7 ms·

Their answer is to "color over it", but BE CAREFUL if you do that. I'm sure that some of us remember the US government document(s) in the late 90s/early 2000s t

by nnnnni 12y ago

Their answer is to "color over it", but BE CAREFUL if you do that. I'm sure that some of us remember the US government document(s) in the late 90s/early 2000s that were released in redacted form, but the person didn't realize/understand that people with the Acrobat editor program could remove the black bars.

currysausage 12y ago
Also great: HTML pages with sensitive passages using #000 for background and foreground. You just need to select and copy to Notepad - voila. I think I once saw that on the site of a home security company, citing an email from customers who thanked them for burglarproofing their home in XX XXXXXXXX Street. Quite ironic.
MichaelApproved 12y ago
You don't have to go all the way back to the early 2000s to find poorly redacted federal documents. Rachel Maddow had a great segment on botched redactions, like removing the black lines from a PDF. The best solution was to actually cut out the parts of the page you don't want seen and then scan in the result. All other methods are prone to mistakes. Edit: corrected link to segment http://www.msnbc.com/rachel-maddow-show/watch/redaction-rules-how-best-to-keep-the-secrets-258076739607 http://www.msnbc.com/rachel-maddow-show/watch/redaction-rule...
- Houshalter 12y ago
  Would a screenshot work?
  - freehunter 12y ago
    I've always drawn over sensitive parts in Paint or something, then taken a screenshot of it. It makes sure that everything is compressed to a single layer and can't be undone.
    - im3w1l 12y ago
      Just be sure to get all of it. It's pretty common that people leave a few pixels. How not to do it: https://imgur.com/ZaCIY5P https://imgur.com/ZaCIY5P
      - dheera 12y ago
        Leave generous margins. JPEGs can have compression artifacts that leak information outside the boundaries of the object.
        Houshalter 12y ago
        It shouldn't matter if the original image (the screenshot) didn't contain any information to leak.
  - tormeh 12y ago
    Exactly my thought. A BMP is too simple to go wrong. There's so many pitfalls with digital files, because they can have much more information than the viewer will show you in an obvious manner or at all. Not only layers, but metadata (EXIF) and whatnot.
- dheera 12y ago
  Along the same lines, I remember an MIT Mystery Hunt puzzle once where there were hidden clues in a PostScript document. If you didn't think to look at the PostScript source you probably had no hope of solving it.
shinigami 12y ago
Also, image formats like JPEG have a thumbnail stored in them, which may not be updated when you edit the image.
- robin_reala 12y ago
  Do they? First I’ve heard of that…
  - akadruid1 12y ago
    The thumbnail is part of the EXIF metadata. It's reasonably well-known now, but it was not always the case... http://graphicssoft.about.com/b/2003/07/26/techtvs-cat-schwartz-exposed-is-photoshop-to-blame.htm http://graphicssoft.about.com/b/2003/07/26/techtvs-cat-schwa...
    - robin_reala 12y ago
      Huh, interesting. Thanks!
  - philjohn 12y ago
    A few years ago a TV presenter got caught out by this, she posted a cropped photo of herself online, but the original, uncropped version could be recovered from the file which showed her topless.
  - bluedino 12y ago
    There was a trend for a while of people posting images to imgur that had a totally different thumbnail. A rickroll of sorts.
  - dheera 12y ago
    You can use 'exiftool' on Linux to manipulate the EXIF data, get rid of the thumbnail, or set it to whatever you want. Imagemagick's 'convert' command also has a '-strip' option that will get rid of all EXIF data including any thumbnails.
  - Natsu 12y ago
danielweber 12y ago
There is also "Leaking Sensitive Information in Complex Document Files--and How to Prevent It" from IEEE Security & Privacy earlier this year. All copies might be behind paywalls, however.
matchu 12y ago
For a fun variant of this problem, see the 2008 Underhanded C Contest: http://underhanded.xcott.com/?page_id=17 http://underhanded.xcott.com/?page_id=17

by nnnnni 12y ago

currysausage 12y ago

Also great: HTML pages with sensitive passages using #000 for background and foreground. You just need to select and copy to Notepad - voila. I think I once saw that on the site of a home security company, citing an email from customers who thanked them for burglarproofing their home in XX XXXXXXXX Street. Quite ironic.

MichaelApproved 12y ago

You don't have to go all the way back to the early 2000s to find poorly redacted federal documents. Rachel Maddow had a great segment on botched redactions, like removing the black lines from a PDF. The best solution was to actually cut out the parts of the page you don't want seen and then scan in the result. All other methods are prone to mistakes. Edit: corrected link to segment http://www.msnbc.com/rachel-maddow-show/watch/redaction-rules-how-best-to-keep-the-secrets-258076739607 http://www.msnbc.com/rachel-maddow-show/watch/redaction-rule...

Houshalter 12y ago
Would a screenshot work?
- freehunter 12y ago
  I've always drawn over sensitive parts in Paint or something, then taken a screenshot of it. It makes sure that everything is compressed to a single layer and can't be undone.
  - im3w1l 12y ago
    Just be sure to get all of it. It's pretty common that people leave a few pixels. How not to do it: https://imgur.com/ZaCIY5P https://imgur.com/ZaCIY5P
    - dheera 12y ago
      Leave generous margins. JPEGs can have compression artifacts that leak information outside the boundaries of the object.
      - Houshalter 12y ago
        It shouldn't matter if the original image (the screenshot) didn't contain any information to leak.
- tormeh 12y ago
  Exactly my thought. A BMP is too simple to go wrong. There's so many pitfalls with digital files, because they can have much more information than the viewer will show you in an obvious manner or at all. Not only layers, but metadata (EXIF) and whatnot.
dheera 12y ago
Along the same lines, I remember an MIT Mystery Hunt puzzle once where there were hidden clues in a PostScript document. If you didn't think to look at the PostScript source you probably had no hope of solving it.

shinigami 12y ago

Also, image formats like JPEG have a thumbnail stored in them, which may not be updated when you edit the image.

robin_reala 12y ago
Do they? First I’ve heard of that…
- akadruid1 12y ago
  The thumbnail is part of the EXIF metadata. It's reasonably well-known now, but it was not always the case... http://graphicssoft.about.com/b/2003/07/26/techtvs-cat-schwartz-exposed-is-photoshop-to-blame.htm http://graphicssoft.about.com/b/2003/07/26/techtvs-cat-schwa...
  - robin_reala 12y ago
    Huh, interesting. Thanks!
- philjohn 12y ago
  A few years ago a TV presenter got caught out by this, she posted a cropped photo of herself online, but the original, uncropped version could be recovered from the file which showed her topless.
- bluedino 12y ago
  There was a trend for a while of people posting images to imgur that had a totally different thumbnail. A rickroll of sorts.
- dheera 12y ago
  You can use 'exiftool' on Linux to manipulate the EXIF data, get rid of the thumbnail, or set it to whatever you want. Imagemagick's 'convert' command also has a '-strip' option that will get rid of all EXIF data including any thumbnails.
- Natsu 12y ago

danielweber 12y ago

There is also "Leaking Sensitive Information in Complex Document Files--and How to Prevent It" from IEEE Security & Privacy earlier this year. All copies might be behind paywalls, however.

matchu 12y ago

For a fun variant of this problem, see the 2008 Underhanded C Contest: http://underhanded.xcott.com/?page_id=17 http://underhanded.xcott.com/?page_id=17