Linux Memory Grabber
A script for dumping Linux memory and creating Volatility(TM)ABOUT THE TOOL
To analyze Linux memory, you first need to be able to capture Linux memory. Joe Sylve's Linux Memory Extractor (LiME) is excellent for this, but you need to have a LiME module compiled for the kernel of the system where you want to grab RAM. Volatility(TM) is great at analyzing Linux memory images. But it needs a profile that matches the system where the memory was captured. Building a profile means compiling a C program on the appropriate system and using dwarfdump to get the addresses of important kernel data structures. You also need a copy of the System.map file from the /boot directory. Now if you happen to have a duplicate of your target system, you can build LiME and compile the Volatility(TM) profile on the clone and use them to capture and analyze memory from your target. But there are many situations where a duplicate of your target system is not available. So you may have to compile LiME and build your Volatility(TM) profile on your target machine. And this is not for the faint of heart. There are a number of steps, and some fairly low-level Linux commands involved. My goal was to create a package that could be installed (by an expert) on a thumb drive and distributed to agents in the field. The user of the thumb drive should be able to plug the thumb drive in, run a single command, and successfully acquire a memory image of the target machine and a working Volatility(TM) profile. The result is my lmg (Linux Memory Grabber) script.ON FORENSIC PURITY
If you're a stickler for forensic purity, this is probably not the tool for you. Let's discuss some of the ways in which my tool interacts with the target system:Removable Media -- The tool is designed to be run from a portable USB
device such as a thumb drive. You are going to be plugging a writable device into your target system, where it could potentially be targeted by malicious users or malware on the system. The act of plugging the device into the system is going to change the state of the machine (e.g., create log entries, mtab entries, etc). If the device is not auto-mounted by the operating system, the user must manually mount the device via a root shell.Compilation -- lmg builds a LiME kernel module for the system.
Creating a Volatility(TM) profile also involves compiling code on the target machine. So gcc will be executed, header files read, libraries linked, etc. lmg tries to minimize impact on the file system of the target machine by setting TMPDIR to a directory on the USB device lmg runs from. This means that intermediate files created by the compiler will be written to the thumb drive rather than the local file system of the target machine.Dependencies -- In order to compile kernel code on Linux, the target
machine needs a working development environment with gcc, make, etc and all of the appropriate include files and shared libraries. And in particular, the kernel header files need to be present on the local machine. These dependencies may not exist on the target system. In this case, the user is faced with the choice of installing the appropriate dependencies (if possible) or being unable to acquire memory from the target.Malware -- lmg uses /bin/bash, gcc, and a host of other programs from
the target machine. If the system has been compromised, the applications lmg uses may not be trustworthy. A more complete solution would be to create a secure execution environment for lmg on the portable USB device, but was beyond the scope of this initial proof of concept.Memory -- All of the commands being run will cause the memory of the
target system to change. The act of capturing RAM will always create artifacts, but in this case there is extensive compilation, file system access, etc in addition to running a RAM dumper. All of that being said, lmg is a very convenient tool for allowing less-skilled agents to capture useful memory analysis data from target systems. Note that lmg will look for an already existing LiME module on the USB device that matches the kernel version and processor architecture of the target machine. If found, lmg will not bother to recompile. Similarly, you may choose to not have lmg create the Volatility(TM) profile for the target in order to minimize the impact on the target system.USING LMG
First, prepare a thumb drive according to the instructions in the INSTALL document provided with lmg. When you wish to acquire RAM, plug the thumb drive into your target system. On most Linux systems, new USB devices will get automatically mounted under /media. Let's assume yours ends up under /media/LMG. Now, as root, run "/media/LMG/lmg". This is interactive mode and the user will be prompted for confirmation before lmg builds a LiME module for the system and/or creates a Volatility(TM) profile. If you don't want to be prompted, use "/media/LMG/lmg -y". Everything else is automated. After the script runs, you will have a new directory on the thumb drive named ".../capture/<hostname>-YYYY-MM-DD_hh.mm.ss" In this directory you will find: <hostname>-YYYY-MM-DD_hh.mm.ss-memory.lime -- the RAM capture <hostname>-YYYY-MM-DD_hh.mm.ss-profile.zip -- Volatility(TM) profile <hostname>-YYYY-MM-DD_hh.mm.ss-bash -- copy of target's /bin/bash The copy of /bin/bash is helpful for determining the address of the shell history data structure in the memory of bash processes in the memory capture. See http://code.google.com/p/volatility/wiki/LinuxCommandReference23#linux_bash for further details on how to use this executable.HOW TO USE
Here is an example of using the lmg tool, which includes using Volatility(TM) directly off the thumb drive to analyze the captured image. On my test machine, the thumb drive was at /dev/sdb and it was not auto-mounted by my operating system. So I did everything manually.1) Getting root and mounting the thumb drive
caribou$ sudo -s [sudo] password for hal: caribou# mkdir -p /mnt/usb caribou# mount /dev/sdb1 /mnt/usb2) Running lmg
caribou# /mnt/usb/lmg -y make -C /lib/modules/3.2.0-41-generic/build M=/mnt/usb/lime/src modules make[1]: Entering directory `/usr/src/linux-headers-3.2.0-41-generic' CC [M] /mnt/usb/lime/src/tcp.o CC [M] /mnt/usb/lime/src/disk.o CC [M] /mnt/usb/lime/src/main.o LD [M] /mnt/usb/lime/src/lime.o Building modules, stage 2. MODPOST 1 modules CC /mnt/usb/lime/src/lime.mod.o LD [M] /mnt/usb/lime/src/lime.ko make[1]: Leaving directory `/usr/src/linux-headers-3.2.0-41-generic' strip --strip-unneeded lime.ko mv lime.ko lime-3.2.0-41-generic-x86_64.ko make tidy make[1]: Entering directory `/mnt/usb/lime/src' rm -f *.o *.mod.c Module.symvers Module.markers modules.order \.*.o.cmd \.*.ko.cmd \.*.o.d rm -rf \.tmp_versions make[1]: Leaving directory `/mnt/usb/lime/src' Dumping memory in "lime" format to /mnt/usb/capture/caribou-2014-03-29_12.06.01 This could take a while...Done! Cleaning up...Done! Grabbing a copy of /bin/bash...Done! make -C //lib/modules/3.2.0-41-generic/build CONFIG_DEBUG_INFO=y M=/mnt/usb/volatility-2.3.1/tools/linux modules make[1]: Entering directory `/usr/src/linux-headers-3.2.0-41-generic' CC [M] /mnt/usb/volatility-2.3.1/tools/linux/module.o Building modules, stage 2. MODPOST 1 modules CC /mnt/usb/volatility-2.3.1/tools/linux/module.mod.o LD [M] /mnt/usb/volatility-2.3.1/tools/linux/module.ko make[1]: Leaving directory `/usr/src/linux-headers-3.2.0-41-generic' dwarfdump -di module.ko > module.dwarf make -C //lib/modules/3.2.0-41-generic/build M=/mnt/usb/volatility-2.3.1/tools/linux clean make[1]: Entering directory `/usr/src/linux-headers-3.2.0-41-generic' CLEAN /mnt/usb/volatility-2.3.1/tools/linux/.tmp_versions CLEAN /mnt/usb/volatility-2.3.1/tools/linux/Module.symvers make[1]: Leaving directory `/usr/src/linux-headers-3.2.0-41-generic' adding: module.dwarf (deflated 90%) adding: boot/System.map-3.2.0-41-generic (deflated 79%) caribou# ls /mnt/usb/capture/caribou-2014-03-29_12.06.01/ caribou-2014-03-29_12.06.01-bash caribou-2014-03-29_12.06.01-memory.lime caribou-2014-03-29_12.06.01-profile.zip3) Check for the new profile
caribou# export VOLATILITY_PLUGINS=/mnt/usb/capture/caribou-2014-03-29_12.06.01 caribou# /mnt/usb/volatility-2.3.1/vol.py --info | grep Linux Volatility Foundation Volatility Framework 2.3.1 linux_banner - Prints the Linux banner information linux_yarascan - A shell in the Linux memory image Linuxcaribou-2014-03-29_12_06_01-profilex64 - A Profile for Linux caribou-2014-03-29_12.06.01-profile x644) Choose the new profile and memory capture, run linux_pslist to test
caribou# export VOLATILITY_PROFILE=Linuxcaribou-2014-03-29_12_06_01-profilex64 caribou# export VOLATILITY_LOCATION=file:///mnt/usb/capture/caribou-2014-03-29_12.06.01/caribou-2014-03-29_12.06.01-memory.lime caribou# /mnt/usb/volatility-2.3.1/vol.py linux_pslist Volatility Foundation Volatility Framework 2.3.1 Offset Name Pid Uid Gid DTB Start Time ------------------ -------------------- --------------- --------------- ------ ------------------ ---------- 0xffff88022e0e8000 init 1 0 0 0x0000000228f73000 2014-03-29 14:10:23 UTC+0000 0xffff88022e0e9700 kthreadd 2 0 0 ------------------ 2014-03-29 14:10:23 UTC+0000 0xffff88022e0eae00 ksoftirqd/0 3 0 0 ------------------ 2014-03-29 14:10:23 UTC+0000 [... more output not shown ...]5) Use the captured copy of /bin/bash to dump shell history with linux_bash
caribou# gdb /mnt/usb/capture/caribou-2014-03-29_12.06.01/caribou-2014-03-29_12.06.01-bash GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2.1) 7.4-2012.04 Copyright (C) 2012 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-linux-gnu". For bug reporting instructions, please see: <http://bugs.launchpad.net/gdb-linaro/>... Reading symbols from /mnt/usb/capture/caribou-2014-03-29_12.06.01/caribou-2014-03-29_12.06.01-bash...(no debugging symbols found)...done. (gdb) disass history_list Dump of assembler code for function history_list: 0x00000000004a53f0 <+0>: mov 0x2490c9(%rip),%rax # 0x6ee4c0 0x00000000004a53f7 <+7>: retq End of assembler dump. (gdb) quit caribou# vol.py linux_bash -H 0x6ee4c0 -P Volatility Foundation Volatility Framework 2.3.1 Pid Name Command Time Command -------- -------------------- ------------------------------ ------- 2604 bash 2014-03-29 14:11:17 UTC+0000 cat workshop-outline 2604 bash 2014-03-29 14:11:17 UTC+0000 sigfind -b 4096 006D6C6F6361 /dev/mapper/RD-var [... more output not shown ...]
Download tool : https://goo.gl/1YfJPt
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