Forums
New posts
Search forums
News
Security News
Technology News
Giveaways
Giveaways, Promotions and Contests
Discounts & Deals
Reviews
Users Reviews
Video Reviews
Support
Windows Malware Removal Help & Support
Inactive Support Threads
Mac Malware Removal Help & Support
Mobile Malware Removal Help & Support
Blog
Log in
Register
What's new
Search
Search titles only
By:
Search titles only
By:
Reply to thread
Menu
Install the app
Install
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
Software
Security Apps
Kaspersky
Think you know how to hide info in images?
Message
<blockquote data-quote="Bot" data-source="post: 873311" data-attributes="member: 52014"><p>You have probably had to conceal information in an image on at least one occasion. For example, the tech support guy didn’t need to see your personal data in a screenshot illustrating your issue. Or you wanted to avoid complaints from a passerby in a wedding shot. Or you wanted to show off your <a href="https://www.kaspersky.com/blog/never-post-barcodes-online/12842/" target="_blank">ticket to a long-awaited show</a> on Instagram, but do so with the barcode hidden in case someone else fancied going in your place.</p><p></p><p>Bear in mind, however, that blurred — and even cropped! — images can often still reveal the very data you wanted to hide. Here are five ways you could leak your own private information without even suspecting it.</p><p></p><p><span style="font-size: 18px"><strong>Mistake 1: Editing images in Office apps</strong></span></p><p></p><p></p><p>This is a classic way to inadvertently share personal or corporate secrets. If the image is for a text document or slide deck, the most convenient way to edit it is directly in the Office application. Just insert the image, crop the part you don’t want to show, save the document, and hand it over to the boss or client with a clear conscience.</p><p></p><p>The problem is that this just changes how the picture appears in the body of the document. The original image remains intact! To see the hidden part, all someone has to do is select the image and then the <em>Crop</em> tool on the <em>Format</em> tab.</p><p></p><p><a href="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130846/how-to-leak-image-info-screen-1-en.png" target="_blank"><img src="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130846/how-to-leak-image-info-screen-1-en.png" alt="Cropped images in Word ... " class="fr-fic fr-dii fr-draggable " style="" /></a></p><p>Cropped images in Word …</p><p></p><p><a href="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130855/how-to-leak-image-info-screen-2-en.png" target="_blank"><img src="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130855/how-to-leak-image-info-screen-2-en.png" alt="... are in fact saved intact" class="fr-fic fr-dii fr-draggable " style="" /></a></p><p>… are in fact saved intact</p><p></p><p></p><p>Good news: You can permanently remove superfluous parts of an image in a document using the <em>Compress Pictures</em> button on the same <em>Format</em> tab. Click it and make sure that the <em>Delete cropped areas of pictures</em> box is selected.</p><p></p><p><a href="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130901/how-to-leak-image-info-screen-3-en.png" target="_blank"><img src="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130901/how-to-leak-image-info-screen-3-en.png" alt="Use the Compress Pictures tool to remove sensitive information" class="fr-fic fr-dii fr-draggable " style="" /></a></p><p>Use the Compress Pictures tool to remove sensitive information</p><p></p><p></p><p>As for black rectangles and various graphic effects, these are of no use at all in Office applications. To see what lies beneath, the recipient can simply remove this superficial artwork.</p><p></p><p><a href="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130908/how-to-leak-image-info-screen-4-en.png" target="_blank"><img src="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130908/how-to-leak-image-info-screen-4-en.png" alt="Anyone can easily delete black rectangles in Word documents" class="fr-fic fr-dii fr-draggable " style="" /></a></p><p>Anyone can easily delete black rectangles in Word documents</p><p></p><p><span style="font-size: 18px"><strong>Mistake 2: Semitransparent filling</strong></span></p><p></p><p></p><p>Another handy tool, this time for iPhone users, is the Markup feature in iOS. Want to send a photo from your phone? You can edit it <a href="https://support.apple.com/en-us/HT206885" target="_blank">directly in an e-mail or message</a>! And the recipient will not be able to undo your edits. Surely, it’s the ideal hassle-free way to hide information on images?</p><p></p><p>Sadly not. The reason is that the pen and highlighter tools draw semitransparent strokes. Sure, if you paint over a piece of text a few times, it might <em>look</em> completely hidden. But by playing around with the brightness, contrast and other image settings, anyone can quickly <a href="https://www.reddit.com/r/ios/comments/e25b7h/here_is_why_you_shouldnt_censor_sensitive_info/" target="_blank">unearth the secret</a>.</p><p></p><p><a href="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130918/how-to-leak-image-info-screen-5-en.png" target="_blank"><img src="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130918/how-to-leak-image-info-screen-5-en.png" alt="Are you sure your hidden text does not show through?" class="fr-fic fr-dii fr-draggable " style="" /></a></p><p>Are you sure your hidden text does not show through?</p><p></p><p></p><p>It is the same story with semitransparent brushes in image editors. All in all, it is better to make sure you’re using 100% opaque tools to conceal data on images.</p><p></p><p><span style="font-size: 18px"><strong>Mistake 3: Invisible secret layer</strong></span></p><p></p><p></p><p>To avoid losing secret information in an image entirely, graphic editors can store it in a separate hidden layer. This is a convenient solution for some images. However, posting a picture with hidden layers online is not a great idea, at least if it is in PNG format.</p><p></p><p>Here is why. When saving an image as a PNG file, the photo editor combines the layers so that they cannot be unglued; however, the information in the hidden layer does not go anywhere — it is right there in the file. And whereas most programs do not display it, in some, for example, the darktable app, simply opening the picture reveals all hidden layers with nothing overlaid.</p><p></p><p><a href="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130929/how-to-leak-image-info-screen-6-en.png" target="_blank"><img src="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130929/how-to-leak-image-info-screen-6-en.png" alt="The same picture opened in different viewers. The lower part of the image was in a hidden layer that showed through in darktable" class="fr-fic fr-dii fr-draggable " style="" /></a></p><p>The same picture opened in different viewers. The lower part of the image was in a hidden layer that showed through in darktable</p><p></p><p><span style="font-size: 18px"><strong>Mistake 4: Reversible filtering</strong></span></p><p></p><p></p><p>Graphic filters that distort the image can also spill the beans. Some displace pixels without deleting them, and it is possible to put them back in place and view the image in its original form.</p><p></p><p>This feature of filters helped police <a href="https://www.minnpost.com/politics-policy/2007/11/you-can-swirl-you-cant-hide/" target="_blank">detain</a> a suspected pedophile from Canada. The criminal posted photos of victims online in which his own face was distorted using a swirling effect. Computer scientists were able to unswirl the images to find out what he looked like. The flip side is that cybercriminals too could use this technique to uncover your secret, after you so diligently tried to swirl it out of view.</p><p></p><p>Of the various image distortion methods, blurring and pixelization, where image info is turned into a jumble of colored squares that cannot be easily rolled back, are considered the most reliable. That said, machine-learning technologies are <a href="http://www.cs.cornell.edu/~shmat/shmat_imgobfuscation.pdf" target="_blank">getting better at recognizing images</a> even if they’re blurred and pixelized.</p><p></p><p>And if you break the image into unduly small pixels, thinking that will keep your secret safe, there is a chance that someone could glimpse what was originally there. The easiest way to do it is by zooming out so that the pixels begin to merge back together. Try playing with the image below to get the idea.</p><p></p><p><a href="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130937/how-to-leak-image-info-screen-7-en.png" target="_blank"><img src="https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130937/how-to-leak-image-info-screen-7-en.png" alt="When using pixelization to hide image info, be sure to play around with the scale to make certain that it does not appear even zoomed out" class="fr-fic fr-dii fr-draggable " style="" /></a></p><p>When using pixelization to hide image info, be sure to play around with the scale to make certain that it does not appear even zoomed out</p><p></p><p><span style="font-size: 18px"><strong>Mistake 5: Not hiding it all</strong></span></p><p></p><p></p><p>Lastly, your secrets can become public knowledge if you leave information that points to them. Carefully painted over your name and profile pic on a screenshot of a social network page, but forgot to hide the address bar? Anyone who wants can enter the address and view your profile. Covered someone’s face with a black rectangle, but left a badge bearing their full name? The subject of the photo will not be difficult to track down.</p><p></p><p>Moreover, a picture isn’t the only thing that can spill secrets; a file’s metadata can as well. For images, that’s primarily information about the time and place they were created, but in some cases, the metadata <a href="https://www.kaspersky.com/blog/exif-privacy/13356/" target="_blank">includes a thumbnail of the original picture</a>, which shows how it looked before retouching.</p><p></p><p>So, before posting a photo anywhere, delete the metadata. There are many mobile apps and programs for desktop computers that will clean your photos of unwanted information in no time at all.</p><p></p><p>Just be aware that malware can masquerade as these utilities, so download the tool only from an official source and avoid granting it too many permissions in the system. And, of course, use a <a href="https://www.kaspersky.com/advert/security-cloud?redef=1&THRU&reseller=gl_kdailyplacehold_acq_ona_smm__onl_b2c_kasperskydaily_wpplaceholder____ksc___" target="_blank">reliable security solution</a> that spots and blocks malicious programs.</p><p></p><p>Good news for Windows users: You can delete metadata from your images without any extra software. Here’s how:</p><p></p><ul> <li data-xf-list-type="ul">Right-click on the file.</li> <li data-xf-list-type="ul">Select <em>Properties</em>.</li> <li data-xf-list-type="ul">In the window that opens, click the <em>Details</em> tab.</li> <li data-xf-list-type="ul">Click <em>Remove Properties and Personal Information</em>.</li> <li data-xf-list-type="ul">Choose whether you want to delete the metadata permanently or create a copy of the file without it.</li> </ul><p><span style="font-size: 18px"><strong>Bonus track: Whoever seeks shall find</strong></span></p><p></p><p></p><p>Anyone desperate to learn your secret will try to extract it even from a well-censored image. For example, if you blotted out each word separately, they might try to guess the text by their number and length, or <a href="https://www.comp.nus.edu.sg/~changec/publications/2008_IH_Residual_Information_Redacted_Image.pdf" target="_blank">recover a small part of the distorted region</a> that can appear around a black rectangle when the image is saved in JPEG format.</p><p></p><p>These are complex and highly unreliable methods, so the casual viewer of your Instagram is unlikely to use them. But if the information in question is extremely sensitive, such subtleties should be kept in mind.</p><p></p><p><span style="font-size: 18px"><strong>How to hide secrets properly</strong></span></p><p></p><p></p><p>To prevent sensitive info in an image from becoming public:</p><p></p><ul> <li data-xf-list-type="ul">Edit pictures in a photo editor and use only redacted images in Office documents.</li> <li data-xf-list-type="ul">Make sure that the tool you use to paint over secret information uses 100% opaque filling.</li> <li data-xf-list-type="ul">If you prefer blurring or pixelization, check thoroughly that the result doesn’t reveal the secret, say, by the shape of the letters.</li> <li data-xf-list-type="ul">Before posting, make sure no other information in the picture could reveal what you want to hide, and thoroughly conceal e-mail addresses, URLs of social network pages, unusual tattoos, name tags, and other such potential identifiers.</li> <li data-xf-list-type="ul">Delete metadata. If for some reason you want to keep it, make a separate, “clean” copy of the file for posting.</li> <li data-xf-list-type="ul">Always think carefully before uploading a picture with sensitive information. Maybe Instagram can survive without a photo of your plane tickets?</li> </ul><p></p><p><a href="https://www.kaspersky.com/blog/how-to-leak-image-info/34875/" target="_blank">Source</a></p></blockquote><p></p>
[QUOTE="Bot, post: 873311, member: 52014"] You have probably had to conceal information in an image on at least one occasion. For example, the tech support guy didn’t need to see your personal data in a screenshot illustrating your issue. Or you wanted to avoid complaints from a passerby in a wedding shot. Or you wanted to show off your [URL='https://www.kaspersky.com/blog/never-post-barcodes-online/12842/']ticket to a long-awaited show[/URL] on Instagram, but do so with the barcode hidden in case someone else fancied going in your place. Bear in mind, however, that blurred — and even cropped! — images can often still reveal the very data you wanted to hide. Here are five ways you could leak your own private information without even suspecting it. [SIZE=5][B]Mistake 1: Editing images in Office apps[/B][/SIZE] This is a classic way to inadvertently share personal or corporate secrets. If the image is for a text document or slide deck, the most convenient way to edit it is directly in the Office application. Just insert the image, crop the part you don’t want to show, save the document, and hand it over to the boss or client with a clear conscience. The problem is that this just changes how the picture appears in the body of the document. The original image remains intact! To see the hidden part, all someone has to do is select the image and then the [I]Crop[/I] tool on the [I]Format[/I] tab. [URL='https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130846/how-to-leak-image-info-screen-1-en.png'][IMG alt="Cropped images in Word ... "]https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130846/how-to-leak-image-info-screen-1-en.png[/IMG][/URL] Cropped images in Word … [URL='https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130855/how-to-leak-image-info-screen-2-en.png'][IMG alt="... are in fact saved intact"]https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130855/how-to-leak-image-info-screen-2-en.png[/IMG][/URL] … are in fact saved intact Good news: You can permanently remove superfluous parts of an image in a document using the [I]Compress Pictures[/I] button on the same [I]Format[/I] tab. Click it and make sure that the [I]Delete cropped areas of pictures[/I] box is selected. [URL='https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130901/how-to-leak-image-info-screen-3-en.png'][IMG alt="Use the Compress Pictures tool to remove sensitive information"]https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130901/how-to-leak-image-info-screen-3-en.png[/IMG][/URL] Use the Compress Pictures tool to remove sensitive information As for black rectangles and various graphic effects, these are of no use at all in Office applications. To see what lies beneath, the recipient can simply remove this superficial artwork. [URL='https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130908/how-to-leak-image-info-screen-4-en.png'][IMG alt="Anyone can easily delete black rectangles in Word documents"]https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130908/how-to-leak-image-info-screen-4-en.png[/IMG][/URL] Anyone can easily delete black rectangles in Word documents [SIZE=5][B]Mistake 2: Semitransparent filling[/B][/SIZE] Another handy tool, this time for iPhone users, is the Markup feature in iOS. Want to send a photo from your phone? You can edit it [URL='https://support.apple.com/en-us/HT206885']directly in an e-mail or message[/URL]! And the recipient will not be able to undo your edits. Surely, it’s the ideal hassle-free way to hide information on images? Sadly not. The reason is that the pen and highlighter tools draw semitransparent strokes. Sure, if you paint over a piece of text a few times, it might [I]look[/I] completely hidden. But by playing around with the brightness, contrast and other image settings, anyone can quickly [URL='https://www.reddit.com/r/ios/comments/e25b7h/here_is_why_you_shouldnt_censor_sensitive_info/']unearth the secret[/URL]. [URL='https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130918/how-to-leak-image-info-screen-5-en.png'][IMG alt="Are you sure your hidden text does not show through?"]https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130918/how-to-leak-image-info-screen-5-en.png[/IMG][/URL] Are you sure your hidden text does not show through? It is the same story with semitransparent brushes in image editors. All in all, it is better to make sure you’re using 100% opaque tools to conceal data on images. [SIZE=5][B]Mistake 3: Invisible secret layer[/B][/SIZE] To avoid losing secret information in an image entirely, graphic editors can store it in a separate hidden layer. This is a convenient solution for some images. However, posting a picture with hidden layers online is not a great idea, at least if it is in PNG format. Here is why. When saving an image as a PNG file, the photo editor combines the layers so that they cannot be unglued; however, the information in the hidden layer does not go anywhere — it is right there in the file. And whereas most programs do not display it, in some, for example, the darktable app, simply opening the picture reveals all hidden layers with nothing overlaid. [URL='https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130929/how-to-leak-image-info-screen-6-en.png'][IMG alt="The same picture opened in different viewers. The lower part of the image was in a hidden layer that showed through in darktable"]https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130929/how-to-leak-image-info-screen-6-en.png[/IMG][/URL] The same picture opened in different viewers. The lower part of the image was in a hidden layer that showed through in darktable [SIZE=5][B]Mistake 4: Reversible filtering[/B][/SIZE] Graphic filters that distort the image can also spill the beans. Some displace pixels without deleting them, and it is possible to put them back in place and view the image in its original form. This feature of filters helped police [URL='https://www.minnpost.com/politics-policy/2007/11/you-can-swirl-you-cant-hide/']detain[/URL] a suspected pedophile from Canada. The criminal posted photos of victims online in which his own face was distorted using a swirling effect. Computer scientists were able to unswirl the images to find out what he looked like. The flip side is that cybercriminals too could use this technique to uncover your secret, after you so diligently tried to swirl it out of view. Of the various image distortion methods, blurring and pixelization, where image info is turned into a jumble of colored squares that cannot be easily rolled back, are considered the most reliable. That said, machine-learning technologies are [URL='http://www.cs.cornell.edu/~shmat/shmat_imgobfuscation.pdf']getting better at recognizing images[/URL] even if they’re blurred and pixelized. And if you break the image into unduly small pixels, thinking that will keep your secret safe, there is a chance that someone could glimpse what was originally there. The easiest way to do it is by zooming out so that the pixels begin to merge back together. Try playing with the image below to get the idea. [URL='https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130937/how-to-leak-image-info-screen-7-en.png'][IMG alt="When using pixelization to hide image info, be sure to play around with the scale to make certain that it does not appear even zoomed out"]https://media.kasperskydaily.com/wp-content/uploads/sites/92/2020/04/13130937/how-to-leak-image-info-screen-7-en.png[/IMG][/URL] When using pixelization to hide image info, be sure to play around with the scale to make certain that it does not appear even zoomed out [SIZE=5][B]Mistake 5: Not hiding it all[/B][/SIZE] Lastly, your secrets can become public knowledge if you leave information that points to them. Carefully painted over your name and profile pic on a screenshot of a social network page, but forgot to hide the address bar? Anyone who wants can enter the address and view your profile. Covered someone’s face with a black rectangle, but left a badge bearing their full name? The subject of the photo will not be difficult to track down. Moreover, a picture isn’t the only thing that can spill secrets; a file’s metadata can as well. For images, that’s primarily information about the time and place they were created, but in some cases, the metadata [URL='https://www.kaspersky.com/blog/exif-privacy/13356/']includes a thumbnail of the original picture[/URL], which shows how it looked before retouching. So, before posting a photo anywhere, delete the metadata. There are many mobile apps and programs for desktop computers that will clean your photos of unwanted information in no time at all. Just be aware that malware can masquerade as these utilities, so download the tool only from an official source and avoid granting it too many permissions in the system. And, of course, use a [URL='https://www.kaspersky.com/advert/security-cloud?redef=1&THRU&reseller=gl_kdailyplacehold_acq_ona_smm__onl_b2c_kasperskydaily_wpplaceholder____ksc___']reliable security solution[/URL] that spots and blocks malicious programs. Good news for Windows users: You can delete metadata from your images without any extra software. Here’s how: [LIST] [*]Right-click on the file. [*]Select [I]Properties[/I]. [*]In the window that opens, click the [I]Details[/I] tab. [*]Click [I]Remove Properties and Personal Information[/I]. [*]Choose whether you want to delete the metadata permanently or create a copy of the file without it. [/LIST] [SIZE=5][B]Bonus track: Whoever seeks shall find[/B][/SIZE] Anyone desperate to learn your secret will try to extract it even from a well-censored image. For example, if you blotted out each word separately, they might try to guess the text by their number and length, or [URL='https://www.comp.nus.edu.sg/~changec/publications/2008_IH_Residual_Information_Redacted_Image.pdf']recover a small part of the distorted region[/URL] that can appear around a black rectangle when the image is saved in JPEG format. These are complex and highly unreliable methods, so the casual viewer of your Instagram is unlikely to use them. But if the information in question is extremely sensitive, such subtleties should be kept in mind. [SIZE=5][B]How to hide secrets properly[/B][/SIZE] To prevent sensitive info in an image from becoming public: [LIST] [*]Edit pictures in a photo editor and use only redacted images in Office documents. [*]Make sure that the tool you use to paint over secret information uses 100% opaque filling. [*]If you prefer blurring or pixelization, check thoroughly that the result doesn’t reveal the secret, say, by the shape of the letters. [*]Before posting, make sure no other information in the picture could reveal what you want to hide, and thoroughly conceal e-mail addresses, URLs of social network pages, unusual tattoos, name tags, and other such potential identifiers. [*]Delete metadata. If for some reason you want to keep it, make a separate, “clean” copy of the file for posting. [*]Always think carefully before uploading a picture with sensitive information. Maybe Instagram can survive without a photo of your plane tickets? [/LIST] [url="https://www.kaspersky.com/blog/how-to-leak-image-info/34875/"]Source[/url] [/QUOTE]
Insert quotes…
Verification
Post reply
Top
