meta infos in

  • picture.jpg
  • picture.tiff
  • picture.gif (according to Wiki not, but scroll down for an example)
  • but also movie.avi

… can contain quiet a lot of sensitive data:

  • what date the picture was taken
  • with what camera/phone (Samsung Galaxy S3 did that)
  • maybe even: GPS info/location of the picture
  • who/what tools processed the picture

of course as always, this data can be put to good or bad use

privacy wise it would be probably the best to simply delete it all

“According to documents leaked by Edward Snowden, the NSA is targeting Exif information under the XKeyscore program.[22]

“The privacy problem of Exif data can be avoided by removing the Exif data using a metadata removal tool.[23]

“Exif tag contains metadata about the photo, it can pose a privacy problem. For example, a photo taken with a GPS-enabled camera can reveal the exact location and time it was taken, and the unique ID number of the device – this is all done by default – often without the user’s knowledge.”

(prominent case: John McAfee was arrested in Guatemala

(after VICE Magazin journalists were unaware they were leaking their GPS location via picture Exif meta data … while this data can be used to find criminals… it could also endanger whistleblowers to cooperate with journalists that are unaware of Exif meta data in pictures)

a picture within a picture: “Photo manipulation software sometimes fails to update the embedded thumbnail after an editing operation, possibly causing the user to inadvertently publish compromising information.[13] For example, someone might blank out a licence registration plate of a car (for privacy concerns), only to have the thumbnail not so updated, meaning the information is still visible.” (src: wikipedia.org)

# gnu linux debian 10 tested
su - root;
apt update;
apt install libimage-exiftool-perl

# rpm/fedora/redhat/centos tested
yum update
yum install perl-Image-ExifTool.noarch



# show meta data of the above picture
exiftool Exif_meta_info_data_from_jpg_png_tiff_bmp_pictures.jpg
ExifTool Version Number         : 11.16
File Name                       : Exif_meta_info_data_from_jpg_png_tiff_bmp_pictures.jpg
Directory                       : .
File Size                       : 189 kB
File Modification Date/Time     : 2021:02:18 00:22:56+01:00
File Access Date/Time           : 2021:02:18 00:22:56+01:00
File Inode Change Date/Time     : 2021:02:18 00:22:56+01:00
File Permissions                : rw-r--r--
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
JFIF Version                    : 1.01
Exif Byte Order                 : Little-endian (Intel, II)
X Resolution                    : 300
Y Resolution                    : 300
Resolution Unit                 : inches
Software                        : GIMP 2.10.8
Modify Date                     : 2021:02:18 00:22:55
GPS Latitude                    : 0 deg 0' 0.00"
GPS Longitude                   : 0 deg 0' 0.00"
GPS Altitude                    : 0 m
Compression                     : JPEG (old-style)
Photometric Interpretation      : YCbCr
Samples Per Pixel               : 3
Thumbnail Offset                : 370
Thumbnail Length                : 10400
XMP Toolkit                     : XMP Core 4.4.0-Exiv2
Digital Source Type             : http://cv.iptc.org/newscodes/digitalsourcetype/digitalCapture
Document ID                     : gimp:docid:gimp:f5e2799d-1311-429c-a978-cd1abe2ee074 <- wtf is this?
Instance ID                     : xmp.iid:e5134e69-a909-4fc5-a0ba-d16d9a4e08ea <- wtf is this?
Original Document ID            : xmp.did:15edc5ad-7fe5-49a5-acec-a4f426ab35a1 <- wtf is this?
Model Release Status            : None
Api                             : 2.0
Platform                        : Linux
Time Stamp                      : 1613604176114808
Version                         : 2.10.8
Format                          : image/jpeg
Creator Tool                    : GIMP 2.10
Location Created                : 
Location Shown                  : 
Artwork Or Object               : 
Registry ID                     : 
History Action                  : saved, saved
History Changed                 : /metadata, /
History Instance ID             : xmp.iid:5f6344dd-69d6-4572-8bd7-67b5917ee436, xmp.iid:d8a8173d-ab29-497c-a95a-9a41ef119791
History Software Agent          : Gimp 2.10 (Linux), Gimp 2.10 (Linux)
History When                    : +01:00, +01:00
Image Supplier                  : 
Image Creator                   : 
Copyright Owner                 : 
Licensor                        : 
Description                     : The Matrix has you!
Title                           : EXIF-O-MATIC
Image Width                     : 1014
Image Height                    : 669
Encoding Process                : Progressive DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:4:4 (1 1)
Image Size                      : 1014x669
Megapixels                      : 0.678
Thumbnail Image                 : (Binary data 10400 bytes, use -b option to extract)
GPS Position                    : 0 deg 0' 0.00", 0 deg 0' 0.00"

exiftool example_image.jpg
ExifTool Version Number         : 11.16
File Name                       : example_image.jpg
Directory                       : .
File Size                       : 35 kB
File Modification Date/Time     : 2021:02:17 13:31:39+01:00
File Access Date/Time           : 2021:02:17 13:31:41+01:00
File Inode Change Date/Time     : 2021:02:17 13:31:39+01:00
File Permissions                : rw-r--r--
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
JFIF Version                    : 1.01
Exif Byte Order                 : Little-endian (Intel, II)
Image Description               : Processed By X with ImageMagick, z1.1.0. ||B2
X Resolution                    : 72
Y Resolution                    : 72
Resolution Unit                 : inches
Software                        : GIMP 2.10.8
Modify Date                     : 2021:02:17 13:31:39
User Comment                    : Processed By X with ImageMagick, z1.1.0. ||B2
Compression                     : JPEG (old-style)
Photometric Interpretation      : YCbCr
Samples Per Pixel               : 3
Thumbnail Offset                : 408
Thumbnail Length                : 5490
Image Width                     : 512
Image Height                    : 382
Encoding Process                : Progressive DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:4:4 (1 1)
Image Size                      : 512x382
Megapixels                      : 0.196
Thumbnail Image                 : (Binary data 5490 bytes, use -b option to extract)

# another example
exiftool example_image2.jpg
ExifTool Version Number         : 11.16
File Name                       : example_image2.jpg
Directory                       : .
File Size                       : 73 kB
File Modification Date/Time     : 2020:07:30 17:27:43+02:00
File Access Date/Time           : 2021:02:17 13:41:08+01:00
File Inode Change Date/Time     : 2021:02:17 13:41:08+01:00
File Permissions                : rw-r--r--
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
JFIF Version                    : 1.01
Exif Byte Order                 : Big-endian (Motorola, MM)
Orientation                     : Horizontal (normal)
X Resolution                    : 100
Y Resolution                    : 100
Resolution Unit                 : inches
Software                        : Paint.NET v3.5.2
Compression                     : JPEG (old-style)
Thumbnail Offset                : 232
Thumbnail Length                : 5286
Profile CMM Type                : Linotronic
Profile Version                 : 2.1.0
Profile Class                   : Display Device Profile
Color Space Data                : RGB
Profile Connection Space        : XYZ
Profile Date Time               : 1998:02:09 06:49:00
Profile File Signature          : acsp
Primary Platform                : Microsoft Corporation
CMM Flags                       : Not Embedded, Independent
Device Manufacturer             : Hewlett-Packard
Device Model                    : sRGB
Device Attributes               : Reflective, Glossy, Positive, Color
Rendering Intent                : Perceptual
Connection Space Illuminant     : 0.9642 1 0.82491
Profile Creator                 : Hewlett-Packard
Profile ID                      : 0
Profile Copyright               : Copyright (c) 1998 Hewlett-Packard Company
Profile Description             : sRGB IEC61966-2.1
Media White Point               : 0.95045 1 1.08905
Media Black Point               : 0 0 0
Red Matrix Column               : 0.43607 0.22249 0.01392
Green Matrix Column             : 0.38515 0.71687 0.09708
Blue Matrix Column              : 0.14307 0.06061 0.7141
Device Mfg Desc                 : IEC http://www.iec.ch
Device Model Desc               : IEC 61966-2.1 Default RGB colour space - sRGB
Viewing Cond Desc               : Reference Viewing Condition in IEC61966-2.1
Viewing Cond Illuminant         : 19.6445 20.3718 16.8089
Viewing Cond Surround           : 3.92889 4.07439 3.36179
Viewing Cond Illuminant Type    : D50
Luminance                       : 76.03647 80 87.12462
Measurement Observer            : CIE 1931
Measurement Backing             : 0 0 0
Measurement Geometry            : Unknown
Measurement Flare               : 0.999%
Measurement Illuminant          : D65
Technology                      : Cathode Ray Tube Display
Red Tone Reproduction Curve     : (Binary data 2060 bytes, use -b option to extract)
Green Tone Reproduction Curve   : (Binary data 2060 bytes, use -b option to extract)
Blue Tone Reproduction Curve    : (Binary data 2060 bytes, use -b option to extract)
Image Width                     : 477
Image Height                    : 407
Encoding Process                : Baseline DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:2:0 (2 2)
Image Size                      : 477x407
Megapixels                      : 0.194
Thumbnail Image                 : (Binary data 5286 bytes, use -b option to extract)

# another example from lineageOS on Nexus 6p
exiftool example_image3.jpg
ExifTool Version Number         : 11.16
File Name                       : example_image3.jpg
Directory                       : .
File Size                       : 778 kB
File Modification Date/Time     : 2021:02:17 13:46:18+01:00
File Access Date/Time           : 2021:02:17 13:49:50+01:00
File Inode Change Date/Time     : 2021:02:17 13:49:50+01:00
File Permissions                : rw-r--r--
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
JFIF Version                    : 1.01
Resolution Unit                 : None
X Resolution                    : 1
Y Resolution                    : 1
Profile CMM Type                : 
Profile Version                 : 2.1.0
Profile Class                   : Display Device Profile
Color Space Data                : RGB
Profile Connection Space        : XYZ
Profile Date Time               : 0000:00:00 00:00:00
Profile File Signature          : acsp
Primary Platform                : Unknown ()
CMM Flags                       : Not Embedded, Independent
Device Manufacturer             : 
Device Model                    : 
Device Attributes               : Reflective, Glossy, Positive, Color
Rendering Intent                : Media-Relative Colorimetric
Connection Space Illuminant     : 0.9642 1 0.82491
Profile Creator                 : 
Profile ID                      : 0
Profile Description             : sRGB
Red Matrix Column               : 0.43607 0.2225 0.01393
Green Matrix Column             : 0.38506 0.71687 0.09709
Blue Matrix Column              : 0.14307 0.06061 0.71417
Red Tone Reproduction Curve     : (Binary data 40 bytes, use -b option to extract)
Green Tone Reproduction Curve   : (Binary data 40 bytes, use -b option to extract)
Blue Tone Reproduction Curve    : (Binary data 40 bytes, use -b option to extract)
Media White Point               : 0.9642 1 0.82491
Profile Copyright               : Google Inc. 2016
Image Width                     : 3024
Image Height                    : 777
Encoding Process                : Baseline DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:2:0 (2 2)
Image Size                      : 3024x777
Megapixels                      : 2.3


# an gif metadata example
exiftool file.gif
ExifTool Version Number         : 12.00
File Name                       : file.gif
Directory                       : .
File Size                       : 6.1 MB
File Modification Date/Time     : 2020:02:13 20:52:17+01:00
File Access Date/Time           : 2020:08:07 08:54:40+02:00
File Inode Change Date/Time     : 2020:11:05 13:17:17+01:00
File Permissions                : rw-r--r--
File Type                       : GIF
File Type Extension             : gif
MIME Type                       : image/gif
GIF Version                     : 89a
Image Width                     : 500
Image Height                    : 250
Has Color Map                   : Yes
Color Resolution Depth          : 8
Bits Per Pixel                  : 8
Background Color                : 255
Animation Iterations            : Infinite
Frame Count                     : 81
Image Size                      : 500x250
Megapixels                      : 0.125

# another example for movie.avi
# exiftool can not remove meta data from avi
# "Error: Writing of AVI files is not yet supported"
exiftool movie.avi
ExifTool Version Number         : 11.16
File Name                       : movie.avi
Directory                       : .
File Size                       : 7.0 MB
File Modification Date/Time     : 2020:11:17 21:25:30+01:00
File Access Date/Time           : 2021:02:17 21:29:55+01:00
File Inode Change Date/Time     : 2021:02:17 23:17:37+01:00
File Permissions                : rw-r--r--
File Type                       : AVI
File Type Extension             : avi
MIME Type                       : video/x-msvideo
Frame Rate                      : 15.057
Max Data Rate                   : 307 kB/s
Frame Count                     : 396
Stream Count                    : 2
Stream Type                     : Video
Video Codec                     : mjpg
Video Frame Rate                : 15.057
Video Frame Count               : 396
Quality                         : 10000
Sample Size                     : Variable
BMP Version                     : Windows V3
Image Width                     : 320
Image Height                    : 240
Planes                          : 1
Bit Depth                       : 24
Compression                     : MJPG
Image Length                    : 230400
Pixels Per Meter X              : 0
Pixels Per Meter Y              : 0
Num Colors                      : Use BitDepth
Num Important Colors            : All
Audio Codec                     : 
Audio Sample Rate               : 8000
Audio Sample Count              : 210400
Encoding                        : Microsoft PCM
Num Channels                    : 1
Sample Rate                     : 8000
Avg Bytes Per Sec               : 8000
Bits Per Sample                 : 8
Date/Time Original              : 2006:06:24 18:47:00
Software                        : CASIO EX-Z40
Duration                        : 26.30 s
Image Size                      : 320x240
Megapixels                      : 0.077

# show metedata for all *jpg files in current dir
exiftool -ext jpg

# show metedata for all *jpg files in current dir and subdirs
exiftool -r -ext jpg .

# remove all metadata of a image file
exiftool -all= -overwrite_original example_image.jpg

# remove all metadata of all *jpg files in current dir
exiftool -all= -overwrite_original -ext jpg .

# remove metedata for all *jpg/*JPG files in current dir and subdirs
exiftool -all= -r -overwrite_original -ext jpg .

# remove metedata for all *png/*PNG files in current dir and subdirs
exiftool -all= -r -overwrite_original -ext png .

# remove metedata for all *bmp/*BMP files in current dir and subdirs
exiftool -all= -r -overwrite_original -ext bmp .

# remove metedata for all *gif/*GIF files in current dir and subdirs
exiftool -all= -r -overwrite_original -ext gif .

creditz:

http://xahlee.info/img/metadata_in_image_files.html

Links:

“The International Press Telecommunications Council (IPTC), based in London, United Kingdom, is a consortium of the world’s major news agencies, other news providers and news industry vendors and acts as the global standards body of the news media.” (src)

https://iptc.org/about-iptc/

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