How to remove CrySome from infected devices

What kind of malware is CrySome?

CrySome is a remote access Trojan (RAT) that lets cybercriminals take control of an infected device. This RAT can steal files and passwords, spy on activity, and run commands remotely. What makes CrySome even more serious threat is that it can hide itself, disable antivirus software, and stay on the system even after resets or removal attempts.

More about CrySome

Once CrySome connects to its server, it sends information about the infected device. Transmitted details include the computer's username, operating system version, time since boot, and country/region. It also sends the title of the window the user is currently using (without enabling remote session).

Then, the RAT sets up an infected system to receive commands. Some basic features are always active, while others can be turned on or off depending on settings. CrySome supports a wide range of commands, allowing cybercriminals to engage in various malicious activities.

It can run shell/PowerShell commands, download and run files, upload and download files, browse, read, and delete files, take screenshots, force the system to reboot, list or kill running programs, take pictures with the webcam, and access (and use) the microphone. CrySome can also enable direct messaging between cybercriminals and victims.

Furthermore, the RAT can create SOCKS/reverse proxy tunnels for hidden network access, view screens, control mouse and keyboard, manage multiple monitors, secretly control a hidden user session, and run apps invisibly, steal saved browser passwords and cookies, and record everything typed with a keyboard.

Persistence and defense evasion

CrySome creates a scheduled task to relaunch itself every few minutes and plants itself as a Windows service that starts at boot and restarts if it crashes. It copies itself into hidden backup folders so it can recover if deleted and adds registry entries so it runs automatically when Windows starts. The RAT can modify certain system files to remain even after factory resets.

Furthermore, CrySome hides its files and locks them so they cannot be deleted, and runs a "watcher" process that restarts it if stopped. It can mark itself as a critical system process and block security tools from accessing or stopping it.

Additionally, the RAT finds and kills antivirus processes, blocks antivirus installation files, stops antivirus services and prevents them from restarting, and disables Microsoft Defender features (such as real-time protection, cloud protection, scanning, etc.). It can also block security programs from launching at all.

Conclusion

CrySome gives attackers control over an infected device and allows them to steal data, spy on users, and perform many malicious actions remotely. It is designed to stay hidden and keep running by using strong persistence methods that make it hard to remove, even after restarts or system resets. Thesce capabilities make it a dangerous threat.

More examples of RATs are GHOSTFORM, KarstoRAT, and Moonrise.

How did CrySome infiltrate my computer?

Malicious software such as CrySome is commonly delivered via infected files, including executables, compressed files, scripts, and documents such as PDFs and Office files. Simply opening these files or taking additional steps can trigger an infection.

Cybercriminals use various distribution methods to spread malware, including email attachments or links, fake software downloads, security vulnerabilities, fraudulent tech support messages, malicious or hacked websites, pirated or cracked software, deceptive ads, infected removable drives, peer-to-peer sharing platforms, and third-party downloaders.

How to avoid installation of malware?

Only open links or attachments from trusted sources, and be cautious with unexpected emails or messages, especially if they come from unknown senders. Make sure to download apps and software only from official websites or verified app stores, and avoid using cracked programs, pirated software, or key generators.

Keep your operating system and all applications up to date, and avoid interacting with ads, pop-ups, or other content on untrusted websites. Additionally, to avoid agreeing to get notifications from shady pages.

If you believe that your computer is already infected, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.

Website promoting CrySome (source: cyfirma.com):

Crysome's admin panel (source: cyfirma.com):

Update July 14, 2026 - Researchers at LevelBlue have documented a CrySome RAT campaign targeting workers in the freight and logistics industry. Attackers send spear-phishing emails impersonating trucking companies, directing recipients to a convincing fake freight rate confirmation website (signindat[.]com) that delivers the malware disguised as a document download.

After the download, a realistic-looking freight rate PDF is displayed to prevent suspicion. The attack unfolds in multiple stages using batch scripts, PowerShell, and loader programs before the RAT is deployed. CrySome specifically targets saved passwords and cookies from Chromium-based browsers, including Chrome, Microsoft Edge, and Brave. (source: levelblue.com).

Screenshot of the fake freight rate confirmation website (signindat[.]com):

How to remove malware manually?

Most trojan infections can be removed by running a full system scan with Combo Cleaner. The full manual procedure below is for cases where automatic removal failed, where you want to verify a scan caught everything, or where the threat has multiple persistence points.

Tools you'll need

Combo Cleaner Antivirus 7-days free trial

Recommended primary scanner. VB100 certified. The 7-day free trial is available.

Microsoft Defender Offline Free · built-in

Built into Windows. Boots to a clean environment to catch rootkits.

Process Explorer Free

From Microsoft Sysinternals. Better than Task Manager - shows full paths and signatures.

Autoruns Free

From Microsoft Sysinternals. Lists every place malware can persist on your system.

Microsoft Safety Scanner (MSERT) Free

Official Microsoft on-demand scanner. Always-current signatures - expires every 10 days.

Phase 1~ 5 min

Contain - limit the damage

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1

Disconnect from the network

30 secNo tool needed

Unplug your Ethernet cable and turn off Wi-Fi. If you're on a laptop, the airplane-mode key works fastest.

Why this matters

Many trojans exfiltrate data - saved browser passwords, banking sessions, screenshots - and accept remote commands. Cutting the network stops both immediately. Keep it disconnected until Phase 4.

2

Boot into Safe Mode with Networking

3 min

Safe Mode loads a minimal set of drivers and stops most malware from auto-running. "With Networking" lets you download tools - re-enable Wi-Fi only after you've booted in.

Windows 11

Open Settings → System → Recovery. Click Restart now next to Advanced startup.

Your computer will restart into the "Choose an option" menu. Click Troubleshoot → Advanced options → Startup Settings → Restart. After the second reboot, press 5 or F5.

Windows 10

Click the Windows logo, hold Shift, click the Power icon and choose Restart. In the Choose an option screen, click Troubleshoot → Advanced options → Startup Settings → Restart. Press F5.

Windows 8

Go to the Start Screen, type Advanced, select Settings → Advanced startup options → Restart now → Troubleshoot → Advanced options → Startup settings → Restart → F5.

Note: Windows 8 reached end-of-life in January 2023 - running on it puts you at much higher risk of reinfection.

Windows 7

Click Start → Shut Down → Restart → OK. As the system boots, press F8 repeatedly until the Windows Advanced Options menu appears, then choose Safe Mode with Networking.

Note: Windows 7 reached end-of-life in January 2020 - running on it puts you at much higher risk of reinfection.

Phase 2~ 15 min

Identify - find what's hiding

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3

Inspect running processes with Process Explorer

Tool: Process Explorer5 min

Download Process Explorer from Microsoft Sysinternals. Run it as Administrator. Click Options → Verify Image Signatures and View → Lower Pane View → DLLs.

Sort by "Verified Signer." Anything unsigned running from %AppData%, %LocalAppData%, %Temp%, or %ProgramData% is suspicious. Right-click → Properties to see the full image path. Right-click → "Search Online" to look up unfamiliar process names.

Why not just Task Manager

Task Manager hides full file paths, doesn't show digital signatures, and groups processes in ways that make malware easy to miss. Process Explorer is the same tool Microsoft engineers use.

4

Map every persistence point with Autoruns

Tool: Autoruns 14.x10 min

Download Autoruns. Right-click Autoruns.exe and choose Run as administrator - without elevation, Autoruns can't inspect protected registry hives.

In the menu, open Options → Hide Microsoft Entries and Options → Hide Empty Locations, then click Refresh.

Modern trojans don't just live in startup. Walk through these tabs and look for unsigned or unfamiliar entries:

• Logon - classic Run/RunOnce keys
• Scheduled Tasks - frequent hiding spot, especially tasks with PowerShell, MSHTA, or rundll32 actions
• Services - unsigned services in non-Microsoft folders
• WMI - Event Subscriptions are a stealthy persistence mechanism (MITRE T1546.003)
• Image Hijacks - Image File Execution Options "Debugger" abuse
• AppInit - DLLs loaded into every GUI process
• Browser plug-ins - unsigned add-ons across all installed browsers

Pro tip

Right-click any suspicious entry → "Jump to Image" to see the actual file. Right-click → "Search Online" opens VirusTotal for the file hash. Don't delete yet - just write down the file paths and entry names. We'll remove them after the scans.

5

Check the hosts file and DNS settings

3 minBuilt into Windows

Trojans often redirect bank, antivirus, and update domains to attacker-controlled servers by editing the hosts file or DNS settings.

Hosts file: Open Notepad as Administrator and open C:\Windows\System32\drivers\etc\hosts. Legitimate entries are commented with #. Any uncommented IP-to-domain mapping is suspicious - especially redirects for microsoft.com, windowsupdate, or your bank.

DNS settings: Open Command Prompt as Administrator and run ipconfig /all. Confirm your DNS servers point to your ISP, your router, or a known public resolver (Cloudflare 1.1.1.1, Google 8.8.8.8). Then open Settings → Network & internet → [your adapter] → DNS server assignment and verify both DNS and DNS over HTTPS (DoH) settings haven't been hijacked.

Why this matters

A clean PC with hijacked DNS is still a compromised PC. You'll think you're at chase.com and you'll be at the attacker's clone.

Phase 3~ 60-90 min

Remove - three scans, one cleanup

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No single antivirus catches everything. The order below is intentional: offline scan first (catches rootkits before Windows fully loads), then on-demand scanners on the running system, then manual cleanup of anything they missed.

6

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. Your computer will restart into a stripped-down environment and scan before the full operating system loads.

Why this comes first

Rootkits and bootkits 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 hide itself.

Recommended antivirus

Combo Cleaner

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

Download Combo Cleaner

7

Run Combo Cleaner full system scan

Tool: Combo Cleaner20-40 min

Install Combo Cleaner and run a full system scan (not the quick scan). Let it complete fully, review the detected threats, and apply the recommended actions. Combo Cleaner will quarantine known trojans and registry persistence.

8

Run Microsoft Safety Scanner as a second-opinion scan

Tool: Microsoft Safety Scanner15 min

Download Microsoft Safety Scanner (MSERT.exe), Microsoft's free on-demand tool. The binary expires every 10 days, which means every download has the latest signatures. Run a full scan after Combo Cleaner to catch anything one engine alone might miss.

Why a second scan

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

9

Manually remove anything still listed in Autoruns

Tool: Autoruns10 min

Reopen Autoruns. Anything you flagged in Step 4 that's still present hasn't been caught by the automated scans. For each remaining suspicious entry: right-click → Delete in Autoruns (this removes the persistence registration), then navigate to the file path and delete the actual file. Empty the Recycle Bin.

Important

Some malware files reappear after deletion because something else on the system recreates them. If you delete a file and it returns within minutes, you have a remaining persistence point that Autoruns didn't show - usually a service or scheduled task running under SYSTEM. Re-run the scans from Steps 6-8 or proceed to a clean install (see end of guide).

Phase 4~ 15 min

Recover - restore browsers and security

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10

Reset browsers and clear notification permissions

5 min

Trojans and adware frequently hijack browsers - change the default search engine, install rogue extensions, or grant themselves notification permissions to keep displaying scam pop-ups even after the malware is gone.

• Chrome: visit chrome://settings/reset and click "Restore settings to their original defaults." Then visit chrome://settings/content/notifications and remove any unfamiliar sites.
• Edge: visit edge://settings/reset. Then check edge://settings/content/notifications.
• Firefox: open about:support and click Refresh Firefox (Firefox uses "Refresh," not "Reset"). Then check Settings → Privacy & Security → Permissions → Notifications.

Review installed extensions in each browser and remove anything you don't recognize, especially extensions you didn't install yourself.

11

Re-enable Defender, Tamper Protection, and update everything

10 min

Many trojans disable security software. Open Windows Security → Virus & threat protection → Manage settings and confirm Real-time protection, Cloud-delivered protection, and Tamper Protection are all turned on. Tamper Protection prevents malware from disabling Defender silently.

Then run Windows Update (Settings → Windows Update → Check for updates) and update your browsers and applications. The infection vector that let the trojan in originally usually involves outdated software.

Phase 5~ 15 min + 7 days

Verify & secure

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12

Change passwords from a clean device

20 min⚠ Critical

If the trojan was an info-stealer (Lumma, RedLine, Vidar, and similar are extremely common), assume every password saved in your browser is compromised. Change them from a different, known-clean device - your phone is fine if it's not infected.

Recommended order:

1. Primary email first - it's the recovery hub for everything else
2. Banking and financial accounts
3. Password manager master password (if you use one)
4. Social media, shopping, and remaining accounts

Where available, enable phishing-resistant multi-factor authentication (passkeys / FIDO2 hardware keys / authenticator apps) - SMS-based MFA is bypassable by sophisticated attackers.

13

Verify the clean and monitor for 7 days

5 min + 1 week monitoring

Reconnect to the network and run one final full scan with Combo Cleaner. Open Task Manager (Ctrl + Shift + Esc) and switch to the Startup apps tab - confirm nothing suspicious has reappeared.

Over the next 7 days, watch for symptom recurrence: unexpected high CPU usage, unknown processes returning, browser redirects, or pop-ups. If anything returns, you missed a persistence point and the procedure needs to be repeated - or you may have a deeper compromise that requires a clean install.

When to clean install Windows instead

Manual removal isn't always the right answer. Reinstalling Windows from scratch is the only way to be 100% certain when:

• The malware reappears after every removal attempt
• A bootkit or UEFI rootkit was detected (this class of threat sits below the operating system and survives a normal Windows reinstall)
• A confirmed credential-theft trojan ran with administrator privileges (Lumma, RedLine, Vidar) - the system likely has multiple unknown payloads
• The PC is used for online banking, business email, or anything where partial doubt isn't acceptable

A clean install is a 30-60 minute process: Windows 11 reinstall via Settings → System → Recovery → Reset this PC → Remove everything → Cloud download. Back up documents to external storage first, scan the backup with Combo Cleaner before restoring it, and reinstall applications fresh - never restore them from a backup of the infected system.

Important: Manual removal requires advanced computer skills. If you're not confident identifying system files from malicious files, run an automated scan with Combo Cleaner and Windows Defender and stop there - that path catches the vast majority of consumer trojans without the risk of breaking Windows by deleting the wrong file.

Frequently Asked Questions (FAQ)

My computer is infected with CrySome malware, should I format my storage device to get rid of it?

While a full reset can remove CrySome, it will wipe all files from the system. In most cases, using a reputable security program such as Combo Cleaner should be tried first.

What are the biggest issues that malware can cause?

Malware can corrupt or delete files, inject additional malware, spy on victims, and more. This can lead to severe outcomes such as financial damage, data and identity theft, unauthorized account access, data loss, and other serious problems.

What is the purpose of CrySome RAT?

CrySome RAT is designed to secretly spy on users by accessing the screen, webcam, microphone, and system activity. It can also steal sensitive data like passwords, files, cookies, and system information. At the same time, it gives attackers full remote control of the device while staying hidden and disabling security tools.

How did a malware infiltrate my computer?

Malware is commonly delivered through malicious executables, archives, scripts, and documents, which can infect a device when opened or run. Cybercriminals use malicious websites, phishing emails with attachments or links, fake tech support scams, software flaws, cracked programs, harmful online ads, infected USB drives, peer-to-peer sharing networks, and untrusted third-party download sources to deliver malware.

Will Combo Cleaner protect me from malware?

Yes, Combo Cleaner is capable of finding and removing most known malware infections. However, some advanced threats can be deeply hidden in the system, so running a complete system scan is important to ensure full detection.