Security researchers have recently discovered a new form of trollware called Cancer Trollware, which disguises itself as a fake browser update for Google Chrome, Mozilla Firefox, and Internet Explorer. Packed as cancer.exe, this program is designed to disrupt users’ experiences by altering file icons, restricting access to files, resizing program windows, and displaying annoying pop-ups.
Although Cancer Trollware does not cause direct damage like ransomware or spyware, it significantly affects usability by interfering with everyday tasks. Users have reported flashing windows, disabled file access, and an incessant melody playing in the background. Furthermore, the program gains boot persistence by modifying the Windows Registry, making it difficult to remove.
Summary of Cancer Trollware
Category | Details |
---|---|
Threat Type | Trollware (Crapware) |
File Name | cancer.exe |
Detection Names | Varies by anti-malware software (Trollware.Cancer, Crapware.Cancer) |
Symptoms | – File icons change – Restricted file access with error messages – Windows flash, move, resize, or minimize randomly – Annoying melody plays in the background – Pop-ups with a mischievous child’s face appear |
Damage | No permanent damage, but highly disruptive to workflow, gaming, and productivity |
Distribution Methods | Fake browser update for Chrome, Firefox, and Internet Explorer |
Danger Level | Medium (not destructive, but highly annoying and persistent) |

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How Cancer Trollware Operates
Cancer Trollware presents itself as a legitimate browser update, often tricking users with familiar security icons. Upon execution, the program triggers a User Account Control (UAC) prompt, gaining administrative privileges. Once active, it wreaks havoc on the user’s system by:
- Changing default file icons, making them unrecognizable
- Preventing users from opening files by displaying an error message
- Resizing, minimizing, and moving program windows randomly
- Playing a repetitive and frustrating melody
- Displaying pop-ups with a grinning child’s face
- Running persistently, even in Safe Mode
One of the most frustrating aspects of Cancer Trollware is its ability to interfere with gaming sessions, work-related tasks, and overall productivity. While it may not be categorized as severe malware, it is extremely difficult to remove and requires the assistance of experienced technicians or anti-malware utilities.
How to Remove Cancer Trollware (Cancer.exe) from Your PC
If your system is infected with Cancer Trollware, you may be experiencing constant disruptions, including flashing windows, disabled file access, and annoying pop-ups. While this trollware is not directly harmful, it is persistent and difficult to remove due to boot persistence via Registry modifications. Follow this step-by-step removal guide to completely eliminate Cancer.exe from your system.
Step 1: Boot Into Safe Mode
Since Cancer Trollware can interfere with normal system operations, you should boot into Safe Mode with Networking to perform the removal.
For Windows 10 & 11
- Press Win + R, type
msconfig
, and hit Enter. - Go to the Boot tab.
- Check Safe boot and select Network.
- Click Apply, then OK.
- Restart your PC.
Alternatively, you can:
- Hold Shift while clicking Restart from the Start menu.
- Navigate to Troubleshoot > Advanced options > Startup Settings > Restart.
- Press 4 or 5 to enter Safe Mode with Networking.
Step 2: Terminate Cancer.exe Using Task Manager
Once in Safe Mode, you need to stop Cancer Trollware from running in the background.
- Press Ctrl + Shift + Esc to open Task Manager.
- Look for cancer.exe or any suspicious process using excessive CPU or memory.
- Right-click it and select End Task.
If the task restarts automatically, proceed to the next step.
Step 3: Uninstall Suspicious Programs
Cancer Trollware may be listed as an installed program.
- Press Win + R, type
appwiz.cpl
, and hit Enter. - Look for any unknown, suspicious, or recently installed programs.
- Select them and click Uninstall.
Step 4: Remove Cancer Trollware from Startup
Prevent the malware from launching at boot.
- Open Task Manager (Ctrl + Shift + Esc) and go to the Startup tab.
- Look for cancer.exe or any suspicious entry.
- Right-click and select Disable.
Step 5: Delete Cancer Trollware Files
- Open File Explorer (
Win + E
). - Navigate to:
C:\Users\YourUsername\AppData\Roaming\
C:\Users\YourUsername\AppData\Local\
C:\ProgramData\
C:\Windows\Temp\
- Delete any cancer.exe file or unknown folders.
Use the search bar in File Explorer and type cancer.exe
, then delete all results.
Step 6: Remove Cancer Trollware from the Windows Registry
⚠ Warning: Editing the Registry incorrectly can cause system issues. Proceed with caution.
- Press Win + R, type
regedit
, and hit Enter. - Navigate to:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- Look for cancer.exe or any unknown entry.
- Right-click and Delete the suspicious keys.
Step 7: Scan Your PC with a Reputable Anti-Malware Tool
To ensure complete removal, scan your system using a trusted anti-malware program such as SpyHunter.
- Download and install the software.
- Perform a Full Scan.
- Remove any detected threats.
Step 8: Restore File Icons & Fix System Settings
Cancer Trollware alters file icons and may prevent file access.
Restore Default Icons
- Right-click the Desktop and select Personalization.
- Go to Themes > Desktop Icon Settings.
- Click Restore Default and Apply changes.
Enable File Access (If Blocked)
- Press Win + R, type
gpedit.msc
, and hit Enter. - Navigate to:
- User Configuration > Administrative Templates > System.
- Find “Don’t run specified Windows applications” and set it to Not Configured.
Step 9: Reset Web Browsers (Optional but Recommended)
Since Cancer Trollware spreads via fake browser updates, reset your browsers.
Google Chrome
- Open Chrome and go to Settings > Reset settings.
- Click Restore settings to their original defaults > Reset settings.
Mozilla Firefox
- Type
about:support
in the address bar and hit Enter. - Click Refresh Firefox.
Microsoft Edge
- Go to Settings > Reset settings.
- Click Restore settings to their default values > Reset.
Step 10: Restart Your Computer & Monitor for Issues
Once all steps are completed, restart your PC normally and check if:
✅ Files are accessible
✅ Icons are restored
✅ Pop-ups and flashing windows are gone
Conclusion
Cancer Trollware may not steal data or encrypt files like more dangerous malware types, but its disruptive nature can make any user’s computing experience unbearable. Avoid downloading browser updates from unofficial sources and always verify the legitimacy of software before installation. If your system is affected, removal may require professional assistance, as this trollware ensures persistence by modifying system settings.

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