Malware Analysis and Defeating using Virtual Machines
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Transcript of Malware Analysis and Defeating using Virtual Machines
1
THE DETECTION AND DEFEATING OF MALWARE IN POPULAR VIRTUAL MACHINES
2Objective
To study the VM detection techniques in popular Virtual machines.
Develop strategy to counter the detection. Prevent analysis aware malwares from
detecting VM.
3Plan of Action Introduction VM detection techniques Detection techniques in VMware, VirtualBox and
VirtualPC. Related Work Prevent Analysis aware malwares from detecting VM. VMDetectGuard – Tool to mask VM detection :
Windows Optimization of VMDetectGuard Results
4
Introduction
5Malware Malware: It is a collective term for
any malicious software which enters the system without the authorization of the user of the system.
Anti-virus/anti-malware products do not guarantee complete protection.
6Present Scenario
Security researchers use malware analysis tools to build defenses against the unknown malware forms.
They then build patches for the newly discovered vulnerabilities and exploits.
Virtualization has emerged as a very promising technology.
Malware analyst use Virtual Machine Environment (VME), debuggers and sandboxes in their analysis work.
7VirtualizationA software based representation of a
computer that executes programs in the same way as a real computer.
Examples, VMware, Virtual PC, VirtualBox.Advantages
Reduced capital and operational costs through more efficient use of hardware resources.
Simplifies maintenance . Improves scalability and deployment agility. Improves reliability.
8Benefits of Virtualization to Security Researchers
Researchers can intrepidly execute potential malware samples without having their systems affected.
If a malware destabilizes the OS, analyst just needs to load in a fresh image on a VM.
Reduces time and cost. Increases productivity.
9Analysis Awareness Functionality
Malware developers have added a new functionality to malware.
Detect the presence of analysis tools such as VMs, debuggers and sandboxes.
Hide their malicious behavior on detection. Analysis Aware / Split Personality malware.
10Related Work
Carpenter (Carpenter et al., 2007) proposes two mitigation techniques.
They aim at tricking the malware by1. Changing the configuration settings of the .vmx
file present on the host system and,2. Altering the magic value to break the guest-host
communication channel.
11Drawbacks of the First
Approach The configuration options break the
communication channel between guest and host not just for the program trying to detect the VM, but for all the programs.
Moreover the authors claim that these are undocumented features and that they are not aware of any side effects.
12Related Work
The work by Guizani (Guizani et al., 2009) provides an effective solution for Server-Side Dynamic Code Analysis.
Small part of the solution deals with tricking the Split Personality malware that employ Memory Detection and VM Communication Channel Detection techniques.
13Related Work
Kalpa Vishnani et. al. 2011: Masks all the detection techniques used in Vmware.
14Related Work
Other works concentrate Detecting this category of malwares Running in host machine
Save the current state quickly restore to previous state
Virtual machines in the order of market share VMware, Virtual PC, and Virtual Box.
15VM Detection
Techniques Hardware fingerprinting Registry Check Process and File Check Memory Check Timing Analysis Communication Channel Check Invalid Instruction Check
16Hardware
Fingerprinting Involves looking for specific virtualized
hardware. VMs give an abstracted view of many hardware
components. Querying for such components reveals VM
presence. For Example: BIOS, Motherboard, SCSI
Controllers, USB Controllers, etc.
17
Hardware Fingerprinting Results
18Registry Check
The registry entries contain hundreds of references to the string containing the name of the VM, Ex. “Vmware”, VirtualPC and VirtualBox.
Checking the registry values for certain keys clearly reveals the VM presence.
19Registry Check
For Example:
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port1\Scsi Bus 0\Target Id 0\Logical Unit Id 0\Identifier
VMware, VMware Virtual S1.0 HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4D36E968-E325-11CE-BFC1-08002BE10318}\0000\DriverDesc
VMware SCSI Controller HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4D36E968-E325-11CE-BFC1-08002BE10318}\0000\ProviderName
VMware, Inc.
20Process and File
Check Check - VM specific processes and files
presence
Eg. VBoxService.exe : In VirtualBox for
synchronization with host
drivers like “vboxhook.dll” and “vpcbus” driver present in %SYSDIR%/drivers
21Memory Check
This involves looking for values of critical operating system data structures.
These data structures are relocated on a virtual machine so that they do not conflict with the host system's copies.
Store Interrupt Descriptor Table (SIDT), Store Local Descriptor Table( SLDT), Store Global Descriptor Table (SGDT), Store Task Register (STR), Store Machine Status Word (SMSW)
Redpill.exe, ScoopyNG.exe use this method.
22Timing Analysis
Obvious yet rare attack. Involves looking at a local Time Stamp Counter
(TSC) value. By noting down the time difference VM
presence is detected.
23VM Communication
Channel Check This check involves detecting the presence of a
host-guest communication channel. IN instruction and a magic number ‘VMXh’ VmDetect.exe uses this check. Not applicable to VirtualPC and VirtualBox. Runs in VMware without exception.
24Invalid Opcode Check
Specific to VirtualPC
Uses certain opcodes for guest host communication
In host system raise exception and no exception in VirtualPC.
25
Vmware Detection hardware details
motherboard serial number, graphics card and network adapter captions
Windows Management Instrumentation (WMI) contains classes hardware, display, registry etc.
Check for VM specific strings
HARDWARE FINGERPRINTING
26Registry Check
Windows Registry stores configuration settings low-level operating system components Applications running
Check for Strings like “VirtualPC”, “VBOX”, “VirtualBox” value that is specific to the corresponding virtual
machine being testing on.
27Process and File Check
Check - VM specific processes and files presence
Eg. VBoxService.exe : In VirtualBox for
synchronization with host
drivers like “vboxhook.dll” and “vpcbus” driver present in %SYSDIR%/drivers
28Memory Check
involves looking at the values of specific memory locations
STR (Store Task Register) stores the selector segment of the TR register
(Task Register) in the specified operand (memory or other general purpose register).
Value specific in Virtual Machine
29Invalid Opcode Check
Specific to VirtualPC
Uses certain opcodes for guest host communication
In host system raise exception.
30Detection of VM
running Linux Techniques: (tested on Vmware)
Hardware Fingerprinting
Dmesg check - prints the message buffer of the kernel
/proc file system check - interface to internal data structures in the kernel.
Communication channel check
31Dmesg and /proc file
system check Dmesg - prints the message buffer of the kernel
Shows diagnostic message showing presence of hardware during boot contain strings like “VMware”,
/proc file system - an interface to internal data structures in the kernel Contains system dependent information
32Communication
Channel Check IN instruction
Raises exception ““EXCEPTION PRIV INSTRUCTION” in host
Runs in VMware without exception initiates guest to host communication by
calling the “IN” instruction.
33VMwareDetect
Is the proof of concept tool. It employs the various VM detection techniques
to detect the presence of VMware virtual machine. Memory Check VM Communication Channel Check Hardware Fingerprinting Registry Check Timing Analysis
34
VMwareDetect
35
VirtualMachineDetect - VirtualPC Check using all the methods
In VirtualPC In Native Machine Hardware Fingerprinting BIOS American Megatrenda L900781
Graphics Card Virtual PC Integration Components S3 Trio32/64
NVDIA GeForce 310
Baseboard Manufacturer Microsoft co-orporation LENOVO
System Name VIRTUALXP User-think USB Controller USB Virtualisation Bus Driver Intel® 5 Series /3400 …
Registry Check SCSI: HARDWARE\\DEVICEMAP\\Scsi\\Scsi Port 0\\Scsi Bus 0\\Target Id 0\\Logical Unit Id 0
Virtual HD Hitachi HDS721050CLA362
Control class for usb : SYSTEM\\ControlSet001\\Control\\Class\\{36FC9E60-C465-11CF-8056-444553540000}\\0000
USB Virtualisation Bus Driver Intel® 5 Series /3400 …
Control class for graphics: SYSTEM\\ControlSet001\\Control\\Class\\{4D36E968-E325-11CE-BFC1-08002BE10318}\\0000
Virtual PC Integration Components S3 Trio32/64
NVDIA GeForce 310
Controlset for cd/dvd drive: SYSTEM\\CurrentControlSet\\Enum\\IDE
Disk Virtual_HD____1._1__ Registry not found
Invalid Opcode Did not raise exception Raised exception File Check Vpcubus Driver (Virtual USB Bus Driver) Present Not Present
Vpcgbus Driver (Virtual PC Guest Bus Driver) Present Not Present
Vpcuhub Driver (Virtual USB Hub Driver) Present Not Present
36
VirtualMachineDetect - VirtualBox Virtual Box running windows Host Windows Machine
Hardware Fingerprinting
BIOS 0 L900781
Graphics Card Virtual Box Graphics Adapter NVDIA GeForce 310
N/W adapter AMD PCNET Family PCI Ethernet Adapter WAN Miniport(SSTP) …
Processor Null CPU1
USB Controller Std Open HCD USB Host Controller Intel® 5 Series /3400 …
Registry Check
Dsdt: : HARDWARE\\ACPI\\DSDT VBOX__ Registry not present
Scsi P0 : HARDWARE\\DEVICEMAP\\Scsi\\Scsi Port 0\\Scsi Bus
0\\Target Id 0\\Logical Unit Id 0
VBOX HARDDISK Hitachi HDS721050CLA362
Scsi P1: HARDWARE\\DEVICEMAP\\Scsi\\Scsi Port 1\\Scsi Bus 0\\
Target Id 0\\Logical Unit Id 0
VBOX CD-ROM Null
Vedio Bios Version: HARDWARE\\DESCRIPTION\\System\
VideoBiosVersion
Oracle VM VirtualBox Version 4.1.2 VGA Bios Version 70.18.3E.00.05
System Bios Version: HARDWARE\\DESCRIPTION\\System\
SystemBiosVersion
VBOX-1 LENOVO-133
Instruction Check
STR (store task register) 28 0 40 00
File Check
VBOXHook.exe Present Not Present
VBOXTray Present Not Present
VBOXService.exe Present Not Present
37
Virtual Machine Detect
In VB
38Remote Detection
Scenario There is access to the terminal of a system
need not be administrator access
WMIC ( Windows management instrumentation command line) is used
39Masking Detection of
VM Using PIN API provided by Pin tool.
Can get all the instructions, the arguments and return value
Steps followed for masking Get each call made by binary. Check if matches a predefined list of calls. E.g.
RegEnumValueA Str LoadLibraryA __emit
40Masking Detection of
VM Provide false values if
VM specific values are read (matched from predefined list)
Eg. Registry read returns the value “VBOX” Pin Tool gets the return value and modifies it
in runtime. Registry read function returns modified value
41Masking Detection of
VM Binary does not detect – manipulated value
received.
This currently supports 64 and 32 bit OS 64 and 32 bit applications
42
Masking Detection of VMLoad Binary Detect if the binary
is 64 or 32 bit.Display the detection and give option to user to change it.
Detect the OS as 64/32 bit.
Detect the Underlying VM
Virtual PC VirtualBox
Register Check maskingInvalid Opcode Check Masking
File Check Masking
File Check Masking
Register Check Masking
Instruction Check Masking
Feedback
Save to db for further analysis
Execution of loaded binary completed
43Our Approach
44Our Approach
STEP 1: Maintain a list of all the hardware as well as registry querying API calls. Also maintain a list of all the VM specific instructions such as SIDT, SLDT, SGDT, STR, IN.
45Our Approach
Following is a partial list of API calls to be monitored. Hardware Querying APIs
SetupDiEnumDeviceInfo SetupDiGetDeviceInstanceId SetupDiGetDeviceRegistryProperty
Registry Querying APIs RegEnumKey RegEnumValue RegOpenKey RegQueryInfoKeyValue RegQueryMultipleValues RegQueryValue
46Our Approach
Step 2:Perform dynamic binary instrumentation of the sample under test in order to obtain its low level information as well as to intercept all the API calls made by it.
We hook into the sample under test by means of .dll injection.
This is achieved using the pin framework.
47Our Approach
Step3:Check to see if the sample under test makes a call or executes any of the monitored API calls or instructions respectively. If a match is found, set the OUTPUT to “Split Personality Malware Detected”. Also, log the activity and provide fake values to the sample so as to make it feel that it is running on a host system.
48Implementation
Designed, implemented and tested VMDetectGuard.
Implemented in the framework provided by the Pin tool released by Intel Corporation.
Pin is a tool for the instrumentation of programs.
We made use of its framework to intercept the various API calls and low level instructions executed by the sample under test.
49
COUNTERING HARDWARE FINGERPRINTING
Hardware emulation. APIs that query for BIOS, Motherboard, Processor,
Network Adapter. Ex. VM returns a value “none” for motherboard serial
number. VMDetectGuard returns a more appropriate string such as “.16LV3BS.CN70166983G1XF” instead.
50Countering Registry
Check VMDetectGuard monitors registry querying APIs such as the following: RegEnumKey RegEnumValue RegOpenKey RegQueryInfoKeyValue RegQueryMultipleValues RegQueryValue
If the output contains the string "VMware", our tool replaces this string with a more appropriate value that would have been returned on a non virtual system.
51
COUNTERING MEMORY CHECK
SIDT, SLDT, and SGDT and STR instructions are monitored.
The values of the target registers are then changed appropriately with the values that would have been obtained on a host OS.
52COUNTERING MEMORY
CHECK
53
COUNTERING VM COMMUNICATION CHANNEL CHECK
Monitor execution of the IN instruction. We change the value of the magic number . This leads to generation of “EXCEPTION PRIV
INSTRUCTION” exception.
54
COUNTERING TIMING ANALYSIS
Instructions such as CPUID and RDTSC (Read Time Stamp Counter) are monitored.
The tool maintains a log of each type of instruction executed.
If the threshold value for a particular type of instruction is exceeded, it logs this activity too.
Sample is tricked by deleting the CPUID instruction and modifying the values of ebx, ecx, and edx.
55VMDetectGuard
VMDetectGuard is our solution tool to counter Split Personality Malware.
VMDetectGuard runs in two different modes. VM Guard Mode Non VM Guard Mode
56VMDetectGuard
Output Generated by VMDetectGuard Result: Split Personality malware detected/not
detected. VM Specific Log Instruction Trace System Call Trace Registry Trace Opcode Mix Instruction Count Diff Tool Feature
57VMDetectGuard
58
Results & Analysis
59Redpill
Red Pill is a very well known VM detection tool by Rutkowska J.
Runs a single machine language instruction SIDT and analyses its result.
60
61
ScoopyNG
ScoopyNG is a very well known tool for VM detection developed by Klein T.
More reliable tool for VM detection in comparison to Red Pill.
It performs the following checks SIDT check SLDT check SGDT check STR check IN check (VMware communication channel)
62
63VmDetect
This is another well known proof of concept VM detecting sample that makes use of the VMware communication channel to detect VMware Presence.
64
65Backdoor.Win32.SdBot
.fmn Captured this malware from the
internet. Employs Memory check and Timing
Analysis mechanisms . In the absence of VMDetectGuard:
“This application cannot run under a Virtual Machine.”
In the presence of VMDetectGuard, it behaved malicious.
66
67
68VMDetectGuard
Running VMDetect in VirtualPCRunning VMDetect under masking tool
69VMDetectGuard
Running DetectionChecks in VirtualBox
Running DetectionChecks under masking tool
70Optimization
Before (sec) After (sec) % decrease in time taken
VirtualBox 167.310 112.411 32.08%
VirtualPC 294.786 205.953 30.13%
VMware 418.642 299.158 28.54%
Running Firefox binary under masking tool, in all the three virtual machines.
71
Results
Tested VMDetectGuard Malwares captured from internet Proof of concept tools
The results obtained after testing is given in table.
72
ResultsBinary Detection Technique Used Run without tool Run under tool
Virtual BoxVBDetect: calls others binaries for individual checks within.
Registry Check File and Process Check Instruction Check
Detected VirtualBox Did not detect VirtualBox
Rebhip File and Process Check Runs benignly Runs maliciously
VirtualPCVPCDetect: calls others binaries for individual checks within.
Registry Check File and Process Check Invalid Opcode Check
Detected VirtualPC Did not detect VirtualPC
Backdoor.Win32.SdBot.fmn File and Process Check Invalid Opcode Check
Displays a message, “This application cannot run under a Virtual Machine
Ran maliciously
VMDetect Invalid Opcode Check Detects VirtualPC Does not detect VirtualPC
Trojen.Karsh-252 Invalid Opcode Check Displays a message, “This application cannot run under a Virtual Machine
Ran Maliciously
73Conclusion
Split Personality malware is on a gradual rise.
Lack of academic research in this field.There does not exist any full-fledged
tool to counter Split Personality Malware.
We have designed, implemented and tested VMwareDetect, a proof of concept tool that detects the presence of Vmware.
74Conclusion
We also successfully designed and implemented VMDetectGuard, a tool to counter Split Personality malware.
It detects as well as tricks the split personality binaries.
Leads to the effective analysis of malware in the virtualized environment.
Increases productivity.