FBI Department of Defense virus: what it is and how to remove it

FBI Department of Defense virus is a dangerous ransomware, which is expected to replace FBI virus. This threat is extremely consistent when it comes to scaring its victims and making them pay an invented fine of $300.

Facts checked October 7, 2026. Removal steps tested on Windows 11 (26H2) and checked against Microsoft's and the browser makers' current documentation. Sections marked as our earlier report are the original text: they describe the threat as it was then and have not been reviewed since. The 2026 status, the removal steps and the questions are current.

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FBI Department of Defense virus: 1
FBI Department of Defense virus as our 2021 report showed it.

FBI Department of Defense virus: summary

Detection namesNo Microsoft detection name is known
Ransom notehelp09.html; the text is quoted in full below
ContactNot recorded in our earlier report
Encrypted file extensionNot recorded in our earlier report
DecryptorNo free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates
DistributionNot recorded in the old report
Removal

Scan the PC with security software to find and remove the malware and anything installed with it. Fortect scans Windows for malware and repairs the system files and settings it damaged.

Remove it nowTo use the full-featured product, you have to purchase a license for Fortect. The scan is free.
Show 8 more facts
DamageNot recorded in the old report
NameFBI Department of Defense virus
TypeFile-encrypting ransomware
SymptomsA ransom note left in folders
EvidenceOne write-up by a security site; details still limited
Free decryptorNo free decryptor is known (checked 7 October 2026)
First seen26 April 2021
Facts checked7 October 2026
  • Note file: help09.html

From our report of Apr 2021 · not reviewed since

What FBI Department of Defense virus is

FBI Department of Defense virus is a dangerous ransomware, which is expected to replace FBI virus.

This threat is extremely consistent when it comes to scaring its victims and making them pay an invented fine of $300. Typically, it starts its activity by blocking down the system. It means that this virus is capable to block Internet connection, and hide all the files and folders.

In addition, FBI Department of Defense virus starts showing a huge notification, which seems like it belongs to Federal Bureau of Investigation and involves such details as victim's IP address, computer's location, operating system and similar.

No matter that it looks professionally, this alert is nothing but a scam, which seeks to scare PC users into paying a ransom. Please, never do that! You have to remove FBI Department of Defense virus once you start seeing its alert.

FBI Department of Defense virus: 1
FBI Department of Defense virus in our 2021 report.

How FBI Department of Defense virus behaves

From our report of Apr 2021 · not reviewed since

HOW CAN I GET INFECTED WITH FBI Department of Defense virus?

FBI Department of Defense virus is downloaded onto the target PC by trojan horse, which is known as Trojan.Ransomlock.

This cyber threat is usually spread via spam, illegal websites and similar means that are used for spreading trojans. Once it gets inside, it blocks down the PC and starts showing this fake alert that reports about breaking down the laws of United States of America. It claims:

Remember, FBI uses much more serious methods when trying to make their criminals pay fines. If you see FBI Department of Defense alert on your computer, it means that your machine is infected with virus, which seeks to swindle $300. Please, never do that! Instead of that, follow a detailed guide, which is given below, and remove this ransomware from the system.

The FBI Department of Defense virus ransom note

Text of help09.html

Mandiant U.S.A. Cyber Security

FBI. Department of Defense

U.S.A. Cyber Crime Center

Interpol

Attention!

Your computer has been blocked for safety reasons listed below.

You are accused of viewing/storage and/or dissemination of banned pornography (child pornography/zoophilia/rape etc). You have violated World Declaration on non-proliferation of child pornography. You are accused of committing the crime envisaged by Article 161 of United States of America criminal law.

(...)

How to remove FBI Department of Defense virus

Tools you'll need

All of these are free except where noted. Download them on a clean device if the infected PC is offline.

  • A USB stick: to keep the ransom note, two or three encrypted files and screenshots off the infected PC.
  • Microsoft Defender Offline: built into Windows 11 and Windows 10; scans before Windows starts, so running malware cannot hide.
  • Microsoft Safety Scanner: a second, portable scanner with current signatures; each download works for 10 days.
  • ID Ransomware: identifies the family from the note and one encrypted file and says whether a decryptor exists.
  • No More Ransom: the free decryptors from police and security companies; check it again every few months.
  • Fortect (optional): scans Windows for malware and repairs the system files and settings it damaged. The free scan is in the box above.

How to remove FBI Department of Defense virus and get your files back

Work in this order.

Disconnecting comes first, removal comes before any restore, and nothing here asks you to contact the attackers.

  1. Step 1: Disconnect the PC and unplug backup drives

    FBI Department of Defense virus encrypts everything it can reach, including drives and shares you connect later. Cut the network first: cable out, or Wi-Fi off from the taskbar.

    Then unplug every USB stick and backup disk and pause cloud sync, so the encrypted versions do not replace your online copies. Do not reconnect any of them until the ransomware is removed from the Windows 11 or Windows 10 PC.

    Windows 11 quick settings with Wi-Fi turned off
    Windows 11: turn off Wi-Fi to take the PC offline.

    Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files

  2. Step 2: Save the ransom note and identify the family

    Find the ransom note, usually a .txt, .html or .hta file in every folder or on the desktop, and copy it with one or two encrypted files to a USB stick.

    From another device, upload them to ID Ransomware or No More Ransom's Crypto Sheriff, which name the family from the note and the file extension. Write down the contact address and your personal ID from the note for the report.

    Warning: Never contact the attackers from the infected Windows 11 or Windows 10 PC.

    A ransom note text file next to encrypted files in File Explorer
    Windows 11: the ransom note and encrypted files to copy for identification.

    Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files

  3. Step 3: Check for a free decryptor

    For FBI Department of Defense virus, no free decryptor is known (checked 7 October 2026). Search the family name in the No More Ransom decryption tools list and in the free decryptors of Emsisoft, Avast and Kaspersky, because new tools appear years after an attack.

    Important: Keep the encrypted files even if nothing works today, and do not pay before every free option is ruled out: payment does not guarantee a working key.

    Decryptors run on Windows 11 and Windows 10, but only after the ransomware itself is removed.

    Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files

  4. Step 4: Remove the ransomware before you restore or decrypt

    Restoring or decrypting files while FBI Department of Defense virus still runs lets it encrypt them again. Run a Full scan in Windows Security > Virus & threat protection > Scan options, then the Microsoft Defender Antivirus (offline scan).

    If the ransomware blocks Windows Security, start Safe Mode with Networking and scan from there. Some families install a password stealer as well, so let both scans finish on Windows 11 or Windows 10.

    Windows Security Scan options with Microsoft Defender Antivirus offline scan selected
    Windows 11: Windows Security > Virus & threat protection > Scan options.

    Full procedure with screenshots: Run a Microsoft Defender Offline scan

  5. Step 5: Look for shadow copies of the files

    Open Command Prompt as administrator and run vssadmin list shadows. If it lists copies dated before the attack, right-click a folder with encrypted files in File Explorer, choose Properties > Previous Versions, and open or restore a version from before that date.

    ShadowExplorer, a free tool, shows the same copies when the tab is empty or hidden. Most current families delete shadow copies, so an empty list is normal, but the check takes two minutes on Windows 11 or Windows 10.

    Command Prompt running vssadmin list shadows
    Windows 11: vssadmin list shadows shows whether shadow copies exist.

    Full procedure with screenshots: Ransomware: first steps, finding a decryptor and recovering files

  6. Step 6: Restore the files from a backup or recover deleted originals

    Restore from an external backup, File History or OneDrive's version history, choosing a date before the attack. Connect the backup drive only after the scans are clean, or the ransomware encrypts it too.

    If there is no backup, file recovery software can sometimes find the deleted originals, because some ransomware writes an encrypted copy and deletes the original file.

    Stop writing to the drive and try recovery on Windows 11 or Windows 10 before new files overwrite the space.

    Full procedure with screenshots: Recover deleted files (Recycle Bin, backups, OneDrive) On uGetFix

From our report of Apr 2021 · not reviewed since

HOW TO REMOVE FBI Department of Defense virus?

To unlock your computer and get the ability to scan it with the reputable anti-malware, follow these steps:

1. Take another machine and use it to download , or other reputable anti-malware program. 2. Update the program and put into the USB drive or simple CD.

3. In the meanwhile, reboot your infected machine to Safe Mode with command prompt and stick USB drive in it. 4. Reboot computer infected with FBI Department of Defense virus once more and run a full system scan.

* Users infected with FBI Department of Defense virus are allowed to access other accounts on their Windows systems. If one of such accounts has administrator rights, you should be capable to launch anti-malware program.

* Try to deny the Flash to make your ransomware stop function as intended. In order to disable the Flash, go to Macromedia support and select 'Deny': http://www.macromedia.com/support/documentation/en/flashplayer/help/help09.html. After doing that, run a full system scan with anti-malware program.

* Manual FBI Department of Defense virus removal:

  • Reboot you infected PC to 'Safe mode with command prompt' to disable FBI virus (this should be working with all versions of this threat)
  • Run Regedit
  • Search for WinLogon Entries and write down all the files that are not explorer.exe or blank. Replace them with explorer.exe.
  • Search the registry for these files you have written down and delete the registry keys referencing the files.
  • Reboot and run a full system scan with updated anti-spyware to remove remaining Mandiant USA Cyber Security virus files.

Report it and recover your files

Report it

Report the attack even if you do not expect the files back: insurers and banks ask for the report number, and police use the contacts in the note to link cases.

United States
FBI IC3 · FTC ReportFraud

Give the victim ID, the note and the date the files were encrypted. A business that holds personal data may also have to notify its data protection authority, in the EU within 72 hours.

Protect the files you restore

Restore only after the scans are clean and the PC no longer shows ransom notes called help09.html in every folder; otherwise the restored copies can be damaged again.

Then build a backup that survives the next infection:

  • one copy in the cloud with version history
  • one on an external drive that is disconnected between backups
  • the working copy on the PC

Version history matters because a backup that syncs damaged files overwrites the good ones.

How to do this with the tools built into Windows: the 3-2-1 backup rule on Windows.

Protect your privacy - employ a VPN

There are several ways how to make your online time more private - you can access an incognito tab.

However, there is no secret that even in this mode, you are tracked for advertising purposes. There is a way to add an extra layer of protection and create a completely anonymous web browsing practice with the help of VPN. This software reroutes traffic through different servers, thus leaving your IP address and geolocation in disguise.

Besides, it is based on a strict no-log policy, meaning that no data will be recorded, leaked, and available for both first and third parties. The combination of a secure web browser and VPN will let you browse the Internet without a feeling of being spied or targeted by criminals.

No backups? No problem. Use a data recovery tool

If you wonder how data loss can occur, you should not look any further for answers - human errors, malware attacks, hardware failures, power cuts, natural disasters, or even simple negligence.

In some cases, lost files are extremely important, and many straight out panic when such an unfortunate course of events happen. Due to this, you should always ensure that you prepare proper data backups on a regular basis.

If you were caught by surprise and did not have any backups to restore your files from, not everything is lost. is one of the leading file recovery solutions you can find on the market - it is likely to restore even lost emails or data located on an external device.

Questions about FBI Department of Defense virus

When will a decryptor for FBI Department of Defense virus be released?

Nobody can promise a date. When we last checked, on 7 October 2026, no free decryptor is known. Decryptors usually appear after one of three events:

  • police seize the attackers' servers and keys
  • the authors leak or publish the master keys
  • researchers find a mistake in how the ransomware generates keys

Some families got a tool within weeks, others never. Keep the encrypted files and the note on an external drive, check No More Ransom every few months, and follow news about the FBI Department of Defense virus family. A decryptor may need an original file, so keep any unencrypted copies too.

Should I pay the ransom?

We advise against it, and so do the FBI, Europol and national cyber agencies. Payment does not guarantee a working tool: some attackers never reply, some tools damage files, and some variants have no decryptor at all. Paying also funds further attacks and can make you a target again.

Before considering payment, try every recovery option in this guide and report the attack. Companies must involve their legal adviser and insurer, because payments to sanctioned groups can be illegal. If files are truly irreplaceable, store the encrypted copies and wait; decryptors sometimes appear later.

How did FBI Department of Defense virus get on my computer?

The way FBI Department of Defense virus spreads has not been documented yet, so look at your own recent activity. On home PCs, ransomware most often comes with cracked programs, game cheats, key generators and fake updates, or with an e-mail attachment that was opened.

On business networks, attackers usually log in through Remote Desktop with a stolen or guessed password. Think back to what was downloaded or installed in the days before ransom notes called help09.html in every folder, and check the Downloads folder and Installed apps sorted by date. Keep anything suspicious for your report, but do not run it again.

Can a data-recovery company decrypt my files for a fee?

Only if a decryptor already exists or the company pays the attackers for you. Some "ransomware recovery" services advertise that they can decrypt families with no known flaw; in practice they negotiate with the attackers and add their own fee. Others use the same free tools listed on No More Ransom.

Before you hire anyone, ask in writing how they will recover the files, whether they will contact the attackers and what happens if they fail. A legitimate service answers clearly. If a free decryptor exists for your family, you can run it yourself.

Did FBI Department of Defense virus steal my files or passwords?

We do not know yet. Nothing published so far shows data theft by FBI Department of Defense virus, but the only confirmed sign is ransom notes called help09.html in every folder, which says nothing about what happened before. Many current ransomware attacks copy files or run a password stealer first, so it is wise to act as if they did.

From a clean device, change the passwords that were saved in the browsers on this PC, starting with e-mail and banking, sign out of all sessions and turn on two-step verification. Watch bank statements and account activity for the next few weeks.

Is FBI Department of Defense virus the same as other ransomware with a similar name?

Not necessarily. Ransomware names come from the file extension, the note or a word in the code, so unrelated families often end up with similar names, and one family can appear under several names. The difference matters: a decryptor or advice for one family does not fit another and can damage files.

Compare the ending added to your files and the exact name of the note with the summary table at the top of this guide, then upload the note and one encrypted file to ID Ransomware from a clean device. If the result names another family, follow the guide for that family instead.

Can I delete help09.html?

Yes, the note itself is harmless text and deleting it does not affect your files. Keep at least one copy first, outside the infected PC. help09.html contains your personal ID and the attackers' contact details, which identification services use to tell which family encrypted your files, and which a decryptor may need later.

Police reports also ask for it. Once you have saved a copy, you can remove the notes from every folder after the ransomware program has been removed and your files are restored or backed up.

Is help09.html from real ransomware or a bluff?

Look at your files rather than the note. If documents and photos have a new extension and will not open, the encryption is real. If files open normally, or only a few were renamed, the note may come from fake ransomware or extortion-only malware that claims more than it did.

Some wipers also leave notes like help09.html while destroying data with no way back. Identification services help here too: they recognise the note and tell you whether the family is known to encrypt, to bluff, or to wipe.

How do I open my .docx, .jpg and other files locked by FBI Department of Defense?

You cannot open locked files normally while they stay encrypted, and renaming them will not help. Our earlier report did not record the extension that FBI Department of Defense adds, so check one locked file name and the ransom note for it.

No free decryptor is known for this variant; check No More Ransom (nomoreransom.org) for updates. Do not rename the files, change the extension or edit them, because that can make recovery harder. Copy the locked files to an external drive before you clean the system, so a decryptor released later still has them.

Will Fortect remove FBI Department of Defense virus?

Fortect scans Windows for malware and unwanted programs and repairs the system files and settings they change, and its free scan shows what it finds on your PC before you decide anything.

For FBI Department of Defense virus, follow the plan above as well: the browser steps take back permissions and settings that no scanner treats as a threat, and uninstalling the program that brought it removes the source.

Run Microsoft Defender's full scan and, if anything was found, its offline scan as a second opinion. If the symptoms are gone after the plan and both scans are clean, there is nothing more to do.

Sources

  1. CISA: StopRansomware (read October 7, 2026)
  2. No More Ransom (read October 7, 2026)
  3. FTC: How to recognize, remove and avoid malware (read October 7, 2026)
  4. Microsoft Learn: Microsoft Defender Offline (read October 7, 2026)
  5. Microsoft Learn: How Microsoft names malware (read October 7, 2026)

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