Archives For Linux Forensics
While doing some research on Linux forensics, I stumbled upon an excellent paper written by Gregorio Narvaez. The paper is titled, “Taking Advantage of EXT3 Journaling File System in a Forensic Investigation”. Those of you who have performed linux forensics before know that the EXT3 filesystem dealt our field a serious blow with regard to file recovery. When a file was deleted in EXT2, the pointer to the file inode within the directory entry was removed. This severed the link between the file name layer and the meta-data layer, but all of the block pointers within the inode were maintained. Thus, we could fully recover deleted files, but could not tie them back to their original filenames. When EXT3 emerged, things took a nastier turn. Now, instead of removing the pointer to the inode when a file is deleted in EXT3, all of the block pointers within the inode are deleted. This makes data recovery in EXT3 much, much more difficult. Luckily, the developers threw us a bone: the EXT3 journal keeps copies of recently modified inodes, including complete copies of previously deleted block pointers!