[HOWTO] Exifdata - What is it and how can I get rid of it?

 What is EXIF data?

EXIF is short for Exchangeable Image File, a format that is a standard for storing interchange information in digital photography image files using JPEG compression. Almost all new digital cameras use the EXIF annotation, storing information on the image such as shutter speed, exposure compensation, F number, what metering system was used, if a flash was used, ISO number, date and time the image was taken, whitebalance, auxiliary lenses that were used and resolution. Some images may even store GPS information so you can easily see where the images were taken! All this information is stored as metadata in the picture. It is invisible at first glance, meaning that when viewing the picture with you default picture viewer, this information is usually hidden. But it is also easily retrievable. People with our hobby really want to get rid of this information.

I will try to demonstrate with hands-on examples how to view and later on delete all this excessive data, making the publishing of your pictures on sites like ours a lot safer.

Examples

This is an EXIF-rich photo, which means it contains a lot of extra info I talked about in the intro.

I downloaded the image and I used 2 tools (Linux) to analyze the picture: exiftool and okteta. Okteta is a hexeditor for KDE. You can use other that better fit your desktop variant. (there is Ghex for Gnome (used by Tails) and also some other terminal hex-editors. A search will give you plenty of results) Exiftool is a Command Line utility and Okteta a Graphical one.

ExifTools

First I use Exiftool:

exiftool DSCN0010.jpg

The output is this (I edited some info for my own opsec):

ExifTool Version Number         : xx.xx
File Name                       : DSCN0010.jpg
Directory                       : .
File Size                       : 158 kB
File Modification Date/Time     : 2020:04:19 xxxxxxxxxx
File Access Date/Time           : 2020:04:19 xxxxxxxxxxxx
File Inode Change Date/Time     : 2020:04:19 xxxxxxxxxxx
File Permissions                : rw-rw-r--
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
Exif Byte Order                 : Little-endian (Intel, II)
Image Description               : 
Make                            : NIKON
Camera Model Name               : COOLPIX P6000
Orientation                     : Horizontal (normal)
X Resolution                    : 300
Y Resolution                    : 300
Resolution Unit                 : inches
Software                        : Nikon Transfer 1.1 W
Modify Date                     : 2008:11:01 21:15:07
Y Cb Cr Positioning             : Centered
Exposure Time                   : 1/75
F Number                        : 5.9
Exposure Program                : Program AE
ISO                             : 64
Exif Version                    : 0220
Date/Time Original              : 2008:10:22 16:28:39
Create Date                     : 2008:10:22 16:28:39
Components Configuration        : Y, Cb, Cr, -
Exposure Compensation           : 0
Max Aperture Value              : 2.7
Metering Mode                   : Multi-segment
Light Source                    : Unknown
Flash                           : Off, Did not fire
Focal Length                    : 24.0 mm
Maker Note Version              : 2.10
Color Mode                      : Color
Quality                         : Fine
White Balance                   : Auto
Focus Mode                      : AF-S
Flash Setting                   : 
ISO Selection                   : Auto
Data Dump                       : (Binary data 2542 bytes, use -b option to extract)
Face Detect Frame Size          : 320 240
Faces Detected                  : 0
Active D-Lighting               : Off
Image Adjustment                : Normal
Tone Comp                       : Normal
Auxiliary Lens                  : Off
Digital Zoom                    : 1
AF Area Mode                    : Single Area
AF Point                        : Center
AF Points In Focus              : (none)
Scene Mode                      : 
Distortion Control              : Off
Saturation Adj                  : 0
Noise Reduction                 : Off
Scene Assist                    : 
Date Stamp Mode                 : Off
Retouch History                 : None
Image Stabilization             : VR-On
Picture Control Version         : 0100
Picture Control Name            : Standard
Picture Control Base            : Standard
Picture Control Adjust          : Default Settings
Picture Control Quick Adjust    : Normal
Brightness                      : n/a
Hue Adjustment                  : n/a
Filter Effect                   : n/a
Toning Effect                   : n/a
Toning Saturation               : n/a
Nikon Capture Version           : COOLPIX P6000V1.0
NEF Bit Depth                   : n/a (JPEG)
User Comment                    : 
Flashpix Version                : 0100
Color Space                     : sRGB
Exif Image Width                : 640
Exif Image Height               : 480
Interoperability Index          : R98 - DCF basic file (sRGB)
Interoperability Version        : 0100
File Source                     : Digital Camera
Scene Type                      : Directly photographed
Custom Rendered                 : Normal
Exposure Mode                   : Auto
Digital Zoom Ratio              : 0
Focal Length In 35mm Format     : 112 mm
Scene Capture Type              : Standard
Gain Control                    : None
Contrast                        : Normal
Saturation                      : Normal
Sharpness                       : Normal
Subject Distance Range          : Unknown
GPS Latitude Ref                : North
GPS Longitude Ref               : East
GPS Altitude Ref                : Above Sea Level
GPS Time Stamp                  : 14:27:07.24
GPS Satellites                  : 06
GPS Img Direction Ref           : Unknown ()
GPS Map Datum                   : WGS-84
GPS Date Stamp                  : 2008:10:23
Compression                     : JPEG (old-style)
Thumbnail Offset                : 4560
Thumbnail Length                : 6702
Image Width                     : 640
Image Height                    : 480
Encoding Process                : Baseline DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:2:2 (2 1)
XMP Toolkit                     : Public XMP Toolkit Core 3.5
Rating Percent                  : 0
Aperture                        : 5.9
Image Size                      : 640x480
Megapixels                      : 0.307
Scale Factor To 35 mm Equivalent: 4.7
Shutter Speed                   : 1/75
Thumbnail Image                 : (Binary data 6702 bytes, use -b option to extract)
GPS Date/Time                   : 2008:10:23 14:27:07.24Z
GPS Latitude                    : 43 deg 28' 2.81" N
GPS Longitude                   : 11 deg 53' 6.46" E
Circle Of Confusion             : 0.006 mm
Field Of View                   : 18.3 deg
Focal Length                    : 24.0 mm (35 mm equivalent: 112.0 mm)
GPS Position                    : 43 deg 28' 2.81" N, 11 deg 53' 6.46" E
Hyperfocal Distance             : 15.16 m
Light Value                     : 12.0

As you can see there is a LOT of info to behold. Even GPS coordinates! Later on we all gonna clean this up!

Okteta (hexeditor)

Now I go a little further. We are going to use a hex-editor on the image to find some more secrets.

It isn't uncommon for a picture, especially EXIF-rich pictures to have 'hidden' inside it, 1 or more smaller pictures, or thumbnails. A hex-editor can 'prove' this existence pretty easily if you know where to look for. Every JPG has a hex code with indicates the 'start' of the actual image. For JPG this is FFD8FF The following GIF demonstrates how to use:

So here we can clearly see 1 other (smaller) pictures is 'hidden' within the original picture. Why is this important? Because when you, for instance, want to obfuscate a part of the image, say a pair of eyes, depending on the editor that is used, this could only do that for the original big picture and not the smaller, hidden one. That could be a problem! A lot of times the thumbnail will change accordingly, but better safe than sorry. So that was another reason to strip your pictures of metadata/exifdata.

You talk too much! Show me the Magic!

Ok, you ungrateful bastards. Here's your TL;DR To get rid of all this junk, there is a simple one-liner that kills it all:

Exiftool:

exiftool -all= DSCN0010.jpg

wildcards may be used for batch:

exiftool -all= *.jpg

Compare after scrubbing:

ExifTool Version Number         : xx.xx

File Name                       : DSCN0010.jpg

Directory                       : .

File Size                       : 143 kB

File Modification Date/Time     : 2020:04:19 xxxxxxxxx

File Access Date/Time           : 2020:04:19 xxxxxxxxx

File Inode Change Date/Time     : 2020:04: xxxxxxxxx

File Permissions                : rw-rw-r--

File Type                       : JPEG

File Type Extension             : jpg

MIME Type                       : image/jpeg

Image Width                     : 640

Image Height                    : 480

Encoding Process                : Baseline DCT, Huffman coding

Bits Per Sample                 : 8

Color Components                : 3

Y Cb Cr Sub Sampling            : YCbCr4:2:2 (2 1)

Image Size                      : 640x480

Megapixels                      : 0.307

This should work for all common image types (jpg, png etc) and also for MP4 video.

Enjoy!

Share on Google Plus

About KhmerueTeams Official

Welcome to KhmerueTeams Officials Blogger. I am Mr. Chhuye The Admin of this blogger. If you have quetion contact me : +855968555664 / +855976235033 or watch my video on ​

YOUTUBE HERE