should be forwarded to them for test decryption. They would also emphasize that such excerpt must not contain any message that could be perceived as important to the victim.

Regardless of the situation, our cybersecurity experts recommend that it is best for victims to follow FBI guidelines which generally prohibit any form of ransom payment. This recommendation is based on the following reasons: 

• Paying ransom does not guarantee that your encrypted files will be restored
• When you pay ransom, you’re encouraging cybercriminals since it will become profitable
• With more ransom money in their disposal, they would be able to employ more hands and broaden their threat

Also note that the virus is known to release information stealing Trojans like VIDAR, AZORULT etc. on the compromised computer. Such Trojans can covertly steal personal details including browser-saved passwords, banking details, cryptocurrency wallets, software login credentials, browsing history etc. Once they can obtain such sensitive details, further blackmail can’t be ruled out.  

Anyone that finds himself at the receiving end of this malware should endeavor to remove XCMB ransomware virus as soon as possible. You can do this by scanning an active antivirus while your computer is in Safe Mode with Networking set up. If you do not have an antivirus software yet, we simply recommend INTEGO Antivirus– you can read its full review here. As an additional step, you may want to download RESTORO and try to repair virus damage on Windows OS files.

Ransomware Summary

REMOVE MALWARE & REPAIR VIRUS DAMAGE

Ransomware distribution methods you should be wary of

On a general perspective, most victims’ computer systems often become compromised with STOP/DJVU variants such as XCMB virus following attempts at downloading malicious torrents. Note that these variants of malware are known to hibernate in unwholesome software contents such as pirated software copies, “cracks” or key generators. Therefore, these sorts of products should be avoided at all costs. Over the years, victims of ransomware have reported that their computer systems became compromised after visiting online torrents libraries. Some of the most popular software contents the cybercriminals often make use of, include the following: 

• Cubase;
• Corel Draw;
• Tenorshare 4ukey;
• Internet Download Manager;
• Opera browser;
• Fifa 20;
• VMware Workstation;
• Adobe Photoshop;
• Adobe Illustrator;
• League of Legends;
• AutoCad;
• KMSPico (illegal Windows activation tool).

At this point, it has become evident that users should avoid visiting online torrents libraries to protect their computer systems from malware attacks. It is not a smart idea by trying to obtain copyrighted software contents at little or no costs, considering the risks attached to it. Ransom demands can be outrageous and malware attacks can equally be disruptive. On the contrary, by paying the legitimate cost as advertised by the original content producers, you’re encouraging them to remain profitable which in turn will lead to more products. In addition to that, you will not be at risk losing sensitive data, money or having your work/activities disrupted. 

Aside online torrent libraries, another prolific way of spreading malware is through malicious email attachments. Cybercriminals make use of this option by sending out “convincing” and legitimate looking emails. They often leverage PDF, DOCX and XLS platforms because they enable macro functions as well as JavaScript (they are perfect for downloading of payloads that can be transferred to a computer system).  

The biggest challenge is that trying to decipher if a particular email is legitimate or carrying a malware can be quite difficult. The cybercriminals have become more sophisticated in recent times and are now known to impersonate popular brands like Amazon, UPS, FedEx, eBay etc. They even go further to use enticing labels such as Tracking Details, Invoice or Order Summary etc. On the other hand, they may even decide to make use of email spoofing techniques to hide the originating address. To be on the safe side, users are advised to abstain from opening emails indiscriminately. If you’re not expecting a particular email then it may not be wise to open such when it lands in your inbox or scam. 

For those that are victims of STOP/DJVU ransomware already, it is advisable to refrain from visiting websites that claim to provide decryption services because such do not exist at the moment. Also note that cybercriminals often make use of fake STOP/DJVU decryptors to spread other types of ransomware. Some victims may argue they have nothing else to lose but that’s not true because such fake tools can lead to double encryption.

What happens during STOP/DJVU ransomware attack

For victims that may be wondering about the extent to which their computer system may have been compromised during the XCMB ransomware attack, this section is for you. However, the malware is known to launch build.exe or build2.exe as well as winupdate.exe. The latter is what displays the fake Windows screen. Afterwards, it will connect to https[:]//api.2ip.ua/geo.json while saving the result in geo.json file. Once it gets to this stage, it will start gathering every available piece of information about the compromised computer such as its geolocation, time zone, zip code, latitude and longitude. Additionally, the virus saves some information about the computer such as computer name, operating system version as well as hardware and software details. These vital pieces of information will be forwarded to their server. 

Below are some typical examples of geo.json file.

You can also see an example of information.txt file below.

The computer’s geolocation will be profiled against their encryption-encrypted nations which are Russia, Belarus, Syria, Tajikistan, Uzbekistan, Armenia, Kyrgyzstan, Ukraine and Kazachstan. If it shows positive to any of the listed countries, it will abort its mission but if otherwise, it will proceed to the next stage. 

Having scaled the first hurdle, the ransomware will then extract online encryption key from their server, which would be compiled in addition with the victim’s ID and sent to bowsakkdestx.txt file and to PersonalID.txt file. 

Here is an example of how these files appear. 

Peradventure the virus couldn’t extract an online encryption ID, it will resort to the use of an offline encryption ID. The difference between the two is that while online ID makes of use of a unique key that is peculiar to each victim, the offline one rather uses a uniform one. You can detect if an offline key was used if it has t1 characters appearing at the end of the personal ID. Use of offline keys means there is a higher chance of decrypting .XCMB files someday. 

More information on this is provided in this guide on decrypting/repairing files affected by STOP/DJVU variants.

At this point, malware will commence full data encryption by scanning the entire folders and encrypting them with Salsa20 before locking the encryption key with RSA-2048 key. It will also mark the files with additional extensions.

In the image below is a screenshot of _readme.txt ransom note that are usually dropped in each folder. 

The next thing it does is to delete all Volume Shadow Copies by making use of the Command Prompt as displayed here:  vssadmin.exe Delete Shadows /All /Quiet

Afterwards, it will add certain domains to the Windows HOSTS file which would be sent to a localhost IP. This move effectively bars the victim from accessing any of the blacklisted websites. DNS_PROBE_FINISHED_NXDOMAIN error message would appear on the screen any time the victim tries to open any of the websites. The reason why the cybercriminals do this is to prevent the victim from getting help online. 

Remove XCMB Ransomware Virus and Recover Your Files

It is important to reiterate that victims should as a matter of necessity, report any incidence of malware attack to the appropriate authorities, and of course, also remove the XCMB ransomware virus as soon as they can. You can take the steps listed below on how to go about it. 

You can also make use of the guide provided here on how to set up your computer in Safe Mode with Networking Option. This option is the most suitable because it will limit certain functions thus enabling the antivirus software to work effectively in removing the malware. You can always make use of INTEGO Antivirus or any other strong and reliable one. Next step we recommend doing is to download RESTORO and try it to repair virus damage on Windows OS files.

Once you have succeeded in removing the XCMB ransomware virus, it is recommended that you should take the following steps:  

• Any form of ransomware attack should be reported to the relevant local law enforcement agencies.
• Leverage any of your backup devices to restore your lost files. However, you must ensure that the virus is completely removed before attaching any external storage device to your compromised computer system.
• You may consider learning how to decrypt/repair files that were encrypted by certain variants of STOP/DJVU virus.
• It is very important that you should change all passwords that were associated with the compromised computer. Such passwords include the ones that were saved on your browser, telegram, software contents etc.

In summary, you should avoid accessing online torrents libraries, indiscriminate opening of emails/email attachments, and also ensure to install a strong and reliable antivirus in your computer system and update it always. 

OUR GEEKS RECOMMEND

Our team recommends a two-step rescue plan to remove ransomware and other remaining malware from your computer, plus repair caused virus damage to the system:

STEP 1. REMOVE AUTOMATICALLY WITH ROBUST ANTIVIRUS

REMOVE & PROTECT WITH INTEGO

Get INTEGO ANTIVIRUS for Windows to remove ransomware, Trojans, adware and other spyware and malware variants and protect your PC and network drives 24/7.. This VB100-certified security software uses state-of-art technology to provide protection against ransomware, Zero-Day attacks and advanced threats, Intego Web Shield blocks dangerous websites, phishing attacks, malicious downloads and installation of potentially unwanted programs.

Use INTEGO Antivirus to remove detected threats from your computer.

Read full review here.

STEP 2. REPAIR VIRUS DAMAGE TO YOUR COMPUTER

DOWNLOAD RESTORO

RESTORO provides a free scan that helps to identify hardware, security and stability issues and presents a comprehensive report which can help you to locate and fix detected issues manually. It is a great PC repair software to use after you remove malware with professional antivirus. The full version of software will fix detected issues and repair virus damage caused to your Windows OS files automatically.

RESTORO uses AVIRA scanning engine to detect existing spyware and malware. If any are found, the software will eliminate them.

Read full review here.

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Norbert Webb

Norbert Webb is the head of Geek’s Advice team. He is the chief editor of the website who controls the quality of content published. The man also loves reading cybersecurity news, testing new software and sharing his insights on them. Norbert says that following his passion for information technology was one of the best decisions he has ever made. “I don’t feel like working while I’m doing something I love.” However, the geek has other interests, such as snowboarding and traveling.