Ikramer at 17:59, 14 June 2020

2020-06-14T17:59:25Z

← Older revision		Revision as of 17:59, 14 June 2020
Line 300:		Line 300:
	</div>		</div>

	[[Category:Privacy]]		[[Category:Privacy in IoT]]

JPDoe: Major: Initial Upload (by-product of ongoing investigations)

2020-06-14T13:09:04Z

Major: Initial Upload (by-product of ongoing investigations)

New page

<div style="max-width: 970px">

<div class="toccolours mw-collapsible mw-collapsed" style="border-color: #eaecf0; background-color: white; overflow:auto;">
<div style="font-weight: normal;line-height:1.6;">ⓘ Table of Contents</div>
<div class="mw-collapsible-content">
__TOC__
</div>
</div>

<h1>Summary</h1>
<table class="wikitable" style="width: 100%">
<tr><th style="text-align: left">Description</th><th style="text-align: left">Command</th></tr>
<tr><td><b>Show</b> Metadata</td><td><code>file /path/to/file</code></td></tr>
<tr><td><b>Show</b> extended Metadata</td><td><code>exiftool /path/to/file -v</code></td></tr>
<tr><td><b>Update</b> Metadata</td><td><code>exiftool /path/to/file -[TAG]=[VALUE]</code></td></tr>
<tr><td><b>Remove</b> Metadata</td><td><code>exiftool /path/to/file -[TAG]=</code></td></tr>
<tr><td><b>Remove ALL</b> unnecessary Metadata</td><td><code>exiftool /path/to/file -*=</code></td></tr>
</table>

<h1>Introduction</h1>
<p style="text-align: justify">When generating data with cameras, word processing, mailing or other programs that create files, the generation program adds extended attributes to a newly created or modified file. These attributes are part of the so-called <b>Metadata</b>. In most cases this information is added to a file without the user being aware of it or ever having to make use of it. Metadata includes the file name, creation date, or file type, which are fairly legitimate, but they can also take the form of the author of a text document, right down to information about the device that created it. In today's world, where digital cameras are built into our mobile devices and photos took with these are shared with our beloved and the rest of the Internet, sharing metadata can be a privacy issue as well, because it can leak information about the user themselves, their hardware or software. When focusing on images, a modern smartphone camera typically stores the device model, camera settings and often the location where the photo was taken, a so-called geotag. However, the last depends on the user's settings, which most inexperienced users will never notice or change. To preserve privacy and prevent the exposure of potentially vulnerable hardware or software, it's worth reassessing the benefits of metadata storage. As for the content of the file itself, it is possible to remove unwanted metadata.</p>

<div style="border: 1px solid #31708f; background-color: #d9edf7; color: #31708f; padding: 5px 10px; margin-bottom: 5px; text-align: justify"><b>Note</b>: Make sure to read this [https://www.cnet.com/how-to/remove-metadata-from-office-files-pdfs-and-images/ CNET article] about metadata included with emails, and how it can be used to gather personal information and patterns.</div>

<h1> Requirements</h1>
<p style="text-align: justify">On UNIX like systems like GNU-Linux or macOS the command <code>file</code>([https://linux.die.net/man/1/file man]) can be used to list the metadata included with the file. Additionaly when using macOS the command <code>xattr</code> ([https://man7.org/linux/man-pages/man7/xattr.7.html man]) or <code>getxattr</code> ([https://linux.die.net/man/2/getxattr man]) for GNU/Linux may reveal some additional metadata used by the operating system.</p>

<nowiki>
$ file ./LUPUS_XT2_Plus_PCB_Front.jpg

/path/to/file/LUPUS_XT2_Plus_PCB_Front.jpg: JPEG image data, JFIF standard 1.01, resolution (DPI), density 72x72, segment length 16, Exif Standard: [TIFF image data, little-endian, direntries=11, height=1867, </nowiki><b>manufacturer=samsung</b><nowiki>, </nowiki><b>model=SM-G965F</b><nowiki>, xresolution=164, yresolution=172, resolutionunit=2, </nowiki><b>software=PhotoScape</b><nowiki>, datetime=2020:02:24 19:14:16, width=2158], baseline, precision 8, 2158x1867, components 3</nowiki>

<div style="border: 1px solid #31708f; background-color: #d9edf7; color: #31708f; padding: 5px 10px; margin-bottom: 5px; text-align: justify"><b>Note</b>: Download this example image [https://wiki.elvis.science/images/4/4a/LUPUS_XT2_Plus_PCB_Front.jpg here].</div>

<p style="text-align: justify">Eventhough the metadata is easy to add and view, it is not so easy to remove it. A program that is able to do the job is Phil Harvey's <code>ExifTool</code> an can be installed using common package managers like <code>apt</code> for debian based systems or <code>brew</code> on macOS. Windows user can download the executable from the vendors webpage.</p>

<div style="border: 1px solid #31708f; background-color: #d9edf7; color: #31708f; padding: 5px 10px; margin-bottom: 5px; text-align: justify"><b>Description</b>: "ExifTool is a platform-independent [https://exiftool.org/ExifTool.html Perl library] plus a [https://exiftool.org/exiftool_pod.html command-line application] for reading, writing and editing meta information in a [https://exiftool.org/#supported wide variety of files]." <sup>[[https://exiftool.org source]]</sup></div>

<h1>Description</h1>
<div class="toccolours mw-collapsible mw-collapsed" style="border-color: #eaecf0; background-color: white; calc(100% - 12px); overflow:auto;">
<div style="line-height:1.6;">ⓘ <b>Show Metadata</b></div>
<div class="mw-collapsible-content">
<div style="font-size: 12px !important">
<nowiki>
$ exiftool -v LUPUS_XT2_Plus_PCB_Front.jpg

ExifToolVersion = 11.85
FileName = LUPUS_XT2_Plus_PCB_Front.jpg
Directory = .
FileSize = 3950536
FileModifyDate = 1592068395
FileAccessDate = 1592068396
FileInodeChangeDate = 1592068395
FilePermissions = 33188
FileType = JPEG
FileTypeExtension = JPG
MIMEType = image/jpeg
JPEG APP0 (14 bytes):
+ [BinaryData directory, 9 bytes]
| JFIFVersion = 1 1
| ResolutionUnit = 1
| XResolution = 72
| YResolution = 72
| ThumbnailWidth = 0
| ThumbnailHeight = 0
JPEG APP1 (842 bytes):
ExifByteOrder = II
+ [IFD0 directory with 11 entries]
| 0) ImageWidth = 2158
| 1) ImageHeight = 1867
| 2) </nowiki><b>Make = samsung</b><nowiki>
| 3) </nowiki><b>Model = SM-G965F</b><nowiki>
| 4) XResolution = 72 (72/1)
| 5) YResolution = 72 (72/1)
| 6) ResolutionUnit = 2
| 7) </nowiki><b>Software = PhotoScape</b><nowiki>
| 8) </nowiki><b>ModifyDate = 2020:02:24 19:14:16</b><nowiki>
| 9) YCbCrPositioning = 1
| 10) ExifOffset (SubDirectory) -->
| + [ExifIFD directory with 36 entries]
| | 0) ExposureTime = 0.02 (1/50)
| | 1) FNumber = 2.4 (240/100)
| | 2) ExposureProgram = 2
| | 3) ISO = 160
| | 4) ExifVersion = 0220
| | 5) </nowiki><b>DateTimeOriginal = 2020:02:24 19:14:16</b><nowiki>
| | 6) </nowiki><b>CreateDate = 2020:02:24 19:14:16</b><nowiki>
| | 7) ComponentsConfiguration = 1 2 3 0
| | 8) ShutterSpeedValue = 5.64 (564/100)
| | 9) ApertureValue = 2.52 (252/100)
| | 10) BrightnessValue = 2.36 (236/100)
| | 11) ExposureCompensation = 0 (0/10)
| | 12) MaxApertureValue = 1.16 (116/100)
| | 13) MeteringMode = 2
| | 14) Flash = 0
| | 15) FocalLength = 4.3 (430/100)
| | 16) </nowiki><b>UserComment =</b><nowiki>
| | 17) SubSecTime = 0020
| | 18) SubSecTimeOriginal = 0020
| | 19) SubSecTimeDigitized = 0020
| | 20) FlashpixVersion = 0100
| | 21) ColorSpace = 1
| | 22) ExifImageWidth = 2158
| | 23) ExifImageHeight = 1867
| | 24) InteropOffset (SubDirectory) -->
| | + [InteropIFD directory with 2 entries]
| | | 0) InteropIndex = R98
| | | 1) InteropVersion = 0100
| | 25) SceneType = .
| | 26) CustomRendered = 0
| | 27) ExposureMode = 0
| | 28) WhiteBalance = 0
| | 29) DigitalZoomRatio = undef (0/0)
| | 30) FocalLengthIn35mmFormat = 26
| | 31) SceneCaptureType = 0
| | 32) Contrast = 0
| | 33) Saturation = 0
| | 34) Sharpness = 0
| | 35) </nowiki><b>ImageUniqueID = I12LLKF00SM</b><nowiki>
JPEG DQT (65 bytes):
JPEG DQT (65 bytes):
JPEG SOF0 (15 bytes):
ImageWidth = 2158
ImageHeight = 1867
EncodingProcess = 0
BitsPerSample = 8
ColorComponents = 3
YCbCrSubSampling = 2 2
JPEG DHT (29 bytes):
JPEG DHT (179 bytes):
JPEG DHT (29 bytes):
JPEG DHT (179 bytes):
JPEG SOS</nowiki>
</div>
</div>
</div>

<div style="border: 1px solid #31708f; background-color: #d9edf7; color: #31708f; padding: 5px 10px; margin-bottom: 5px; text-align: justify; margin-top: 5px"><b>Note</b>: Make sure to checkout the [https://linux.die.net/man/1/exiftool man page] for additional cool features within the tool like the verbose mode (<code>-v</code>) or the multilanguage support (<code>-lang [COUNTRYCODE]</code>).</div>

<p style="text-align: justify">In this example scenario, I'd like to remove the <code>Make</code> (Camera Vendor), <code>Model</code> (Camera Model), <code>Software</code> (second stage editing tool), <code>ImageUniqueID</code> metadata as well as all timestamps from the example photo. To write or delete metadata, tag values are assigned using <code>-TAG=[VALUE]</code>, and/or the <code>-geotag</code> options. Additionally I'm going to do this operation for a bulk of photos.</p>

<div style="border: 1px solid #8a6d3b; background-color: #fcf8e3; color: #8a6d3b; padding: 5px 10px; margin-bottom: 5px; text-align: justify"><b>Warning</b>: Use the <code>-v</code> option to display the correct tag names used for modification or deletion!</div>

<div class="toccolours mw-collapsible" style="border-color: #eaecf0; background-color: white; calc(100% - 12px); overflow:auto;">
<div style="line-height:1.6;">ⓘ <b>Remove Metadata</b></div>
<div class="mw-collapsible-content">
<div style="font-size: 12px !important">
<nowiki>$ exiftool LUPUS_XT2_Plus_*.jpg -Make= -Software= -Model= -ImageUniqueID=</nowiki>
</div>
</div>
</div>

<div class="toccolours mw-collapsible" style="border-color: #eaecf0; background-color: white; calc(100% - 12px); overflow:auto;">
<div style="line-height:1.6;">ⓘ <b>Update Metadata</b></div>
<div class="mw-collapsible-content">
<div style="font-size: 12px !important">
<nowiki>
# Update multiple files at the same time
$ exiftool LUPUS_XT2_Plus_*.jpg -Comment="Hello darkness my old friend"

# Always update timestamps last
$ exiftool LUPUS_XT2_Plus_*.jpg -CreateDate="1970:01:01 00:00:00" -DateTimeOriginal="1970:01:01 00:00:00" -ModifyDate="1970:01:01 00:00:00"</nowiki>
</div>
</div>
</div>

<div class="toccolours mw-collapsible mw-collapsed" style="border-color: #eaecf0; background-color: white; calc(100% - 12px); overflow:auto;">
<div style="line-height:1.6;">ⓘ <b>Check modifications</b></div>
<div class="mw-collapsible-content">
<div style="font-size: 12px !important">
<nowiki>
$ exiftool LUPUS_XT2_Plus_PCB_Back.jpg
ExifTool Version Number : 11.85
File Name : LUPUS_XT2_Plus_PCB_Back.jpg
Directory : .
File Size : 3.2 MB
File Modification Date/Time : 2020:06:13 20:30:20+02:00
File Access Date/Time : 2020:06:13 20:30:22+02:00
File Inode Change Date/Time : 2020:06:13 20:30:21+02:00
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 : 72
Y Resolution : 72
Resolution Unit : inches
Modify Date : 1970:01:01 00:00:00
Y Cb Cr Positioning : Centered
Exposure Time : 1/50
F Number : 2.4
Exposure Program : Program AE
ISO : 200
Exif Version : 0220
Date/Time Original : </nowiki><b>1970:01:01 00:00:00</b><nowiki>
Create Date : </nowiki><b>1970:01:01 00:00:00</b><nowiki>
Components Configuration : Y, Cb, Cr, -
Shutter Speed Value : 1/50
Aperture Value : 2.4
Brightness Value : 1.99
Exposure Compensation : 0
Max Aperture Value : 1.5
Metering Mode : Center-weighted average
Flash : No Flash
Focal Length : 4.3 mm
User Comment :
Sub Sec Time : 0456
Sub Sec Time Original : 0456
Sub Sec Time Digitized : 0456
Flashpix Version : 0100
Color Space : sRGB
Exif Image Width : 2158
Exif Image Height : 1867
Interoperability Index : R98 - DCF basic file (sRGB)
Interoperability Version : 0100
Scene Type : Unknown (.)
Custom Rendered : Normal
Exposure Mode : Auto
White Balance : Auto
Digital Zoom Ratio : undef
Focal Length In 35mm Format : 26 mm
Scene Capture Type : Standard
Contrast : Normal
Saturation : Normal
Sharpness : Normal
Comment : </nowiki><b>Hello darkness my old friend</b><nowiki>
Image Width : 2158
Image Height : 1867
Encoding Process : Baseline DCT, Huffman coding
Bits Per Sample : 8
Color Components : 3
Y Cb Cr Sub Sampling : YCbCr4:2:0 (2 2)
Aperture : 2.4
Image Size : 2158x1867
Megapixels : 4.0
Scale Factor To 35 mm Equivalent: 6.0
Shutter Speed : 1/50
Create Date : </nowiki><b>1970:01:01 00:00:00.0456</b><nowiki>
Date/Time Original : </nowiki><b>1970:01:01 00:00:00.0456</b><nowiki>
Modify Date : </nowiki><b>1970:01:01 00:00:00.0456</b><nowiki>
Circle Of Confusion : 0.005 mm
Field Of View : 69.4 deg
Focal Length : 4.3 mm (35 mm equivalent: 26.0 mm)
Hyperfocal Distance : 1.55 m
Light Value : 7.2
</nowiki>
</div>
</div>
</div>

<div style="border: 1px solid #31708f; background-color: #d9edf7; color: #31708f; padding: 5px 10px; margin-bottom: 5px; text-align: justify; margin-top: 5px"><b>Note</b>: The tool will store by default a copy of the original file under the same name ending <code>_original</code>.</div>
<div style="border: 1px solid #8a6d3b; background-color: #fcf8e3; color: #8a6d3b; padding: 5px 10px; margin-bottom: 5px; text-align: justify"><b>Warning</b>: Be sure to verify that the new files are OK before erasing the originals. Once in write mode, exiftool will ignore any read-specific options.</div>

<h1>Maximus Paranoism</h1>

<p style="text-align: justify">A camera pro may be able to still identfy the camera or the type of device by the remaining metadata. For the more paranoid, consider removing ALL metadata using <code>-*=</code> and you may also want to change local creation, modification, access file timestamps using <code>touch</code>. Read the article [https://www.shellhacks.com/fake-file-access-modify-change-timestamps-linux/ Linux – Fake File Access, Modify and Change TimeStamps] for more information.</p>

<div class="toccolours mw-collapsible mw-collapsed" style="border-color: #eaecf0; background-color: white; calc(100% - 12px); overflow:auto;">
<div style="line-height:1.6;">ⓘ <b>Remove ALL unnecessary Metadata</b></div>
<div class="mw-collapsible-content">
<div style="font-size: 12px !important">
<nowiki>
$ exiftool LUPUS_XT2_Plus_PCB_Back.jpg -*=
$ exiftool LUPUS_XT2_Plus_PCB_Back.jpg

ExifTool Version Number : 11.85
File Name : LUPUS_XT2_Plus_PCB_Back.jpg
Directory : .
File Size : 3.2 MB
File Modification Date/Time : 2020:06:13 20:35:41+02:00
File Access Date/Time : 2020:06:13 20:36:03+02:00
File Inode Change Date/Time : 2020:06:13 20:36:02+02:00
File Permissions : rw-r--r--
File Type : JPEG
File Type Extension : jpg
MIME Type : image/jpeg
Image Width : 2158
Image Height : 1867
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 : 2158x1867
Megapixels : 4.0
</nowiki>
</div>
</div>
</div>

<h1>References</h1>
<p style="text-align: justify">
* https://exiftool.org
* https://linux.die.net/man/1/exiftool
* https://linux.die.net/man/1/file
* https://www.cnet.com/how-to/remove-metadata-from-office-files-pdfs-and-images/
* https://www.shellhacks.com/fake-file-access-modify-change-timestamps-linux/
</p>

</div>

[[Category:Privacy]]

Remove unnecessary Metadata from Files - Revision history

Ikramer at 17:59, 14 June 2020

JPDoe: Major: Initial Upload (by-product of ongoing investigations)