Hiding files inside jpg images

[Max_87]

A USA Today story claimed that al-Qaeda operatives were sending out encrypted messages by hiding them inside digital photographs [jpg files] on eBay.

While the claim was never proved, it is very easy to hide [or embed] any other file[s] inside a JPEG image. You can place video clips, pdf, mp3, Office documents, zipped files, webpage or any other file format inside a JPEG image.

And when a suspecting user [read CIA, FBI] tries to open that jpeg file [with concealed information] in either a photo editing software or as a thumbnail inside Windows Explorer, it would be tough to make out if this camouflaged jpg file is different from any standard jpg image.

Let's say you want to hide a confidential PDF document from the tax investigation officers. What you can do is convert that file into a regular jpg image so even if anyone double-clicks this file, all he will see is a preview of the image and nothing else. And when you want to work on the actual PDF, just rename the extension from jpg to pdf.

Here's the full trick:

Step 1: You will need two files - the file you want to hide and one jpg image - it can be of any size or dimensions. [If you want to hide multiple files in one jpeg image, just zip them into one file]

Step 2: Copy the above two files to the C: folder and open the command prompt window.

Step 3: Move to the c: root by typing cd \ [if the files are in another folder, you'll have to change the prompt to that folder]

Step 4: The most important step - type the following command:

copy /b myimage.jpg + filetohide.pdf my_new_image.jpg

To recover the original PDF file, just rename my_new_image.jpg to filename.pdf.

Here we illustrated with an pdf file as that works with simple renaming. If you want to apply this technique to other file formats like XLS, DOC, PPT, AVI, WMV, WAV, SWF, etc, you may have to first compress them in RAR format before executing the copy /b DOS command.

To restore the original file, rename the .jpg file to .rar and extract it using 7-zip or Winrar.

That's it - No advanced Steganography tricks involved here. Just remember to write the correct syntax of the copy command:

copy /b sourceimage.jpg + filetohide.ext targetimage.jpg

http://labnol.blogspot.com/2006/10/h...uments-or.html

Interesting I never know we could hide files this way

[Chai]

So al-Qaeda hide their secret documents, while you guys will be hiding pr0n at home?

[Max_87]

pr0n? no need hide lah, ask Dashken

[Dashken]

Yalor... just send your HDD over...

[khelben]

Hehe i learned how to do this a few years back at 4chan, but i was never bothered to use it

[Olle P]

Well, there is at least one telltale sign of these modified images: File size. You can't add data without adding to the file size.
It becomes less suspicious if the added file is substantially smaller than the original image file.

Now I tried it. Merging two files (jpg + pdf) into a working image is no sweat, but I can't re-open it as a pdf!

Cheers
Olle

[zy]

i dunno how possible is this trick
but i will always think you will curropt the file .. hmm

anyone up for the ultimate test ?

[ChampionLLY]

didnt know there's such a trick...
if got private stuff, i'll juz rename it to sth like system32.dll or 0001bd.tmp & hide it among all the system files

lol...

[Adrian Wong]

Hehe.. This is a pretty old technique.

If they want, they can actually embed the data within the picture itself. Or combine two pictures together, like what people used to do to hide porn pictures.

You know, when you open it, it's an ordinary picture of your and your family (for example). But when you select it in IE, another picture appears.