Cybersecurity researchers have recently uncovered a new form of mischievous malware known as Cancer Trollware. Disguised as a fake browser update for Google Chrome, Internet Explorer, and Mozilla Firefox, this program—packed as ‘cancer.exe’—is designed to disrupt users’ experience rather than steal data or cause direct damage. While not classified as a severe security threat, Cancer Trollware can be highly frustrating to deal with due to its ability to manipulate system settings, restrict access to files, and create a chaotic user experience.
Threat Summary
Attribute | Details |
---|---|
Threat Name | Cancer Trollware |
Threat Type | Trollware (Crapware) |
Associated File | cancer.exe |
Detection Names | Varies by antivirus, potentially detected as Trollware:Win32/Cancer or PUA:Win32/Crapware |
Symptoms | Windows flashing, minimized and moved windows, file access restrictions, pop-up images of a mischievous boy, background music |
Damage | Disrupts work and gaming, difficult removal process, persistent annoyance |
Distribution Methods | Fake browser updates, phishing emails, malicious downloads |
Danger Level | Moderate (Highly annoying but not severely harmful) |

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What is Cancer Trollware?
Cancer Trollware falls under the category of Trollware or Crapware, a type of software designed to annoy users by altering system settings, disrupting normal operations, and making it difficult to regain control of the infected PC. The executable file is approximately 3 MB in size and requires administrative privileges to run, prompting a User Account Control (UAC) warning upon execution.
Once installed, Cancer Trollware modifies the system’s registry to gain boot persistence, ensuring that it continues running even after a system restart. Additionally, it can operate in Safe Mode, making its removal more complicated than conventional software.
Symptoms of Infection
Users affected by Cancer Trollware have reported a variety of disruptive symptoms, including:
- Inability to access files due to changed default icons and file restrictions.
- System warning messages, such as: “The operation has been canceled due to the restrictions in effect on this computer. Please, contact your system administrator.”
- Uncontrollable window behavior, including resizing, moving, minimizing, and flashing of program windows.
- Annoying background audio, featuring an irritating melody that continuously plays.
- Pop-ups featuring a mischievous-looking boy, appearing at random intervals.
Distribution and Infection Method
Cancer Trollware is primarily distributed through:
- Fake browser updates (e.g., Google Chrome, Mozilla Firefox, Internet Explorer).
- Malicious software downloads from untrusted sources.
- Links in phishing emails that trick users into downloading and running cancer.exe.
Damage and Consequences
Although Cancer Trollware does not appear to have data-stealing capabilities, its impact on usability is substantial.
- Work disruption: Users find it nearly impossible to work due to erratic system behavior.
- Gaming interference: The malware can disrupt gaming sessions by continuously moving or minimizing windows.
- Difficult removal: Due to boot persistence and Safe Mode execution, removal can be a lengthy and frustrating process.
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 Networkingto 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 be as dangerous as ransomware or spyware, but its persistent disruptions make it a significant nuisance. The ability to modify file access, alter window behavior, and resist easy removal means users should exercise caution when downloading software updates from unverified sources. As this program gains boot persistence and can run in Safe Mode, removing it can be challenging without professional assistance or robust anti-malware tools.

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