Ransomware is a type of malicious software that encrypts files on a computer and demands payment from the victim in order to decrypt them. It has become an increasingly common and disruptive form of cyber attack. When ransomware infects a system, it often leaves users wondering if there is anything they can do to recover their files without paying the ransom. One tool that often comes to mind is System Restore.
System Restore is a built-in Windows feature that allows reverting the system back to an earlier restore point. Restore points are created automatically before major system changes and can also be created manually. This raises the question – can System Restore remove ransomware and recover encrypted files? Let’s take a detailed look at how System Restore works and its effectiveness against ransomware.
How does System Restore work?
System Restore monitors changes made to the system and creates restore points at certain intervals. This allows rolling back system files, registry keys, installed programs, etc. to a previous state. Restore points are created automatically:
- Before significant system events like installing software or drivers
- On a regular schedule determined by Windows
- When triggered manually by the user
Restore points contain information about system files as they existed at the time of creation. When initiated, System Restore replaces current system files and settings with the earlier versions stored in a selected restore point. This can be useful for undoing changes that caused problems.
However, System Restore does not affect personal files stored in user folders. It only monitors and recovers system files and settings.
Does System Restore remove ransomware?
Unfortunately, the answer is no. System Restore cannot help recover files encrypted by ransomware. There are a few reasons for this:
- System Restore only monitors system files and settings, not personal user data.
- Encrypted user files are still seen by the OS as normal unencrypted files.
- The encryption process does not make detectable changes at the system level.
- Restore points are created BEFORE ransomware infection, so infected files remain encrypted.
Even if you rolled back to a restore point created prior to infection, the encrypted user files will remain encrypted. This renders System Restore ineffective for dealing with ransomware.
Why doesn’t System Restore work against ransomware?
The key thing to understand is that ransomware only encrypts user data files, leaving system files untouched.
For example, on a Windows machine, ransomware encrypts documents, images, videos and other user files on the C drive. It does not modify or encrypt Windows system files.
From the operating system’s view, encrypted files are still seen as normal, unencrypted files. The encryption process does not make any high-level changes that System Restore can detect.
System Restore can only revert system files – like Windows registry keys and program files – to an earlier state. It cannot see that user files have been encrypted, and therefore cannot retrieve the previous unencrypted versions.
Can you recover files with System Restore?
Unfortunately, System Restore is completely ineffective when it comes to recovering ransomware encrypted files. Even if you roll back system files, settings and programs to a state prior to infection, your personal files will remain encrypted by the ransomware.
This is because System Restore cannot look into the contents of your personal files and determine they have been encrypted. It only sees them as normal files from the system level. The encryption process takes place directly within the user data files.
So System Restore, being limited to system files, cannot help undo the damage. It cannot access or recover previous versions of your personal files that have been encrypted.
Other options for ransomware file recovery
If System Restore does not help recover ransomware encrypted files, what other options exist? Here are some alternatives that may work in certain situations:
Cloud backups
If files were backed up to the cloud before the attack, the backups can be used to restore files after removing the ransomware. This is only effective if files aren’t synced during the infection, overwriting the backups.
Offline backups
Backups stored offline, e.g. external hard drives disconnected from the system, can provide access to clean file versions that can restore data after wiping the ransomware. As with cloud backups, care must be taken to avoid syncing infected files to the backups.
Shadow copies
Some ransomware families delete or encrypt Windows shadow copies of files. If available, software like ShadowExplorer can browse shadow copies and restore previous versions of files.
Decryption tools
For some ransomware families like GandCrab, decryption tools have been developed and made available for free public use. These tools can decrypt files without paying the ransom.
Antivirus software
Reputable cybersecurity software can detect and block many ransomware threats before encryption occurs. But this is only effective if installed and running up to date prior to infection.
Reinstalling the OS
As a last resort, completely wiping the system and reinstalling the operating system will eradicate the ransomware. But this also deletes all user files, leaving just backups for file recovery.
Best practices for preventing ransomware
While System Restore doesn’t help with ransomware file recovery, there are steps you can take to avoid becoming a victim in the first place:
- Install a reputable cybersecurity software solution and keep it updated.
- Be cautious of phishing emails and do not open attachments from unknown senders.
- Create backups of important files and store them disconnected from your system.
- Enable ransomware protection features in your antivirus if available.
- Avoid browsing websites you do not fully trust.
- Keep your OS and software up-to-date with the latest patches.
Can Shadow Copy restore ransomware files?
Windows Shadow Copy, also called Volume Snapshot Service (VSS), enables creating snapshots (“shadow copies”) of files at specific points in time. This can potentially allow recovering file versions encrypted by ransomware.
However, many ransomware variants attempt to disable and delete Shadow Copies specifically to block recovery. For example, the LockBit ransomware family includes the command “vssadmin Delete Shadows /All /Quiet” in its scripts to wipe out Shadow Copies.
If Shadow Copies survive ransomware infection, tools like ShadowExplorer may be able to browse and restore previous versions of encrypted files from before the attack. But preventing ransomware from tampering with Shadow Copies should be part of a comprehensive security strategy.
Maximizing Shadow Copy benefits
To maximize the potential benefits of Shadow Copies against ransomware:
- Ensure Volume Shadow Copy Service is enabled on local drives.
- Set the VSS storage location to another physical disk not visible to the OS.
- Limit Shadow Copies to 1 or 2 weekly copies to limit storage space used.
- Use a reputable cybersecurity software with ransomware behaviors detection.
With the right configuration and security controls, Shadow Copies can provide users an added layer of protection against ransomware attacks. However, they should not be relied on as a sole recovery method.
Does restoring from a previous version remove ransomware?
On Windows 10 and 11, users have the ability to restore specific files and folders to previous versions. Like Shadow Copies, this utilizes backup snapshots to revert files to an earlier state. However, there are significant limitations:
- Snapshots may not exist or be recent enough to recover critical files.
- Ransomware often deletes snapshots during encryption.
- Restoring files requires manually selecting previous versions one by one.
- System-wide rollbacks or automated recovery are not possible.
So while feasible in some cases, restoring previous file versions has limited value against ransomware and does not provide swift, reliable recovery across the system. It should not be the only recovery mechanism relied upon.
Can File History help restore encrypted files?
File History is a backup feature built into Windows 10 and 11 that continuously saves copies of files to an external drive. It enables users to restore previous versions of files that have changed or been deleted over time.
Like System Restore, File History does not directly protect against ransomware data encryption or help recover affected files. Its usefulness depends on:
- Backups pre-dating infection being retained and accessible.
- The external drive not being reached by ransomware to encrypt backups.
- The user having time and ability to manually locate and restore previous file versions.
File History alone does not provide an automated, system-wide ransomware recovery solution. It requires complementary security controls and user effort to restore files. However, as part of a multi-layered strategy, it can provide users an avenue to recover some encrypted files.
Can you stop ransomware with System Restore?
No, System Restore cannot stop or prevent ransomware from executing and encrypting files in real-time. This is due to the limitations of what System Restore monitors and recovers:
- System Restore only tracks and restores system files, not user data.
- It does not monitor or block processes from running in real-time.
- The encryption process does not make changes detected by System Restore.
- Restore points are created before infection, not during.
Since System Restore does not have insight into user data access/changes, ransomware is free to encrypt files unimpeded. Even if System Restore rolls back system files, the ransomware payload still leaves user files encrypted.
Effective ransomware protection requires real-time behavior monitoring, process blocking, and similar security controls typically provided by cybersecurity software solutions designed for that purpose.
Should you rely on System Restore for ransomware recovery?
System Restore can be useful for rolling back unwanted system changes that cause instability or problems. However, it should never be relied upon as a sole recovery mechanism against ransomware.
Due to its limitations, including inability to access or restore user files, System Restore does not provide effective protection or recovery from ransomware attacks.
Instead, a layered security approach should be followed, including:
- Backup files regularly to disconnected media.
- Use cybersecurity software with ransomware detection capabilities.
- Keep software updated and exercise caution with attachments/links.
- Utilize available filesystem backups like Volume Shadow Copy.
Ransomware resilience requires planning and robust security measures across the spectrum. No single tool like System Restore can be depended on independently to recover from ransomware. Take a layered, proactive approach to ransomware defense.
Conclusion
To summarize, System Restore is not capable of detecting, blocking or decrypting user files affected by ransomware encryption. Its capabilities are limited to restoring Windows system files and settings to earlier states.
Personal user files encrypted by ransomware remain encrypted after System Restore rollbacks. So do not rely solely on System Restore to recover ransomware-encrypted files. Ensure you are backing up important files regularly and taking proactive measures to avoid ransomware threats.
System Restore is simply the wrong tool for addressing ransomware attacks directly. A secure backup regimen coupled with cybersecurity software specifically designed against ransomware are necessary elements of an effective defense and recovery plan against modern ransomware threats.