Detecting Rootkit Activity

When to Use

• System shows signs of compromise but standard tools (Task Manager, netstat) show nothing abnormal
• Antivirus/EDR detects rootkit signatures but cannot identify the specific hiding mechanism
• Memory forensics reveals discrepancies between kernel data structures and user-mode tool output
• Investigating a persistent threat that survives remediation attempts and system reboots
• Validating system integrity after a suspected kernel-level compromise

Do not use as a first-line detection method; start with standard malware triage and escalate to rootkit analysis when hiding behavior is suspected.

Prerequisites

• Volatility 3 for memory forensics and kernel structure analysis
• GMER or Rootkit Revealer (Windows) for live system scanning
• rkhunter and chkrootkit (Linux) for filesystem and process integrity checks
• Sysinternals tools (Process Explorer, Autoruns, RootkitRevealer) for Windows analysis
• Memory dump from the suspected system (WinPmem, LiME)
• Clean baseline of the OS for comparison (known-good kernel module hashes)

Workflow

Step 1: Cross-View Detection for Hidden Processes

Compare process lists from different data sources to find discrepancies:

# Volatility: Compare process enumeration methods
# pslist - walks ActiveProcessLinks (EPROCESS linked list - what rootkits manipulate)
vol3 -f memory.dmp windows.pslist > pslist_output.txt

# psscan - scans physical memory for EPROCESS pool tags (rootkit-resistant)
vol3 -f memory.dmp windows.psscan > psscan_output.txt

# Compare outputs to find hidden processes
python3 << 'PYEOF'
pslist_pids = set()
psscan_pids = set()

with open("pslist_output.txt") as f:
    for line in f:
        parts = line.split()
        if len(parts) > 1 and parts[1].isdigit():
            pslist_pids.add(int(parts[1]))

with open("psscan_output.txt") as f:
    for line in f:
        parts = line.split()
        if len(parts) > 1 and parts[1].isdigit():
            psscan_pids.add(int(parts[1]))

hidden = psscan_pids - pslist_pids
if hidden:
    print(f"[!] HIDDEN PROCESSES DETECTED (in psscan but not pslist):")
    for pid in hidden:
        print(f"    PID: {pid}")
else:
    print("[*] No hidden processes detected via cross-view analysis")
PYEOF

Step 2: Detect System Call Hooking

Identify hooks in the System Service Descriptor Table (SSDT) and Import Address Tables:

# Check SSDT for hooked system calls
vol3 -f memory.dmp windows.ssdt

# Identify hooks pointing outside ntoskrnl.exe or win32k.sys
vol3 -f memory.dmp windows.ssdt | grep -v "ntoskrnl\|win32k"

# Check for Inline hooks (detour patching)
vol3 -f memory.dmp windows.apihooks --pid 4  # System process

# IDT (Interrupt Descriptor Table) analysis
vol3 -f memory.dmp windows.idt

# Check for IRP (I/O Request Packet) hooking on drivers
vol3 -f memory.dmp windows.driverscan
vol3 -f memory.dmp windows.driverirp

Types of Rootkit Hooks:
━━━━━━━━━━━━━━━━━━━━━
SSDT Hook:         Modifies System Service Descriptor Table entries to redirect
                   system calls through rootkit code (filters process/file listings)

IAT Hook:          Patches Import Address Table of a process to intercept API calls
                   before they reach the kernel

Inline Hook:       Overwrites the first bytes of a function with a JMP to rootkit code
                   (detour/trampoline technique)

IRP Hook:          Intercepts I/O Request Packets to filter disk/network operations
                   at the driver level

DKOM:              Direct Kernel Object Manipulation - unlinking structures like
                   EPROCESS from the ActiveProcessLinks list without hooking

Step 3: Analyze Kernel Modules and Drivers

Identify unauthorized kernel drivers that may be rootkit components:

# List all loaded kernel modules
vol3 -f memory.dmp windows.modules

# Scan for drivers in memory (including hidden/unlinked)
vol3 -f memory.dmp windows.driverscan

# Compare module lists to find hidden drivers
vol3 -f memory.dmp windows.modscan > modscan.txt
vol3 -f memory.dmp windows.modules > modules.txt

# Check driver signatures and verify against known-good baselines
vol3 -f memory.dmp windows.verinfo

# Dump suspicious driver for static analysis
vol3 -f memory.dmp windows.moddump --base 0xFFFFF80012340000 --dump

Step 4: Detect File and Registry Hiding

Identify files and registry keys hidden by the rootkit:

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