Secure Virus Transfer for Analysis

G5 Cyber Security

1 week ago

TL;DR

Transferring a virus sample securely requires isolating it to prevent further infection, creating a bit-for-bit copy (image) of the storage medium, and then transferring that image – not the live file. Use tools like dd or dedicated imaging software. Verify the transfer with checksums.

Secure Virus Transfer for Analysis

Isolate the Server: Immediately disconnect the server from all networks (internet, LAN, Wi-Fi). This prevents the virus from spreading during the transfer process.
Identify the Storage Medium: Determine where the virus resides – hard drive, SSD, USB drive, etc. You need to copy the *entire* storage medium, not just individual files.
Create a Disk Image (Crucial Step): This is the safest method. A disk image is an exact replica of the storage device at a specific point in time. Do NOT attempt to copy the virus directly.
- Using dd (Linux/macOS): This command-line tool creates a bit-for-bit copy. Be *extremely* careful with this, as incorrect usage can overwrite data!
```
sudo dd if=/dev/sdX of=/path/to/imagefile.img bs=4M status=progress
```
Replace /dev/sdX with the correct device identifier (use lsblk to find it) and /path/to/imagefile.img with the desired location and filename for the image file.
Using Dedicated Imaging Software (Windows): Tools like FTK Imager, EnCase Forensic Imager, or AccessData Boxer provide a graphical interface and more safety features. Follow their documentation to create a forensic image.
Verify the Image: After creating the image, verify its integrity using checksums (MD5, SHA1, SHA256). This ensures the copy is identical to the original.
- Calculate Checksum on Original Medium: Use tools like md5sum or sha256sum (Linux/macOS) or HashCalc (Windows).
```
md5sum /dev/sdX
```
```
sha256sum /dev/sdX
```
- Calculate Checksum on Image File: Use the same tool to calculate the checksum of the image file.
```
md5sum /path/to/imagefile.img
```
```
sha256sum /path/to/imagefile.img
```
- Compare Checksums: The checksums *must* match exactly. If they don’t, the image is corrupted and you need to recreate it.
Secure Transfer of the Image File: Now that you have a safe copy (the disk image), transfer this file to the analysis location.
- Encrypted Storage: Use an encrypted USB drive or external hard drive. Tools like VeraCrypt can create encrypted containers.
- Secure File Transfer Protocol (SFTP): SFTP provides encrypted communication for transferring files over a network.
```
sftp user@remotehost
```
- Physical Transport: If possible, physically transport the storage device containing the image file. Ensure it remains secured during transit.
Analysis Environment: Perform all analysis within a completely isolated environment (virtual machine, sandbox) to prevent accidental infection of your primary systems.

Important Considerations:

Never run the virus directly on a production system.
Document every step of the process for forensic purposes.
Consider using write-blocking hardware when creating the disk image to prevent accidental modifications to the original medium.