Memory Forensics
Comprehensive techniques for acquiring, analyzing, and extracting artifacts from memory dumps for incident response and malware analysis.
Memory Acquisition
Live Acquisition Tools
Windows
# WinPmem (Recommended) winpmem_mini_x64.exe memory.raw # DumpIt DumpIt.exe # Belkasoft RAM Capturer # GUI-based, outputs raw format # Magnet RAM Capture # GUI-based, outputs raw format
Linux
# LiME (Linux Memory Extractor) sudo insmod lime.ko "path=/tmp/memory.lime format=lime" # /dev/mem (limited, requires permissions) sudo dd if=/dev/mem of=memory.raw bs=1M # /proc/kcore (ELF format) sudo cp /proc/kcore memory.elf
macOS
# osxpmem sudo ./osxpmem -o memory.raw # MacQuisition (commercial)
Virtual Machine Memory
# VMware: .vmem file is raw memory cp vm.vmem memory.raw # VirtualBox: Use debug console vboxmanage debugvm "VMName" dumpvmcore --filename memory.elf # QEMU virsh dump <domain> memory.raw --memory-only # Hyper-V # Checkpoint contains memory state
Volatility 3 Framework
Installation and Setup
# Install Volatility 3 pip install volatility3 # Install symbol tables (Windows) # Download from https://downloads.volatilityfoundation.org/volatility3/symbols/ # Basic usage vol -f memory.raw <plugin> # With symbol path vol -f memory.raw -s /path/to/symbols windows.pslist
Essential Plugins
Process Analysis
# List processes vol -f memory.raw windows.pslist # Process tree (parent-child relationships) vol -f memory.raw windows.pstree # Hidden process detection vol -f memory.raw windows.psscan # Process memory dumps vol -f memory.raw windows.memmap --pid <PID> --dump # Process environment variables vol -f memory.raw windows.envars --pid <PID> # Command line arguments vol -f memory.raw windows.cmdline
Network Analysis
# Network connections vol -f memory.raw windows.netscan # Network connection state vol -f memory.raw windows.netstat
DLL and Module Analysis
# Loaded DLLs per process vol -f memory.raw windows.dlllist --pid <PID> # Find hidden/injected DLLs vol -f memory.raw windows.ldrmodules # Kernel modules vol -f memory.raw windows.modules # Module dumps vol -f memory.raw windows.moddump --pid <PID>
Memory Injection Detection
# Detect code injection vol -f memory.raw windows.malfind # VAD (Virtual Address Descriptor) analysis vol -f memory.raw windows.vadinfo --pid <PID> # Dump suspicious memory regions vol -f memory.raw windows.vadyarascan --yara-rules rules.yar
Registry Analysis
# List registry hives vol -f memory.raw windows.registry.hivelist # Print registry key vol -f memory.raw windows.registry.printkey --key "Software\Microsoft\Windows\CurrentVersion\Run" # Dump registry hive vol -f memory.raw windows.registry.hivescan --dump
File System Artifacts
# Scan for file objects vol -f memory.raw windows.filescan # Dump files from memory vol -f memory.raw windows.dumpfiles --pid <PID> # MFT analysis vol -f memory.raw windows.mftscan
Linux Analysis
# Process listing vol -f memory.raw linux.pslist # Process tree vol -f memory.raw linux.pstree # Bash history vol -f memory.raw linux.bash # Network connections vol -f memory.raw linux.sockstat # Loaded kernel modules vol -f memory.raw linux.lsmod # Mount points vol -f memory.raw linux.mount # Environment variables vol -f memory.raw linux.envars
macOS Analysis
# Process listing vol -f memory.raw mac.pslist # Process tree vol -f memory.raw mac.pstree # Network connections vol -f memory.raw mac.netstat # Kernel extensions vol -f memory.raw mac.lsmod
Analysis Workflows
Malware Analysis Workflow
# 1. Initial process survey vol -f memory.raw windows.pstree > processes.txt vol -f memory.raw windows.pslist > pslist.txt # 2. Network connections vol -f memory.raw windows.netscan > network.txt # 3. Detect injection vol -f memory.raw windows.malfind > malfind.txt # 4. Analyze suspicious processes vol -f memory.raw windows.dlllist --pid <PID> vol -f memory.raw windows.handles --pid <PID> # 5. Dump suspicious executables vol -f memory.raw windows.pslist --pid <PID> --dump # 6. Extract strings from dumps strings -a pid.<PID>.exe > strings.txt # 7. YARA scanning vol -f memory.raw windows.yarascan --yara-rules malware.yar
Incident Response Workflow
# 1. Timeline of events vol -f memory.raw windows.timeliner > timeline.csv # 2. User activity vol -f memory.raw windows.cmdline vol -f memory.raw windows.consoles # 3. Persistence mechanisms vol -f memory.raw windows.registry.printkey \ --key "Software\Microsoft\Windows\CurrentVersion\Run" # 4. Services vol -f memory.raw windows.svcscan # 5. Scheduled tasks vol -f memory.raw windows.scheduled_tasks # 6. Recent files vol -f memory.raw windows.filescan | grep -i "recent"
Data Structures
Windows Process Structures
// EPROCESS (Executive Process) typedef struct _EPROCESS { KPROCESS Pcb; // Kernel process block EX_PUSH_LOCK ProcessLock; LARGE_INTEGER CreateTime; LARGE_INTEGER ExitTime; // ... LIST_ENTRY ActiveProcessLinks; // Doubly-linked list ULONG_PTR UniqueProcessId; // PID // ... PEB* Peb; // Process Environment Block // ... } EPROCESS; // PEB (Process Environment Block) typedef struct _PEB { BOOLEAN InheritedAddressSpace; BOOLEAN ReadImageFileExecOptions; BOOLEAN BeingDebugged; // Anti-debug check // ... PVOID ImageBaseAddress; // Base address of executable PPEB_LDR_DATA Ldr; // Loader data (DLL list) PRTL_USER_PROCESS_PARAMETERS ProcessParameters; // ... } PEB;
VAD (Virtual Address Descriptor)
typedef struct _MMVAD { MMVAD_SHORT Core; union { ULONG LongFlags; MMVAD_FLAGS VadFlags; } u; // ... PVOID FirstPrototypePte; PVOID LastContiguousPte; // ... PFILE_OBJECT FileObject; } MMVAD; // Memory protection flags #define PAGE_EXECUTE 0x10 #define PAGE_EXECUTE_READ 0x20 #define PAGE_EXECUTE_READWRITE 0x40 #define PAGE_EXECUTE_WRITECOPY 0x80
Detection Patterns
Process Injection Indicators
# Malfind indicators # - PAGE_EXECUTE_READWRITE protection (suspicious) # - MZ header in non-image VAD region # - Shellcode patterns at allocation start # Common injection techniques # 1. Classic DLL Injection # - VirtualAllocEx + WriteProcessMemory + CreateRemoteThread # 2. Process Hollowing # - CreateProcess (SUSPENDED) + NtUnmapViewOfSection + WriteProcessMemory # 3. APC Injection # - QueueUserAPC targeting alertable threads # 4. Thread Execution Hijacking # - SuspendThread + SetThreadContext + ResumeThread
Rootkit Detection
# Compare process lists vol -f memory.raw windows.pslist > pslist.txt vol -f memory.raw windows.psscan > psscan.txt diff pslist.txt psscan.txt # Hidden processes # Check for DKOM (Direct Kernel Object Manipulation) vol -f memory.raw windows.callbacks # Detect hooked functions vol -f memory.raw windows.ssdt # System Service Descriptor Table # Driver analysis vol -f memory.raw windows.driverscan vol -f memory.raw windows.driverirp
Credential Extraction
# Dump hashes (requires hivelist first) vol -f memory.raw windows.hashdump # LSA secrets vol -f memory.raw windows.lsadump # Cached domain credentials vol -f memory.raw windows.cachedump # Mimikatz-style extraction # Requires specific plugins/tools
YARA Integration
Writing Memory YARA Rules
rule Suspicious_Injection { meta: description = "Detects common injection shellcode" strings: // Common shellcode patterns $mz = { 4D 5A } $shellcode1 = { 55 8B EC 83 EC } // Function prologue $api_hash = { 68 ?? ?? ?? ?? 68 ?? ?? ?? ?? E8 } // Push hash, call condition: $mz at 0 or any of ($shellcode*) } rule Cobalt_Strike_Beacon { meta: description = "Detects Cobalt Strike beacon in memory" strings: $config = { 00 01 00 01 00 02 } $sleep = "sleeptime" $beacon = "%s (admin)" wide condition: 2 of them }
Scanning Memory
# Scan all process memory vol -f memory.raw windows.yarascan --yara-rules rules.yar # Scan specific process vol -f memory.raw windows.yarascan --yara-rules rules.yar --pid 1234 # Scan kernel memory vol -f memory.raw windows.yarascan --yara-rules rules.yar --kernel
String Analysis
Extracting Strings
# Basic string extraction strings -a memory.raw > all_strings.txt # Unicode strings strings -el memory.raw >> all_strings.txt # Targeted extraction from process dump vol -f memory.raw windows.memmap --pid 1234 --dump strings -a pid.1234.dmp > process_strings.txt # Pattern matching grep -E "(https?://|[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})" all_strings.txt
FLOSS for Obfuscated Strings
# FLOSS extracts obfuscated strings floss malware.exe > floss_output.txt # From memory dump floss pid.1234.dmp
Best Practices
Acquisition Best Practices
- Minimize footprint: Use lightweight acquisition tools
- Document everything: Record time, tool, and hash of capture
- Verify integrity: Hash memory dump immediately after capture
- Chain of custody: Maintain proper forensic handling
Analysis Best Practices
- Start broad: Get overview before deep diving
- Cross-reference: Use multiple plugins for same data
- Timeline correlation: Correlate memory findings with disk/network
- Document findings: Keep detailed notes and screenshots
- Validate results: Verify findings through multiple methods
Common Pitfalls
- Stale data: Memory is volatile, analyze promptly
- Incomplete dumps: Verify dump size matches expected RAM
- Symbol issues: Ensure correct symbol files for OS version
- Smear: Memory may change during acquisition
- Encryption: Some data may be encrypted in memory