Data wiping, also known as data clearing or data erasure, refers to securely deleting data from a storage device to make it unrecoverable (Wikipedia). It is typically done to protect sensitive personal or business data before disposing of, recycling or reusing a device. Data wiping overwrites the existing data with random data patterns multiple times to ensure the original data cannot be recovered.
Data wiping is designed to be an irreversible process so that wiped data cannot be retrieved by standard recovery methods. However, with the right tools and techniques, it is sometimes possible to recover fragments of wiped data, depending on how the wiping was performed and the storage technology used. This article will examine methods for securely wiping Android device data and the feasibility of recovering wiped data.
Android Data Storage
Android provides several options for storing data, both on the device itself and in the cloud. The main options for on-device storage are:
- Internal storage – This refers to the private storage space allocated for each app, typically located in the
/data/data/directory. Apps can save files directly to internal storage, and the files are accessible only to that app. Android uses the EXT4 file system for internal storage. - External storage – This refers to public storage space shared across apps, such as an SD card or adopted storage. The external storage uses the YAFFS2 file system on older devices, or EXT4 on newer ones. Files saved here are accessible by all apps.
In addition to local storage, apps can also leverage cloud storage services like Google Drive, Dropbox, etc. to store user data. The file systems and access controls used depend on the particular cloud service.
Understanding the different storage options is important for managing where sensitive data is kept. Internal storage offers better data protection, while external storage allows sharing between apps.
Data Wiping Methods
There are several ways to wipe data from an Android device:
Factory Reset
Performing a factory reset through the device settings is the most common method of wiping an Android device before selling or disposing of it. This resets the device back to its default factory settings and erases all user data (Source). However, it does not overwrite the data at the filesystem level.
Secure Wipe Apps and Features
There are dedicated apps like Android Device Manager that can perform a remote wipe of the device. Some Android versions also have a ‘Secure Wipe’ feature that overwrites data with zeros to prevent recovery (Source). However, their effectiveness depends on OEM implementation.
Manual Deletion and Reformatting
Users can also manually delete/format the device’s internal storage and SD card using a PC and recovery tools. This makes recovery difficult but still possible with forensic data recovery methods.
Challenges of Recovering Wiped Data
Recovering wiped data from Android devices can be challenging for several reasons:
First, when a file is deleted on Android, the space it previously occupied is marked as available to be overwritten by new data. The original file contents remain intact until they are overwritten by something else, but there is no guarantee when or if that will happen (Mashable, 2022). Overwriting makes recovery extremely difficult.
Second, performing a factory reset on an Android device often reformats the file system, changing how files are organized and stored. This restructuring can make it harder to reconstruct original file paths and recover data (MakeUseOf, 2023).
Finally, many newer Android devices use encryption to protect data. When encryption is enabled, data is scrambled and can only be accessed with the proper key or passphrase. Trying to recover wiped encrypted data without the decryption key is not feasible (Reddit, 2022).
In combination, overwriting, reformatting, and encryption present significant hurdles for recovering data from a wiped Android device using standard data recovery methods.
When Data Can Be Recovered
In some cases, it is possible to recover wiped data from Android devices. Here are some scenarios where data recovery may be successful:
If the data wiping process was interrupted before completion, such as if the phone battery died or the device crashed, then portions of the data may still be intact and recoverable. Performing a factory reset or wiping the data does not happen instantly, so if the process is disrupted, remnants of the original data may remain.
Additionally, data wiping methods do not always fully overwrite all the existing data. Depending on the technique used, some data traces may still exist and be recoverable by data recovery experts. Forensic data recovery methods can scan the raw storage media and reconstruct portions of deleted files and data.
If backups exist on external SD cards or cloud storage, it may be possible to restore data from a backup made prior to the wiping. However, any new data since the last backup will still be lost. Having a robust backup solution in place is important for protecting your data.
Data Recovery Software
There are several professional data recovery tools available for Android devices that can help recover lost or deleted data in many situations. Here are some of the top options:
Fonelab is a data recovery software designed specifically for Android devices. It can recover a wide range of data types including contacts, messages, call logs, photos, videos, audio files, documents and more. Fonelab supports data recovery from both internal storage and SD cards. It also claims a high recovery rate for even permanently deleted files.
EaseUS MobiSaver is another leading Android data recovery tool. It can recover photos, messages, contacts, and more from the internal memory of Android devices as well as SD cards. EaseUS MobiSaver also includes additional tools like phone-to-phone transfer and backup.
Dr.Fone offers data recovery for Android devices including the ability to recover deleted files, lost data from improper operations, factory reset protection and more. Dr.Fone claims to have a high recovery rate across various data types.
Overall, the top professional Android data recovery tools use advanced scanning and analysis to identify recoverable data. They support a wide range of data types and multiple recovery scenarios specific to Android devices. These tools help significantly expand the possibility for recovering lost or deleted data on Android phones or tablets.
Recovering Deleted Files
When files are deleted from Android devices, they are not immediately erased from the storage. Instead, they are simply marked as deleted in the file table, and the space they occupied becomes available to overwrite with new data. This means deleted files remain recoverable until they get overwritten.
To recover deleted files from internal storage, you can use data recovery apps like DiskDigger. These apps scan the raw storage and rebuild the file table to make deleted files accessible again. However, the sooner you run recovery, the higher the chances as old files get continuously overwritten over time. Root access allows recovery apps low-level access for better results.
For external SD cards, you can connect the SD card to a computer and use recovery software like Recuva to scan and restore deleted data. SD cards have lower risk of getting overwritten quickly compared to internal storage. But ideally, SD card recovery should also be done soon after deletion.
Recovering After Factory Reset
When you perform a factory reset on your Android device, it erases all user data from the internal storage and returns the device to its default settings. However, the wiped data still remains on the device until it gets overwritten by new data. Therefore, it is possible to recover deleted files from internal storage after a factory reset, before they get overwritten. According to IMOBIE (source), there are a few options to try:
– Use data recovery software like DiskDigger or EaseUS MobiSaver to scan the internal memory of your device and find recoverable deleted files after a factory reset. This method works for recovering photos, videos, audio files, documents etc.
– Check if the files were backed up to your Google account before the reset. Go to Settings > Accounts > Google and turn on sync. This will restore contacts, emails, calendar events etc. associated with that Google account.
For the external SD card, a factory reset does not touch its data. So the SD card contents remain intact after the reset. Just insert the SD card back into your Android device after the factory reset to access all the files again (source). An overall point to note is that the sooner you attempt data recovery after the factory reset, the higher the chances of recovering more data successfully.
Advanced Forensic Data Recovery
For advanced forensic data recovery from Android phones, specialists use a combination of hardware tools and software techniques to access and recover deleted data. Some key methods include:
Hardware tools to access storage chips – Forensic experts can remove the storage chip from an Android device and use chip readers to get a bit-for-bit copy of the raw data. This allows them to recover deleted files even if the phone is damaged or locked.
File carving – Forensic software scans the raw byte data looking for file signatures to carve out recoverable files. This can reconstruct images, documents, and other file types even if the original file system is corrupted.
Advanced data parsing – Experts use forensic tools to parse raw hex and binary data pulled from a device looking for data patterns like contacts, messages, geolocation, etc. This can recover deleted data not recoverable through file carving.
Bypassing screen locks – Hardware and software tools can bypass, disable or reset screen locks to allow data access on locked devices. This provides access to recover data when screen lock codes are unavailable.[https://www.flashbackdata.com/computer-forensics/mobile-forensics/]
Customized recovery methods – For unique situations, forensic experts will create customized software scripts and procedures to target the recovery of specific data from a particular device. This provides the best chance of recovering the needed data.[https://www.gillware.com/phone-data-recovery-services/android-forensics-services/]
Conclusion
Recovering data after it has been wiped from an Android device is often possible, but success depends on the method used to wipe the data and how much time has passed. While simple file deletions can usually be easily undone, more advanced techniques like factory resets put up more barriers to recovering data. However, with the right tools and techniques, forensic experts are frequently able to help users recover their lost data.
The key data recovery methods include using Android’s built-in recovery tools to restore recently deleted files, using data recovery apps to scan storage and rebuild deleted data, and performing advanced forensic analysis on device images to extract remnants of data. Each technique has its challenges and limitations, but used together they provide a good chance of recovering wiped data from Android devices.
With the large amounts of personal and business data stored on smartphones today, Android data recovery is an important tool for consumers and professionals alike. While no technique is foolproof, continuing innovation in data recovery software and forensic analysis means there are more options than ever for recovering lost data from Android devices, even after a factory reset or other wiping methods.