Geek's Advice

KOTI Ransomware makes personal files inaccessible by encrypting them

KOTI Ransomware (also known as Koti File Virus) is a malicious computer virus that encrypts personal or work files on Windows operating systems. It is the 226th extension variant of STOP/DJVU ransomware, which uses military-grade encryption method to make files inaccessible and add an extra .koti file extension after the original one. For example, a file called document.doc becomes document.doc.koti after the cyber attack. Following a successful attack, the ransomware drops ransom notes called _readme.txt in every folder that was affected by data encryption.

The ransomware uses a stealthy technique to get onto victim’s computer – it usually arrives along illegal downloads such as game or software cracks. During the data encryption procedure, the malicious ransomware showcases a fake Windows update screen to make the victim believe that there’s nothing wrong with the initial download. In addition, it disables Windows Task Manager, so that the victim could not view currently running processes and disable the virus.

In the meantime, the virus attempts to contact its Command&Control server to generate an unique encryption/decryption key and personal ID for the victim. If this connection fails, the virus uses offline key instead (same for all hosts with failed C&C connections).

Koti File Virus then begins scanning and encrypting files on all computer folders, bypassing essential OS data folders to keep the system running. It assigns additional file extension to mark affected files and creates a ransom note containing the personal ID to inform the victim about data encryption and possible recovery scenario.

It is important to note that this ransomware tends to modify Windows HOSTS file and prevent victim’s from accessing certain computer-related websites. In addition, it installs Azorult, a password-stealing malware on the system.

Ransomware aims to extort the victim

The primary aim of KOTI ransomware is to prevent the victim from accessing personal files, and force him/her to pay a specified ransom price in a certain cryptocurrency. The _readme.txt ransom note opens via default editor, Notepad, and contains a message from the cybercriminals. The crooks inform the victim that it is possible to restore encrypted files, but the victim must fulfill the attackers’ demand and pay them a ransom.

The note reads, “The only method of recovering files is to purchase .koti decrypt tool and unique key for you. This software will decrypt all your encrypted files.” The rest of the note informs that the attackers are willing to decrypt one file for free to prove that it is worth paying the ransom.

Speaking of the ransom price, Koti ransomware developers suggest 50% discount if the victim contacts them in three days (72 hours). This way, the ransom price is $490 in Bitcoin. If the victim contacts them later, the price rises to $980. Unlike similar viruses, this particular ransomware doesn’t have a payment website accessible via Tor browser. Instead, it suggests contacting the criminals via provided emails: helpmanager@mail.ch or alternative restoremanager@firemail.cc.

While we do understand that your data was important and that your primary goal now is to decrypt .koti files, we definitely do not recommend paying the ransom to cybercriminals. There are many reasons why you shouldn’t: crooks might not help you to recover the data, and by paying, you support the rising cyber crime industry. Instead of wasting your money this way, we recommend you to use it for your cyber security improvement and data backups.

You can successfully remove KOTI ransomware virus along with other malware it may have installed on your system (such as Azorult Trojan) using your anti-virus program. To repair damaged Windows system files, employ RESTORO.

Threat Summary

Ransomware distribution explained

Ransomware-type viruses typically spread via:

• Malicious spam campaigns. Nowadays, cyber criminals can modify documents such as DOC or PDF to contain malicious macros or JavaScript to download and execute malware from external source as soon as the document is opened. Such files then are renamed into something like “invoice” or “report” and sent to work emails, urging the victim to open them as soon as possible. Such malicious campaigns often have words such as “URGENT,” “Confidential” or “IMPORTANT” in their subjects.
• Compromised websites. If hackers manage to break into a certain website and exchange downloadable files with malicious ones, they can speed up the malware distribution rapidly. Therefore, our suggestion is to have real-time protection enabled and save files to your computer instead of directly opening it. This way, you can set your antivirus to scan it first.
• Infectious downloads. Illegal downloads such as game cracks, movies and copyrighted music albums are very popular downloads, and hackers tend to pack them with malicious executables.
• Exploitable vulnerabilities in outdated software current on the target hosts. Please keep all your software, including operating system version up-to-date at all times. Software updates are issued to address not only various functionality improvements, but also security issues.

When it comes to STOP/DJVU ransomware variants such as KOTI file virus, MZLQ, SQPC, MPAL, QEWE and others, they all await victims in software cracks and similar illegal downloads. Many victims report downloading it along Adobe Photoshop Cracks, KMSpico and similar programs.

KOTI ransomware removal explained

You must remove KOTI ransomware to protect your privacy and security. To cleanse the system from the said virus and additional malware that it may have dragged into the system, we suggest using a powerful malware removal tool, such as RESTORO (includes Avira scanning engine). In addition, it can be used for fixing damaged system files, such as the affected HOSTS file.

You can find KOTI file virus removal guide down below. It was prepared by our experts and supplied with self-explanatory images to guide you through the process quickly.

PROFESSIONAL TIP. Do not forget to change your passwords after removing the malware from your system.

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

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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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Alternative software recommendations

Malwarebytes Anti-Malware

Removing spyware and malware is one step towards cybersecurity. To protect yourself against ever-evolving threats, we strongly recommend purchasing a Premium version of Malwarebytes Anti-Malware, which provides security based on artificial intelligence and machine learning. Includes ransomware protection. See pricing options and protect yourself now.

System Mechanic Ultimate Defense

If you're looking for an all-in-one system maintenance suite that has 7 core components providing powerful real-time protection, on-demand malware removal, system optimization, data recovery, password manager, online privacy protection and secure driver wiping technology. Therefore, due to its wide-range of capabilities, System Mechanic Ultimate Defense deserves Geek's Advice approval. Get it now for 50% off. You may also be interested in its full review.

Disclaimer. This site includes affiliate links. We may earn a small commission by recommending certain products, at no additional cost for you. We only choose quality software and services to recommend.

FAQ

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.