Koti is the 226th Djvu ransomware family member that emerged in the middle of May 2020
Koti ransomware is the latest version of the infamous Djvu family of crypto-malware. Resurfaced in the middle of May 2020, it takes the 226th position in the list of STOP/Djvu variants and stands in line with .mpal, .sqpc, and .mzlq entries. Alike its predecessors, Koti ransomware uses RSA encryption model to lock non-system files and uses a standard _readme.txt ransom note. Besides, it is using the .koti file extension to separate encrypted documents, pictures, videos, photos, databases, archives, and other data from the others.
The criminals behind Koti ransomware are using the helpmanager@mail.ch and restoremanager@firemail.ch emails for contacts. Apparently, they are using the same extortion scheme as the victims are demanded to pay the $980 in Bitcoins as a ransom for a decryptor, though promise to double down the price if the payment comes within 72 hours.
| Name | Koti |
| Family | The infamous group of STOP / Djvu ransomware |
| Detection | May 2020. The first ransomware sample has been uploaded into the official Emsisoft's support[1] site |
| Classification | The Koti virus falls for the ransomware or file-encrypting malware group |
| Version number | This ransomware is currently the latest djvu version, which stands 226th in the list |
| File marker | The viruses uses .koti file extension to mark locked files |
| Encryption model | RSA |
| Distribution | This extortionist is typically distributed via malicious e-mail message attachments, unprotected RDP ports, P2P networks, or pirated software |
| Other traits | One the payload is launched, the ransomware locks files and drops a ransom note _readme.txt, which contains a detailed guide on how to pay the ransom |
| Payment conditions | Criminals urge victims to pay $490 if the payment is transferred within 72 hours. If the victim delays the payment, the price is doubled and reaches $980. The only currency accepted – Bitcoin. |
| Detection | It is not possible to detect malicious ransomware files manually. The detection and removal of the intruder is possible with a professional AV engine. |
| Damage | The ransomware removal does not ensure full recovery of the affected system files. To fix Windows registry entries, boot files, and other core components, use FortectIntego utility. |
Koti ransomware has been expected to manifest in May, since Djvu ransomware is infamous for its regular release of renewed versions. The first sample of this virus has been uploaded into Emsisoft's support forum where the victim presented the _readme.txt file accompanied by a file locked by .koti file extension.
A close investigation proved the evidence of Koti to be rooted from Djvu ransomware family. It uses a similar base for the distribution, infiltration, encryption, and extortion. According to researchers, its payload is typically distributed via obfuscated spam email attachments or pirated software. Besides, it may also be used for spreading the infamous AZORult trojan as a secondary payload.
Upon successful infiltration, the ransomware begins the first phase of the deployment. The malware settles down multiple boot processes, launches PowerShell to delete Shadow Volume Copies, and disables the AV engine to evade immediate removal. Koti ransomware may also corrupt Windows host files and establish firewall access to security-related forums and websites containing guidelines on how to remove the ransomware and recover damaged files.
This cyber infection is not a threat to mess with as it may cost you a permanent file loss. The best solution for its victims is a full Koti ransomware removal using a program like SpyHunterCombo Cleaner, MalwarebytesMalwarebytes, or another professional antivirus tool. This file-encrypting virus can not only encrypt the data on the host machine, but also plant multiple malicious files, compromise the system severely, and download the Azorult trojan as a secondary payload. Consequently, criminals may get access to your personally identifiable information (PII)[2], including saved passwords, banking information, login details, etc.
The changes that the Koti ransowmare initiates can hardly be overlooked. Initially, it starts running malicious processes within Task Manager, which is why CPU usage may increase significantly. The most obvious sign indicating ransomware infection is the .koti file extension appended to the pictures, archives, Microsoft Office documents, videos, and other non-system files.
As a final point, the virus creates a _readme.txt ransom note on the random system's folders and the desktop. The note contains the detailed instructions on how to contact ransomware developers and how to transfer the ransom. In short, the victims are expected to contact the crooks via the helpmanager@mail.ch and restoremanager@firemail.ch emails and transmit a ransom, which varies from $480 to $980 in Bitcoins.
ATTENTION!
Don't worry, you can return all your files!
All your files like photos, databases, documents and other important are encrypted with strongest encryption and unique key.
The only method of recovering files is to purchase decrypt tool and unique key for you.
This software will decrypt all your encrypted files.
What guarantees you have?
You can send one of your encrypted file from your PC and we decrypt it for free.
But we can decrypt only 1 file for free. File must not contain valuable information.
You can get and look video overview decrypt tool:
hxxps://we.tl/t-EEHXgjySek
Price of private key and decrypt software is $980.
Discount 50% available if you contact us first 72 hours, that's price for you is $490.
Please note that you'll never restore your data without payment.
Check your e-mail “Spam” or “Junk” folder if you don't get answer more than 6 hours.To get this software you need write on our e-mail:
helpmanager@mail.chReserve e-mail address to contact us:
restoremanager@firemail.chYour personal ID:
Indeed, criminals who promote this ransomware virus expects to extort as much money as possible. However, our biggest piece of advice is to remove Koti ransomware in the first place and then try to recover files using third-party software. Do not get scared by claims that you will lose the files permanently by running an AV scan. Criminals use such and similar scare tactics to catch victims on the hook.
After full Koti ransomware removal, you can start thinking about a recovery of the encrypted data. Since Djvu is one of the largest ransomware families on the surface, cybersecurity experts have invested much time to develop a free decryption software. At the moment, the Dr. Web Rescue Pack is probably the most reliable tool for retrieving files. However, not all Djvu variants can successfully be crashed by this tool. In case of a failure, try alternative data recovery methods listed at the end of this article.
Methods that criminals engage for ransomware distribution
Experts from LosVirus.es[3] provided us with their findings on the methods that cybercriminals are typically using to spread ransomware infections. According to them, the most popular medium to spread malicious payloads is spam. Hackers craft reliable-looking email messages mimicking the style of various companies (DHL, FedEx, White House, Red Cross, etc.) and disguise ransomware under infected “order confirmations” or similar attachments.
Nevertheless, spam email attachments are not the only ransomware transmitters. Crooks often exploit vulnerable Remote Desktop Protocol (RDP) network connections and use brute-force attacks to infect target systems. The TCP port 3389 is one of the most frequently exploited vulnerabilities allowing criminals to easily attack potential victims. P2P networks, illegal or hacked websites, software cracks, keygens, and other online content that can easily be exploited by hackers.
Thus, having an anti-virus program installed is not sufficient to protect the system from malware. A user's consciousness is equally important. First of all, people should start taking care of the backups, at least backup the most important data, such as documents or family photos. Second of all, think twice before downloading illicit software or visiting potentially dangerous domain.
Use a professional AV engine to remove Koti ransomware
Koti ransomware removal requires the usage of a powerful antivirus program. If you've ever dealt with a ransomware-type virus, you should know that manual removal is not possible under any circumstances. File-encrypting viruses are built in a very comprehensive manner as they infiltrate tens of malicious files in diverse system's places to make Windows conform to malicious commands.
Before any attempts to remove Koti ransomware, we recommend copying encrypted files to alternative storage, bet it USB flash drive or cloud. That's a necessary precautionary measure to prevent permanent loss of files encrypted by .koti file extension.
For a full Koti removal use SpyHunterCombo Cleaner, MalwarebytesMalwarebytes or an alternative AV engine of your preferences. After that, try to recover the data using the recovery solutions provided below.
Did this guide help?
Be the first to comment