In part 2, we are going to take a closed look at the image in object 3.
First we dump the stream and look at the beginning and end:
FF D8 is the Start Of Image Marker of a JPEG image.
FF D9 is the Eod Of Image Marked of a JPEG image.
It's likely that we are indeed dealing with a JPEG image, and not something else.
Next I check if I can find strings inside the JPEG image:
With my maldoc YARA rules (maldoc.yara found in the oledump.py ZIP package) I can search for shellcode:
The second line will perform the same scan, but with decoders to see if the shellcode is encoded with simple encoding techniques (XOR 1 byte, ADD 1 byte and ROL 1 byte).
There is no output from these commands, the YARA rules don't trigger: this means we can't find shellcode inside the image. This does not necessarily mean there is no shellcode, but that we can't find any...
In part 3, we'll take a deeper look...
Sep 4th 2017
2 years ago