LAS VEGAS--In a presentation at the Black Hat conference here Tuesday, Neal Krawetz of Hacker Factor showed how basic manipulations to images can be revealed through digital analysis.
After presenting on the specific techniques he used, Krawetz launched into what he called the case of "Dr. Z," who happens to be Ayman al-Zawahiri, the No. 2 man in al-Qaida.
Using a photo that originally appeared on December 20, 2006, in USA Today, al-Zawahiri appears to be seated before a large banner with a desk underneath. On the desk, in the photo, is a tiny cannon. Yet in the text, al-Zawahiri is described as sitting with "a rifle behind his shoulder that was leaning against a plain brown backdrop."
Using the techniques demonstrated earlier in the talk, Krawetz deconstructed the image to show a halo around al-Zawahiri that suggests that he was likely sitting in front of a monochromatic screen. Even the letters on the banner had been altered. Further, the overall image had been cropped from the original.
Krawetz showed another image of al-Zawahiri from July 27, 2006, showing him seated in what appears to be a television studio. Krawetz said many people who saw this video were outraged that he could sitting in a television studio somewhere, yet the U.S. government couldn't find him.
Image analysis suggests that the studio and the various pictures positioned in the studio around him were added later. Again, a halo around al-Zawahiri suggests that he was shot in front of a monochromatic screen and pasted into a new background.
The studio background behind al-Zawahiri includes five different elements placed within the shot: The picture of Mohammad Alef is taken from a video of a wedding ceremony. The picture of the Twin Towers and the picture of Mohammad Atta are both taken from the 911 Commission report. Meanwhile, the studio itself appears created; the lighting suggests that the wall is an unlikely 1 foot behind al-Zawahiri, for example.
Krawetz found an image from the SITE Institute, an organization that tracks terrorism worldwide. (SITE stands for Search for International Terrorist Entities.) The image was intercepted before it was released by al-Qaida.
In the SITE video, al-Zawahiri appears before a blackened backdrop. In the upper-right corner, there appears to be the edge of a wall or screen. By adjusting the contrast, Krawetz could see that the wall behind al-Zawahiri is a draped backdrop. Krawetz didn't show the final al-Qaida image, but it likely included a composite of images designed to disguise his true location and press a specific message. As was the case in the final image Krawetz showed.
An image of Azzam al-Almriki, another member of al-Qaida, showed the young man seated in an office with a computer and a stack of books. Image analysis shows that the books were added. What an odd detail, yet it must be there to convey added meaning.
Throughout his demonstration, Krawetz did not speculate on the reasons behind al-Qaida's image manipulation. His interest is only that the images were manipulated and that the specific changes could be revealed.