Hi, While creating a stripped down version of xloadimage, I have discovered three buffer overflows in xloadimage when handling the image title name. Unlike most of the supported image formats in xloadimage, the NIFF image format can store a title name of arbitrary length as part of the image file. When xloadimage is processing a loaded image, it is creating a new Image object and then writing the processed image to it. At that point, it will also copy the title from the old image to the newly created image. The 'zoom', 'reduce', and 'rotate' functions are using a fixed length buffer to construct the new title name when an image processing is done. Since the title name in a NIFF format is of varying length, and there are insufficient buffer size validations, the buffer can be overflowed. A malicious user can construct a NIFF file that when viewed and processed (with either zoom, reduce or rotate) by xloadimage, will cause the program to overwrite the return address and execute arbitrary code. Proof of concept for the 'zoom' image processing bug, tested on a x86 computer running Gentoo Linux: emerge xloadimage xloadimage -zoom 20 small.niff (small.niff is attached) This will execute '/bin/sh'. Note: some systems may have the (/proc/sys/kernel/)randomize_va_space option enabled, which will cause the program to crash instead of executing /bin/sh in most cases. Using a larger NIFF file (large.niff.gz [800KB unzipped]), it is possible to execute arbitrary code even when the random address space option is enabled (with about 33% success rate). The 'reduce' and 'rotate' bugs are similar, but require a slightly different NIFF file and different ( processing options. The bugs are in : zoom.c, zoom() writes an arbitrarily large buffer into a 8192 bytes sized buffer buf[]. reduce.c, reduce() writes an arbitrarily large buffer into a 8192 bytes sized buffer buf[]. rotate.c, rotate() writes an arbitrarily large buffer into a 8192 bytes sized buffer buf[]. The bugs discussed above exist in the latest xloadimage package that Gentoo provides (xloadimage.4.1-r3), and the latest xloadimage source package from debian I could find (xloadimage_4.1-14.2). I haven't tested xloadimage packages from other sources. I emailed jimf@xxxxxxxxxxxxxx (the contact information on the help page) more than two weeks ago, but since I've recieved no reply, I am announcing it here. Thanks, Ariel Berkman.
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