Recovering Deleted Files with PhotoRec
When to Use
- When recovering deleted files from a forensic disk image or storage device
- When the file system is corrupted, formatted, or overwritten
- During investigations requiring recovery of documents, images, videos, or databases
- When file system metadata is unavailable but raw data sectors remain intact
- For recovering files from memory cards, USB drives, and hard drives
Prerequisites
- PhotoRec installed (part of TestDisk suite)
- Forensic disk image or direct device access (read-only)
- Sufficient output storage space (potentially larger than source)
- Write-blocker if working with original media
- Root/sudo privileges for device access
- Knowledge of target file types for focused recovery
Workflow
Step 1: Install PhotoRec and Prepare the Environment
sudo apt-get install testdisk
sudo yum install testdisk
brew install testdisk
photorec --version
mkdir -p /cases/case-2024-001/recovered/{all,documents,images,databases}
file /cases/case-2024-001/images/evidence.dd
ls -lh /cases/case-2024-001/images/evidence.dd
Step 2: Run PhotoRec in Interactive Mode
photorec /cases/case-2024-001/images/evidence.dd
sudo photorec /dev/sdb
Step 3: Run PhotoRec with Command-Line Options for Targeted Recovery
photorec /d /cases/case-2024-001/recovered/documents/ \
/cmd /cases/case-2024-001/images/evidence.dd \
partition_table,options,mode,fileopt,search
photorec /d /cases/case-2024-001/recovered/documents/ \
/cmd /cases/case-2024-001/images/evidence.dd \
options,keep_corrupted_file,enable \
fileopt,everything,disable \
fileopt,doc,enable \
fileopt,docx,enable \
fileopt,pdf,enable \
fileopt,xlsx,enable \
search
photorec /d /cases/case-2024-001/recovered/images/ \
/cmd /cases/case-2024-001/images/evidence.dd \
fileopt,everything,disable \
fileopt,jpg,enable \
fileopt,png,enable \
fileopt,gif,enable \
fileopt,bmp,enable \
fileopt,tif,enable \
search
photorec /d /cases/case-2024-001/recovered/databases/ \
/cmd /cases/case-2024-001/images/evidence.dd \
fileopt,everything,disable \
fileopt,sqlite,enable \
fileopt,dbf,enable \
search
Step 4: Organize and Catalog Recovered Files
ls /cases/case-2024-001/recovered/all/
find /cases/case-2024-001/recovered/all/ -type f | \
sed 's/.*\.//' | sort | uniq -c | sort -rn > /cases/case-2024-001/recovered/file_type_summary.txt
cd /cases/case-2024-001/recovered/all/
for ext in jpg png pdf docx xlsx pptx zip sqlite; do
mkdir -p /cases/case-2024-001/recovered/sorted/$ext
find . -name "*.$ext" -exec cp {} /cases/case-2024-001/recovered/sorted/$ext/ \;
done
find /cases/case-2024-001/recovered/all/ -type f -exec sha256sum {} \; \
> /cases/case-2024-001/recovered/recovered_hashes.txt
find /cases/case-2024-001/recovered/all/ -type f \
-printf "%f\t%s\t%T+\t%p\n" | sort > /cases/case-2024-001/recovered/file_listing.txt
Step 5: Validate and Filter Recovered Files
find /cases/case-2024-001/recovered/all/ -type f -exec file {} \; \
> /cases/case-2024-001/recovered/file_signatures.txt
while IFS= read -r line; do
filepath=$(echo "$line" | cut -d: -f1)
filetype=$(echo "$line" | cut -d: -f2-)
ext="${filepath##*.}"
if [[ "$ext" == "jpg" ]] && ! echo "$filetype" | grep -qi "JPEG"; then
echo "MISMATCH: $filepath -> $filetype"
fi
done < /cases/case-2024-001/recovered/file_signatures.txt > /cases/case-2024-001/recovered/mismatches.txt
hashdeep -r -c sha256 /cases/case-2024-001/recovered/all/ | \
grep -vFf /opt/nsrl/nsrl_sha256.txt > /cases/case-2024-001/recovered/unknown_files.txt
find /cases/case-2024-001/recovered/all/ -type f -empty -delete
find /cases/case-2024-001/recovered/all/ -name "*.jpg" -exec jpeginfo -c {} \; 2>&1 | \
grep "ERROR" > /cases/case-2024-001/recovered/corrupted_images.txt
Key Concepts
| Concept | Description |
|---|
| File carving | Recovering files from raw data using file header/footer signatures |
| File signatures | Magic bytes at the start of files identifying their type (e.g., FF D8 FF for JPEG) |
| Unallocated space | Disk sectors not assigned to any active file; may contain deleted data |
| Fragmented files | Files stored in non-contiguous sectors; harder to carve completely |
| Cluster/Block size | Minimum allocation unit on a file system; affects carving granularity |
| File footer | Byte sequence marking the end of a file (not all formats have footers) |
| Data remanence | Residual data remaining after deletion until sectors are overwritten |
| False positives | Carved artifacts that match signatures but contain corrupted or partial data |
Tools & Systems
| Tool | Purpose |
|---|
| PhotoRec | Open-source file carving tool supporting 300+ file formats |
| TestDisk | Companion tool for partition recovery and repair |
| Foremost | Alternative file carver originally developed by US Air Force OSI |
| Scalpel | High-performance file carver based on Foremost |
| hashdeep | Recursive hash computation and audit tool |
| jpeginfo | JPEG file integrity verification |
| file | Unix utility identifying file types by magic bytes |
| exiftool | Extract metadata from recovered image and document files |
Common Scenarios
Scenario 1: Recovering Deleted Evidence from a Suspect's USB Drive
Image the USB drive with dcfldd, run PhotoRec targeting document and image formats, organize by file type, hash all recovered files, compare against known-bad hash sets, extract metadata from images for GPS and timestamp information.
Scenario 2: Formatted Hard Drive Recovery
Run PhotoRec in "Whole" mode against the entire formatted partition, recover all file types, expect higher false positive rate due to file fragmentation, validate recovered files with signature checking, catalog and hash for evidence chain.
Scenario 3: Memory Card from a Surveillance Camera
Recover deleted video files (AVI, MP4, MOV) from the memory card image, use targeted file type selection to speed recovery, verify video files are playable, extract frame timestamps, document recovery in case notes.
Scenario 4: Corrupted File System on Evidence Drive
When file system metadata is destroyed, PhotoRec bypasses the file system entirely and carves from raw sectors, recover maximum possible data, accept that file names and directory structure will be lost, rename files based on content during review.
Output Format
PhotoRec Recovery Summary:
Source Image: evidence.dd (500 GB)
Partition: NTFS (Partition 2)
Scan Mode: Free space only
Files Recovered: 4,523
Documents: 234 (doc: 45, docx: 89, pdf: 67, xlsx: 33)
Images: 2,145 (jpg: 1,890, png: 198, gif: 57)
Videos: 34 (mp4: 22, avi: 12)
Archives: 67 (zip: 45, rar: 22)
Databases: 12 (sqlite: 8, dbf: 4)
Other: 2,031
Data Recovered: 12.4 GB
Corrupted Files: 312 (flagged for review)
Output Directory: /cases/case-2024-001/recovered/all/
Hash Manifest: /cases/case-2024-001/recovered/recovered_hashes.txt
