一种基于闪存物理镜像的FAT文件系统重组方法  

A Method for Reconstructing the FAT File System from Flash Memory

作　　者：张丽[1,2] 谭毓安[1,3] 郑军[1,3] 马忠梅[1] 王文明[1] 李元章[1] 

机构地区：[1]北京理工大学计算机学院,北京100081 [2]南阳师范学院计算机与信息技术学院,河南南阳473061 [3]北京理工大学北京市海量信息处理与云计算应用工程技术中心,北京100081

出　　处：《电子学报》2013年第8期1487-1493,共7页Acta Electronica Sinica

基　　金：国家863高技术研究发展计划(No.2013AA01A212)

摘　　要：文件系统重组是闪存设备取证研究进行数据恢复的主要手段.传统的文件系统重组方法需要同时获取闪存设备在同一时刻的逻辑镜像和物理镜像,该条件在取证实践中常常难以满足,故提出一种仅依赖闪存物理镜像重组文件分配表(FAT)文件系统的方法.在引入统计分析法从物理镜像中提取逻辑地址字段和页状态字段的基础上,给出利用最新页状态值准确重组闪存设备最新FAT文件系统镜像的算法.最后以MTK6229闪存设备物理镜像的FAT文件系统重组过程为例,验证上述重组算法及相关方法是正确的.The file system reconstruction is an effective way of recovering the forensic data from Flash memory.However,the traditional reconstruction methods need a precondition that is there are both the logical image and the physical image of flash memory at the same time and that is usually not satisfied in practice.In this paper,we propose a method for reconstructing the File Allocation Table（FAT） file system of Flash device when only a physical image of Flash memory is acquired.After introducing the statistical methods to identify the logical address bytes and the page state byte from the physical image,we propose the new algorithm to reconstruct the newest FAT file system which is based on the newest value of the page state.At last,take the special flash devices with MTK6229 controllers as examples,we expound the methods related to reconstructing the FAT file system and verify the reconstruction algorithm.

关 键 词：数字取证 闪存 物理镜像 文件系统重组 空闲区 

分 类 号：TP309.3[自动化与计算机技术—计算机系统结构]