How to remove TamperedChef stealer from your operating system

What kind of malware is TamperedChef?

TamperedChef is the name of a malicious program classified as a stealer. As the classification implies, this software exfiltrates vulnerable information from infected systems. This malware has been around since at least May 2025.

In recent campaigns that took place during the summer of the same year, the stealer was infiltrated into systems by Potentially Unwanted Applications (PUAs). These apps acted as sleeper agents that were activated on the 21st of August 2025 and then downloaded/installed the TamperedChef stealer.

TamperedChef malware overview

In the campaigns spreading TamperedChef that were observed in the summer of 2025, the infection began with PUAs masquerading as genuine software like PDF editors, browsers, or manual finders (potentially other disguises). Only one app could be the originator of TamperedChef's infection, but in some instances, they infiltrated systems in a bundle or installed one another before the stealer was introduced.

The application(s) remained harmless software, yet constantly checked for available updates. On the 21st of August, an update was received, and an executable file was downloaded/installed, which caused the TamperedChef stealer infection. These unwanted apps may also turn infected machines into residential proxies.

TamperedChef malware is designed to steal sensitive data from devices. It begins by collecting relevant device data, including lists of installed security products and browsers. From browsers, TamperedChef can extract Internet cookies and saved log-in credentials (usernames/passwords). This program can terminate browsers that are running, likely for the purpose of accessing information that would otherwise be inaccessible.

It must be mentioned that malware developers often improve upon their software and methodologies. It is likewise noteworthy that stealers can often extract data (e.g., log-in credentials, personally identifiable details, finance-related information, etc.) from various apps, such as browsers, email clients, FTP (File Transfer Protocol) clients, messengers, VPN (Virtual Private Network) clients, gaming-related software, password managers, cryptocurrency wallets, and so on. Therefore, potential future versions of TamperedChef could have a broader target list or additional/different capabilities.

To summarize, the presence of malicious software like the TamperedChef stealer on devices can lead to severe privacy issues, financial losses, and identity theft.

Stealer-type malware examples

We have written about numerous malicious programs; Raven, DarkCloud, RMC stealer, and Leet are merely a few of our latest articles on stealers.

Data-stealing malware can target a wide variety of information or specific details only. Yet regardless of what (if any) data that a piece of malicious software targets – its presence on a system endangers device integrity and user safety. Therefore, all threats must be eliminated immediately upon detection.

How did TamperedChef infiltrate my computer?

TamperedChef has been distributed through multiple useful-sounding applications in campaigns that began in the summer of 2025. The stealer itself has been around since at least the 15th of May, and one of the first identified operations started on the 16th of June. The apps remained dormant for weeks or months until being activated to download an update, resulting in the TamperedChef infection on the 21st of August.

As of the time of writing, five campaigns have been identified, and all relied on abusing Google Ads to push deceptive promotional pages (malvertising). There is an interesting correlation between the length of an advertising campaign purchased on Google and the time the sleeper apps' malicious abilities were activated. Over 50 websites were linked to these operations.

Some of the applications may be flagged by security vendors as PUAs (Potentially Unwanted Applications), yet upon activation – cause high-risk malware (TamperedChef) infections. App disguises include a tool for finding manuals – "ManualFinder", browsers – "OneStart" and "EpiStart" ("EpiBrowser"), and PDF document editing software – "PDF Editor By AppSuite" ("AppSuite PDF Editor", "AppSuite-PDF"), "PDF Editor", and "Fast PDF Pro".

The applications had certificates issued by four different companies; while the source might have been legitimate, there is evidence suggesting that at least some of the issuing entities are fraudulent.

As previously mentioned, TamperedChef infection may originate from a single app, a bundle, or following an installation chain. To expand upon this: "PDF Editor By AppSuite" usually downloads "PDF Editor", "OneStart" may download "PDF Editor By AppSuiter", and "OneStart" and "PDF Editor" both may download "Manual Finder".

It must be mentioned that TamperedChef could be introduced into systems by other applications or a different method altogether. Generally, malware proliferation relies on phishing and social engineering.

Aside from malvertising, malware is commonly distributed via trojans (backdoors/loaders), drive-by (stealthy/deceptive) downloads, online scams, malicious attachments or links in spam emails/messages, dubious download channels (e.g., freeware and third-party websites, Peer-to-Peer sharing networks, etc.), fake updates, pirated programs/media, and illegal software activation tools ("cracks").

Furthermore, some malicious programs can self-spread through local networks and removable storage devices (e.g., external hard drives, USB flash drives, etc.).

Malware is typically disguised as or bundled with ordinary software/media files. Infectious files come in various formats, e.g., executables (EXE, RUN, etc.), archives (RAR, ZIP, etc.), documents (PDF, Microsoft Office, Microsoft OneNote, etc.), JavaScript, and so on. Merely opening a malicious file can be enough to trigger the infection process.

How to avoid installation of malware?

We highly recommend researching software and downloading it only from official/verified sources. All programs must be activated and updated using functions/tools provided by genuine developers, as those acquired from third-parties can contain malware.

Another recommendation is to be vigilant when browsing since the Internet is full of deceptive and dangerous content. Incoming communications (e.g., emails, DMs/PMs, SMSes, etc.) must be approached with caution. Attachments or links found in suspect/irrelevant mail must not be opened, as they can be virulent.

It is paramount for device/user safety to have a dependable antivirus installed and kept updated. Security software must be used to run regular system scans and to remove potential and active threats. 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.

TamperedChef stealer spreading PUA (PDF Editor By AppSuite):

TamperedChef stealer spreading PUA (OneStart):

TamperedChef stealer spreading PUA (EpiStart [EpiBrowser]):

Update April 8, 2026: In some cases, the malware uses a multi-stage approach where the installed app appears harmless at first, then activates the infostealer payload, helping it evade early detection and increase infection success.

The execution chain involves a fake installer that drops several components, including a main executable, a JavaScript-based loader, and additional binaries that communicate with command-and-control infrastructure, while also establishing persistence via scheduled tasks and registry keys.

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 TamperedChef malware, should I format my storage device to get rid of it?

Malware removal rarely requires such drastic measures.

What are the biggest issues that TamperedChef malware can cause?

The dangers posed by an infection depend on the malware's capabilities and the cyber criminals' modus operandi. TamperedChef is designed to steal sensitive information from devices (like browser cookies and log-in credentials). Generally, infections of this kind can result in serious privacy issues, financial losses, and identity theft.

What is the purpose of TamperedChef malware?

Malware is predominantly used for profit. However, attackers may also use malicious programs to amuse themselves, realize personal grudges, disrupt processes (e.g., websites, services, companies, etc.), engage in hacktivism, and launch politically/geopolitically motivated attacks.

How did TamperedChef malware infiltrate my computer?

TamperedChef has been distributed through several PUAs, which masqueraded as genuine tools before being updated to operate in a malicious capacity. These applications were promoted through malignant Google Ads (malvertising). Other distribution techniques are not unlikely.

Malware is most commonly proliferated via trojans, drive-by downloads, spam mail, online scams, suspicious download sources (e.g., unofficial and free file-hosting sites, P2P sharing networks, etc.), illegal software activation tools ("cracks"), and fake updates. Some malicious programs can even self-spread through local networks and removable storage devices.

Will Combo Cleaner protect me from malware?

Combo Cleaner can detect and remove most of the known malware infections. Remember that performing a complete system scan is essential since sophisticated malicious programs tend to hide deep within systems.