RYK (.RYK) ransomware virus - removal and decryption options

What kind of malware is RYK?

There are many ransomware-type computer infections available online, including RYK, which was discovered by MalwareHunterTeam. This is a new variant of RYUK Ransomware.

RYK encrypts data using a cryptography algorithm, thereby rendering files stored on a computer unusable. It appends the ".RYK" extension to each encrypted file, thus renaming all affected files. For example, "1.jpg" becomes "1.jpg.RYK". RYK also places a "RyukReadMe.txt" text file (ransom-demand message) in every folder that contains encrypted files.

Screenshot of files encrypted by RYK (".RYK" extension):

RYK ransom note overview

The ransom message within "RyukReadMe.txt" is from RYK developers who inform victims that all data has been encrypted using a strong cryptography algorithm, however, the type of algorithm used (symmetric or asymmetric) is not specified.

They state that encrypted backups and shadow copies have also been encrypted and that using the F8 key (and other methods) will not help and might even do more damage (this function key is often used to enter the Windows startup menu while booting the Windows Operating System and can also be used to access Windows recovery system).

RYK developers also state that only they can provide victims with a decryption tool, and no other tools are capable of decryption. In summary, they make it clear that no other party can help those with computers infected with RYK. These cyber criminals also warn users that shutting down or restarting a computer might cause damage or data loss.

They urge people not to delete or rename the "RyukReadMe.txt" text files. RYK developers offer free decryption of two files to prove decryption is possible and in an attempt to give the impression that they can be trusted.

To decrypt the remaining data, users must contact them via the charlstonparkwji@protonmail.com or huntingdonu@tutanota.com email address. Once contacted, they will send a Bitcoin wallet address for the ransom payment (to be made in a cryptocurrency).

Do not contact RYK developers under any circumstances. They use cryptographies that generate unique decryption keys (and store them on remote servers controlled only by them).

In this way, they can blackmail victims, since there are no other (free) tools capable of cracking RYK ransomware encryption. Note that cyber criminals usually ignore victims even if their ransom demands are met. The best solution in these cases is to use an existing backup and restore files from there.

Ransomware in general

There are many ransomware-type viruses online, such as Forma, Doubleoffset, and Gerber. All infections of this type are very similar and serve the same purpose: to encrypt data and keep it in that state until ransom demands are met.

The main differences are ransom size (cost of decryption) and cryptography algorithm used to encrypt data. Decryption without the involvement of ransomware developers is usually impossible, unless their program is not fully developed, contains bugs/flaws or other important deficiencies.

Therefore, maintain regular backups and keep them stored on remote servers or unplugged storage devices.

How did ransomware infect my computer?

It is not known exactly how cyber criminals promote RYK ransomware, however, in most cases, infections of this type are distributed through spam campaigns, trojans, fake software updaters, and other untrustworthy software download sources. Spam campaigns are used to proliferate these infections by employing emails that contain malicious attachments.

These can be Microsoft Office documents, PDFs, archive files, executables, and so on. By opening these attachments, people are often tricked into downloading and installing computer infections, including ransomware.

Trojans are computer infections (malicious programs) that are used to proliferate other infections (if installed, they cause chain infections). Untrustworthy software download sources such as peer-to-peer networks (eMule, torrents, and so on) usually present malicious files (often executables) as legitimate files.

Freeware download websites, file hosting websites and other similar software download sources are also used to proliferate viruses. Using these untrustworthy sources, cyber criminals trick people into downloading and installing malicious programs.

Another common way to proliferate these viruses is using fake software updaters - They infect systems by exploiting bugs/flaws of installed (outdated) software or downloading and installing malicious programs rather than the updates, fixes, etc.

How to protect yourself from ransomware infections?

The key to computer safety is caution. To prevent computers infection, browse the web, download, install and update software with care. Do not open attachments or web links that are presented in emails received from unknown/unidentified/suspicious email addresses.

If an email does not relate to you, ignore it. Do not use third party downloaders, installers or other such tools to download or install software. These are often used to proliferate rogue apps or other unwanted software (potentially, malicious).

Never use unofficial tools to update installed software (or the operating system). This might lead to installation of unwanted software or even high-risk computer infections.

The best way to keep your software up-to-date is to update it using tools and/or functions that are provided by official developers only. Reputable anti-virus/anti-spyware software can prevent computer infections, and we recommend that you have this software installed and active.

If your computer is already infected with RYK, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate this ransomware.

Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data ("RyukReadMe.txt")

Text presented in RYK ransomware text file ("RyukReadMe.txt"):

Your network has been penetrated.

All files on each host in the network have been encrypted with a strong algorithm.

Backups were either encrypted
Shadow copies also removed, so F8 or any other methods may damage encrypted data but not recover.

We exclusively have decryption software for your situation.
More than a year ago, world experts recognized the impossibility of deciphering by any means except the original decoder.
No decryption software is available in the public.
Antiviruse companies, researchers, IT specialists, and no other persons cant help you encrypt the data.

DO NOT RESET OR SHUTDOWN - files may be damaged.
DO NOT DELETE readme files.

To confirm our honest intentions.Send 2 different random files and you will get it decrypted.
It can be from different computers on your network to be sure that one key decrypts everything.
2 files we unlock for free

To get info (decrypt your files) contact us at
CharlstonParkwji@protonmail.com

annarummoWellington91@protonmail.com

imatprophav1982@protonmail.com

papinsdasun1982@protonmail.com

krystyna_trapp1989@protonmail.com

dfvdv@tutanota.com
or
Huntingdonu@tutanota.com

LakelynnMaske@protonmail.com

wahabigreen@tutanota.com

cestidemet1983@protonmail.com

keelyjankowski1992@protonmail.com

jkjbg@protonmail.com

escirepi1974@protonmail.com

You will receive btc address for payment in the reply letter

Ryuk

No system is safe

Update January 23, 2019 - RYK's developers have released another variant of this ransomware which also known as Cryptor 2.0. This variant generates a differently named text file ("ReadMe.txt") and provides different email addresses. The ransom-demanding message and file extension remain the same.

Screenshot of updated RYK's variant (Cryptor 2.0) text file:

Text presented within this file:

Your network has been penetrated.

All files on each host in the network have been encrypted with a strong algorithm.

Backups were either encrypted
Shadow copies also removed, so F8 or any other methods may damage encrypted data but not recover.

We exclusively have decryption software for your situation.
More than a year ago, world experts recognized the impossibility of deciphering by any means except the original decoder.
No decryption software is available in the public.
Antiviruse companies, researchers, IT specialists, and no other persons cant help you encrypt the data.

DO NOT RESET OR SHUTDOWN - files may be damaged.
DO NOT DELETE readme files.

To confirm our honest intentions.Send 2 different random files and you will get it decrypted.
It can be from different computers on your network to be sure that one key decrypts everything.
2 files we unlock for free

To get info (decrypt your files) contact us at
DejackomeAjna@protonmail.com
or
ElmersVictoria@tutanota.com

You will receive btc address for payment in the reply letter

Ryuk

No system is safe

Another variant of the ransom demanding message created by RYK ransomware - RyukReadMe.txt:

Text presented in this variant:

Your network has been penetrated.
All files on each network host have been encrypted with a strong algorithm.
Backups were encrypted too.

Shadow copies also removed, so F8 or any other methods may damage encrypted data but not recover.
Only we have exclusive decryption software, suitable for your situation.

More than a year ago, world experts recognized the impossibility of such encryption deciphering by any means except the original decoder.
No decryption software is available in the public.
Antivirus companies, researchers, IT specialists, and any other persons cannot help you to decipher the data.

Decryption takes from ten minutes up to several hours.
It is performed automatically and doesn't require from you any actions except decoder launching.

DO NOT RESET OR SHUTDOWN SYSTEM — files may be damaged.
DO NOT DELETE readme files.

To confirm our honest intentions. Send 2 different random files and you will get them back decrypted.
It can be from different computers on your network to be sure that one key decrypts everything.
We will unlock 2 files for free.
To get info (decrypt your files) contact us a
BoganyRosina@protonmail.com
or
NaborBrice1990@protonmail.com

You will receive btc address for payment in the reply letter

Ryuk
No system is safe

Another variant of a ransom-demanding message created by RYK ransomware - RyuReadMe.html:

Text presented in this html file:

CilibertoGeorgiana1992@protonmail.com

rumguygcarhell1979@protonmail.com

tamesepo1980@protonmail.com

loybranunun1975@protonmail.com

erenomen1979@protonmail.com

backnabanney1983@protonmail.com

prefexdocve1989@protonmail.com

otostehos1970@protonmail.com

subsazimi1970@protonmail.com

kirsninmaino1977@protonmail.com

distwilmufor1989@protonmail.com

reelsraserro1970@protonmail.com

bubgiasvilfa1985@protonmail.com

abcorviman1981@protonmail.com

hemulnina1974@protonmail.com

isadora_mashburn1987@protonmail.com

anfreesextuo1982@protonmail.com

rotenakge1989@protonmail.com

Teara.Baker.1977@protonmail.com
DevinoCandence96@protonmail.com

vadocpuce1975@protonmail.com
futamenlooo1981@protonmail.com

hostthingbourbuo1973@protonmail.com
bunakade1970@protonmail.com

chris-morris-1976@protonmail.com
tasha-williams.91@protonmail.com

gaetwelsenba1983@protonmail.com

enexunon1979@protonmail.com

lundcedrick@protonmail.com

buricoume1976@protonmail.com

kassulke_dora@protonmail.com

marks_arno@protonmail.com

zandra_simone1995@protonmail.com

olgearreabo1989@protonmail.com

profhandgomo1989@protonmail.com

Ryuk

balance of shadow universe

Update 21 June, 2019 - Cyber criminals have recently released an updated version of this ransomware. The new variant is implemented with a filter allowing cyber criminals to distinguish certain systems and decide whether to encrypt data or not. It is designed to check victim's IP address and computer name. If the Internet IP address contains 10.30.4, 10.30.5, 10.30.6, or 10.31.32 string, then the files will not be decrypted. Same goes for computer's name. If the name includes at least one of the listed strings (MSK, Msk, SBP, Spb, msk, spb), then data will also be left untouched.

Update November 10, 2020 - The latest variant of RYK ransomware doesn't provide any of cyber criminals' email addresses. Instead, users are given a Tor link leading to a website that contains a contact form.

Screenshot of the said website:

Yet another example of an HTML file dropped by RYK ransomware:

Text presented within:

[contact]

INSTRUCTION:
1. Download tor browser.
2. Open link through tor browser: hxxp://htv4omqldafxwhum7ya3m37o3zcbo2d7kidcpgvp6lky62gi6czx6iqd.onion
3. Fill the form, your password: -
We will contact you shortly.
Always send files for test decryption.
[OK]

Ryuk

balance of shadow universe

RYK ransomware removal:

Instant automatic malware removal:

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Removal and file recovery procedure

If your files are encrypted with a new extension and a ransom note has appeared, you've been hit by ransomware. Don't pay. The procedure below works in order: contain the infection, identify the variant, remove the ransomware itself (so anything you restore doesn't get re-encrypted), and try to recover files using free decryption tools, Windows Volume Shadow Copies, or backups. Run a full system scan with Combo Cleaner to remove the infection - then move on to file recovery.

Common ransomware behaviors

VisibleEncrypts your files and renames them

The ransomware reads each file, encrypts the contents with the attacker's public key, and writes the encrypted bytes back to disk. Most variants also rename the file by appending a new extension - .net, .locked, .crypt, .lockbit, .djvu, etc. Without the matching private key, the encrypted files cannot be opened normally. Recovery depends on a free decryption tool, a recoverable Volume Shadow Copy, or a clean backup.

VisibleDrops a ransom note in every encrypted folder

A text or HTML file (usually named HOW_TO_DECRYPT.txt, README.txt, _readme.txt, or similar) is placed in every folder that contains encrypted files. The note explains the situation, lists a payment amount in cryptocurrency, gives a deadline, and provides a contact email or .onion site. Save the note - don't delete it. Its exact wording, the email address, and the bitcoin wallet are how you identify the variant in the next phase.

VisibleReplaces the desktop wallpaper

Many ransomware variants change the Windows wallpaper to a black or red image with the ransom message and instructions. The wallpaper is just a visual scare tactic - it doesn't add any actual capability and reverts to normal once the ransomware is removed. Photograph it before removal in case the contact details are useful for variant identification or for reporting to authorities.

HiddenDeletes Volume Shadow Copies

One of the first things modern ransomware does after launching is run vssadmin delete shadows /all /quiet to wipe Windows' built-in Volume Shadow Copies - the snapshots that Previous Versions and System Restore rely on. Some ransomware doesn't fully succeed (especially on systems where the user lacks full admin rights), leaving partial shadow copies recoverable. Phase 4 step 11 covers how to check what survived.

HiddenDisables Windows Defender and other security tools

Before encrypting, the ransomware tries to silence anything that could alert you or block it - Windows Defender real-time protection, third-party antivirus services, backup agents (Veeam, Acronis), and sometimes the Windows Event Log service. It often modifies Group Policy or registry keys to keep these off after reboot. Phase 3 step 9 explicitly turns Tamper Protection back on so the next ransomware attempt can't repeat the trick.

HiddenSpreads laterally to other PCs on the network

Network-aware ransomware (LockBit, Conti, BlackCat, Akira families) doesn't stop at the first machine. It scans for SMB shares, mapped drives, and other PCs on the same network, then encrypts whatever it can reach. On Windows domains, a single compromised user with admin rights can lead to all-domain encryption. This is why Phase 1 step 2 disconnects the network as the very first action - it stops the spread immediately.

HiddenSteals data before encrypting (double extortion)

Modern ransomware (LockBit, BlackCat / ALPHV, Akira, Cl0p, Royal) almost always exfiltrates data before encrypting. The attacker then runs a "double extortion" play: pay the ransom for decryption, plus pay again to prevent the stolen data from being leaked on the group's leak site. Paying the first ransom does not get the leaked data back - assume that anything the ransomware could read was uploaded. This is one more reason not to pay: the data is already out.

Tools you'll need

Combo Cleaner Antivirus 7-days free trial

Recommended primary scanner. VB100 certified. Removes the ransomware infection so file recovery doesn't get re-encrypted.

Microsoft Defender Offline Free · built-in

Built into Windows. Scans before Windows fully loads to catch persistence the running scanners miss.

Microsoft Safety Scanner (MSERT) Free

Microsoft's free on-demand scanner. Always-current signatures - the binary expires every 10 days.

ID Ransomware Free · web

Upload a ransom note and a sample encrypted file - identifies the variant family and tells you whether a free decryptor exists.

No More Ransom Project Free · web

Joint project of Europol, Dutch Police, and security vendors. Free decryption tools indexed by ransomware family.

Shadow Explorer Free

Browse Windows Volume Shadow Copies as a normal file tree - useful when ransomware partially failed to delete them.

Recuva Free

Deleted-file recovery. Long-shot for ransomware - only helps if the variant deleted unencrypted originals before encrypting copies.

Phase 1~ 5 min

Don't pay & contain

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1

Don't pay the ransom

1 min · read⚠ Do not skip

Paying the ransom does not guarantee you'll get your files back. Major ransomware response studies consistently show that a meaningful percentage of paying victims either receive a non-working decryptor, only partial decryption, or no decryptor at all. Beyond that:

• Paying confirms you as a willing target - re-attack rates within 12 months are high
• Several ransomware groups have been sanctioned (US OFAC, UK OFSI). Paying these groups may be illegal under sanctions law in your country
• The ransom funds the next attack - on you or someone else
• Modern ransomware almost always exfiltrates data first, so paying doesn't get the leaked data back. Assume anything the malware could read was uploaded
• Decryptors, even when they work, often leave files corrupted because the encryption itself was buggy or rushed

The path below tries every legal, free recovery option first. Pay only as an absolute last resort, after consulting a lawyer and your country's cyber crime authority.

2

Disconnect from the network and log out of cloud storage

2 minNo tool needed

Pull the Ethernet cable and turn off Wi-Fi on the affected PC. If multiple computers share the network, do the same on every machine you suspect could be affected, including any servers and NAS units.

Then sign out of cloud storage clients (OneDrive, Dropbox, Google Drive, iCloud) from their app settings. If you can, pause the sync. Some ransomware uses the running sync client to push encrypted versions over your clean cloud copies.

Why this matters

Modern ransomware spreads laterally across SMB shares, mapped drives, RDP, and reachable network neighbors. Disconnecting stops the spread the moment you do it. Logging out of cloud sync clients prevents the ransomware from encrypting the cloud copies of your files via the sync API.

3

Unplug external drives and USB storage

1 minNo tool needed

Safely eject any external drives, USB sticks, SD cards, and network-attached storage shares - then unplug them. If a drive was connected when the ransomware ran, the files on it may already be encrypted, but unplugging stops further damage.

Critically: don't reconnect any drive (including your most recent backup) to this PC until the ransomware is removed in Phase 3. Reconnecting an external backup to an actively-infected PC is the most common way that backup gets encrypted too.

Phase 2~ 5 min

Identify the variant

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4

Save the ransom note and a sample encrypted file

2 min

Copy the ransom note and one small encrypted file (under 1 MB) to a USB stick, or photograph the note with your phone. You'll need both for the variant identification step.

The ransom note is usually one of:

• A .txt file in every encrypted folder (typically HOW_TO_DECRYPT.txt, README.txt, or _readme.txt)
• An .html file with the same purpose
• A changed desktop wallpaper - photograph it
• A lock-screen interrupt that runs at startup - rarer

Important

Don't delete the note. Variant identification depends on its exact wording, the contact email, and the bitcoin wallet address. The note is also evidence if you report to authorities.

5

Identify the variant with ID Ransomware

Tool: ID Ransomware3 min

From a clean device (your phone is fine, or another PC that wasn't on the affected network), visit id-ransomware.malwarehunterteam.com. Upload the ransom note and the sample encrypted file. The site identifies the variant family and tells you whether a free decryptor exists.

Pro tip

ID Ransomware is run by the Malware Hunter Team. Files you upload are kept private - they're used for analysis, not published. If you're concerned about uploading data anyway, you can paste the contact email and bitcoin wallet from the note - those are often enough for identification.

Phase 3~ 30-45 min

Remove the ransomware

---

The ransomware itself must be removed before any file recovery. If it's still active, anything you restore in Phase 4 gets re-encrypted within minutes.

6

Boot to Safe Mode with Networking and download the scanners

5 min

Safe Mode loads only the minimal Windows drivers, which prevents most ransomware from auto-running while you set up the scanners.

Windows 11: open Settings → System → Recovery, click Restart now next to Advanced startup. After the restart, click Troubleshoot → Advanced options → Startup Settings → Restart, then press 5 or F5.

Windows 10: click the Windows logo, hold Shift, click the Power icon and choose Restart. From the Choose-an-option screen, click Troubleshoot → Advanced options → Startup Settings → Restart, then press F5.

Once Safe Mode has loaded, turn Wi-Fi back on and download Combo Cleaner (used in step 8) and Microsoft Safety Scanner (used in step 9). Save both installers to your Desktop, then disconnect Wi-Fi again before scanning.

7

Run Microsoft Defender Offline

Tool: Built into Windows15 min

Reboot to normal Windows. Open Windows Security → Virus & threat protection → Scan options. Select Microsoft Defender Antivirus (offline scan) and click Scan now. The PC restarts into a stripped-down environment and scans the disk before Windows fully loads.

Why this comes first

Some ransomware variants drop bootkit components or kernel hooks that hide from any scanner running on the same Windows session that's already infected. A pre-boot offline scan sees the disk before the malware can load itself.

Recommended antivirus

Combo Cleaner

VB100 certified. Includes anti-trojan, registry/persistence scanning, and anti-spyware in one pass. The 7-day free trial is available.

Download Combo Cleaner

8

Run a full Combo Cleaner scan

Tool: Combo Cleaner20-40 min

Run the installer you downloaded in step 6 and start a full system scan (not the quick scan). Let it complete, review what it detected, and apply the recommended actions. Combo Cleaner quarantines the ransomware executable and the registry / scheduled-task entries that re-launch it on reboot.

9

Run Microsoft Safety Scanner and re-enable Defender

Tool: MSERT15 min

Run Microsoft Safety Scanner (MSERT.exe) as a second-opinion full scan. The binary expires every 10 days so the copy you downloaded has the latest signatures.

Once it finishes, open Windows Security → Virus & threat protection → Manage settings and confirm Real-time protection, Cloud-delivered protection, and Tamper Protection are all on. Many ransomware variants disable Defender during the attack - this is where you switch it back on so the next attempt can't repeat the trick.

Why a second scan

Different scanning engines catch different threats. Running an additional Microsoft scan after Combo Cleaner is the most underused verification step in malware removal - and free.

Phase 4~ 30-60 min · results vary

Try to recover files

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Try the steps in order. The first decryptor that works ends the recovery process - no need to do all four.

10

Check the No More Ransom Project for a free decryptor

Tool: nomoreransom.org★ Cleanest path if listed5 min

Visit nomoreransom.org and search the Decryption Tools list for the variant name returned by ID Ransomware. The project is run by Europol, the Dutch Police, and security vendors - everything listed is legitimate and free.

If a decryptor exists, download it onto a clean PC, copy it across, and follow its instructions exactly. Decryptors usually want you to point them at a sample encrypted file plus its known unencrypted version (sometimes any image you previously had a backup of works).

Free decryptors exist for parts of the STOP/Djvu, GandCrab, REvil, Avaddon, Conti and Hive families, among others. Most modern variants don't have public decryptors - if yours isn't listed, that's expected; move to the next step.

11

Try Windows Volume Shadow Copies

Tool: Shadow Explorer / vssadmin15 min

Windows automatically creates Volume Shadow Copies of files when System Restore points are made or scheduled backups run. Most ransomware tries to wipe these (vssadmin delete shadows /all /quiet), but the deletion sometimes fails partially - especially if the running user doesn't have full admin rights. When it does fail, snapshots survive that contain pre-encryption versions of your files.

First, check what's there. Open Command Prompt as Administrator and run:

vssadmin list shadows

If you see entries listed, shadow copies survived. To restore from them:

• Built-in: right-click any folder → Properties → Previous Versions tab. Pick a snapshot dated before the infection and restore.
• Better tool for browsing: install Shadow Explorer (free). It shows all snapshots as a normal file tree and lets you copy out only the files you want.

Why check this even when there's a decryptor

Shadow Copies recover the original files exactly, with no risk of decryption errors. If they survived, this is faster and cleaner than running a decryptor on the encrypted set.

12

Restore from cloud or external backup

Tool: your backup software30 min

If you have a backup that pre-dates the infection, this is the cleanest recovery available. Important precautions:

• Don't reconnect a backup drive until Phase 3 is complete. If the ransomware is still active, plugging in the backup encrypts it too.
• For cloud backups (OneDrive, Dropbox, Google Drive, iCloud), use the Version History feature to roll individual files back to pre-encryption versions.
• OneDrive specifically has a "Restore your OneDrive" feature: if it detected mass file changes, you can roll back the entire account up to 30 days. Sign in at OneDrive on the web, click the Settings gear, and choose Restore your OneDrive. Microsoft 365 subscribers also get ransomware detection alerts; non-subscribers get one free recovery.
• Verify the restored files open correctly before you delete the encrypted set. Test a few documents, photos, and any database / project files.

13

Try Recuva as a last-resort recovery

Tool: Recuva30 min

Recuva is a long shot, not a primary recovery tool. Most modern ransomware encrypts files in place - it reads the original, encrypts the data, and writes the encrypted bytes back to the same disk location. In that case, the original isn't deleted, just rewritten - and Recuva has nothing to find.

But for older or simpler variants that deleted originals before creating encrypted copies (rather than encrypting in place), Recuva can sometimes pull the originals from unallocated disk space. Worth trying as a last resort, especially before you use the disk much further.

If you try it:

• Stop using the disk as much as possible - every disk write reduces recovery odds
• Run Recuva from a USB stick, not from the affected disk
• Use Deep Scan mode (slower but the only mode worth running for this scenario)

Don't skip the steps above expecting Recuva to bail you out. It works in maybe 5-20% of cases, depending on the variant and how soon you try.

Phase 5~ 20 min + ongoing

Report & prevent re-infection

---

14

Report the attack to authorities

10-20 min

Even if your files aren't recovered, your report helps authorities track variants, attribute groups, and warn future victims. In some jurisdictions (especially the US and UK) early reporting can sometimes help recall a wired ransom payment via banking partners.

United States: ic3.gov (FBI) + stopransomware.gov (CISA)

United Kingdom: reportfraud.police.uk (Report Fraud, the successor to Action Fraud) + NCSC

Canada: antifraudcentre.ca

Australia: ReportCyber

Spain: Policía Nacional (Oficina Virtual de Denuncias)

France: cybermalveillance.gouv.fr

Germany: BKA

Italy: Polizia Postale

Netherlands: Politie

Poland: CERT Polska

Portugal: CNCS

EU (other): your national CERT

Save the report number - banks, insurers, and credit bureaus will ask for it. If you operate a business, you may also have legal disclosure obligations (GDPR in the EU, state breach laws in the US) that run on a 72-hour clock.

15

Plan 3-2-1 backups going forward

30 min initial

The single best defense against ransomware is a tested backup. Use the 3-2-1 rule:

• 3 copies of your data
• 2 different storage media (e.g., internal drive + external drive)
• 1 offline / air-gapped copy (an external drive that isn't always connected)

Recommended cadence:

• Daily: cloud sync (OneDrive, Dropbox, Google Drive) - convenient, but vulnerable if the ransomware reaches the sync folder. The Version History feature is what saves you
• Weekly: external drive that you connect briefly, then disconnect - the air-gap is what protects against ransomware
• Monthly: a second external drive stored off-site (different physical location) - protects against fire, theft, flood

Important

Test the backup at least once. Open a few files from it, check sizes match, restore one to a different folder. An untested backup isn't a backup - it's a hope.

16

Patch the entry point and monitor for 30 days

5 min/day · 30 days

Most reinfections happen via the same vector that worked the first time. Until you've patched the entry point, watch for:

• Unusual disk activity, unexpected file modifications, or unfamiliar processes in Task Manager
• Unexpected reboots or new accounts you didn't create
• Defender or your antivirus turning itself off again

Common entry vectors and what to do about each:

• Phishing email with a malicious attachment - review email filters and train yourself / staff to recognise the patterns - see pcrisk's Phishing/Scam reference
• Exposed RDP with weak passwords - disable Remote Desktop from Settings → System → Remote Desktop if you don't need it. If you do, put it behind a VPN and require a long password plus MFA
• Unpatched VPN appliances or public-facing apps - check the vendor's advisories page and apply the latest firmware
• Cracked / pirated software - was the most common vector for STOP/Djvu in particular. Don't run software from torrent sites

Run a Combo Cleaner scan weekly for the first month. Update Windows, browsers, and applications aggressively.

Important: Removing a ransomware infection requires a full system scan, not a manual file delete. If you're not confident with the manual procedure, run an automated scan with Combo Cleaner and Windows Defender and stop there - that combination removes the vast majority of consumer ransomware variants. Then move to Phase 4 for file recovery, or to Phase 5 if your files are unrecoverable and you need to start fresh from a clean Windows install.

Frequently Asked Questions (FAQ)

How was my computer hacked and how did hackers encrypt my files?

Threat actors use different ways to trick users into executing ransomware. In most cases, they send emails containing malicious attachments/links or use fake installers for cracked/pirated software. They also use untrustworthy sources for downloading software, fake updaters, and Trojans to deliver ransomware.

How to open ".RYK" files?

It is impossible to open/use these files - they are encrypted and have to be decrypted so they can be opened.

Where should I look for free decryption tools for RYK ransomware?

In case of a ransomware attack you should check the No More Ransom project website (more information above).

I can pay you a lot of money, can you decrypt files for me?

We do not provide a decryption service. Third parties claiming that they can decrypt files and ask for money in return are scammers or act as a man-in-the-middle. As a rule, it is not possible to decrypt files without tools purchased from the attackers unless ransomware is flawed.

Will Combo Cleaner help me remove RYK ransomware?

Combo Cleaner will run a system scan and eliminate detected ransomware. Note that security software cannot decrypt the encrypted files. It removes ransomware to prevent more damage.