--- name: detecting-rootkit-activity-11aa001d883e description: 'Detects rootkit presence on compromised systems by identifying hidden processes, hooked system calls, modified kernel structures, and covert network connections using Volatility memory forensics, cross-view detection, and tools like GMER, rkhunter, chkrootkit, and RootkitRevealer. Use when standard tools (Task Manager, netstat, AV/EDR) show nothing abnormal but compromise is suspected. ' domain: cybersecurity subdomain: malware-analysis tags: - malware - rootkit - detection - kernel-analysis - memory-forensics version: 1.0.0 author: mahipal license: Apache-2.0 nist_csf: - DE.AE-02 - RS.AN-03 - ID.RA-01 - DE.CM-01 mitre_attack: - T1014 - T1547.006 - T1564.001 - T1574.006 --- # 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: ```bash # 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: ```bash # 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: ```bash # 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: ```bash # Linux rootkit detection with rkhunter rkhunter --check --skip-keypress --report-warnings-only # chkrootkit scanning chkrootkit -q # Windows: Compare filesystem views # Live system file listing vs Volatility filescan vol3 -f memory.dmp windows.filescan > mem_files.txt # Check for hidden registry keys vol3 -f memory.dmp windows.registry.hivelist vol3 -f memory.dmp windows.registry.printkey --key "SYSTEM\CurrentControlSet\Services" # Look for hidden services (loaded but not in service registry) vol3 -f memory.dmp windows.svcscan | grep -i "kernel" ``` ### Step 5: Network Connection Analysis Find hidden network connections and backdoors: ```bash # Memory-based network connection enumeration vol3 -f memory.dmp windows.netscan # Compare with live netstat (if available) to find hidden connections # Hidden connections: present in memory but not shown by netstat # Look for raw sockets (often used by rootkits for covert communication) vol3 -f memory.dmp windows.netscan | grep RAW # Check for network filter drivers (NDIS hooks) vol3 -f memory.dmp windows.driverscan | grep -i "ndis\|tcpip\|afd" # Analyze callback routines registered by drivers vol3 -f memory.dmp windows.callbacks ``` ### Step 6: Integrity Verification Verify system file and kernel integrity: ```bash # Check kernel code integrity (compare in-memory kernel to on-disk copy) vol3 -f memory.dmp windows.moddump --base 0xFFFFF80070000000 --dump # Compare SHA-256 of dumped ntoskrnl.exe with known-good copy # Windows: System File Checker (on live system) sfc /scannow # Linux: Package integrity verification rpm -Va # RPM-based systems debsums -c # Debian-based systems # Compare critical system binaries find /bin /sbin /usr/bin /usr/sbin -type f -exec sha256sum {} \; > current_hashes.txt # Compare against baseline: diff baseline_hashes.txt current_hashes.txt # YARA scan for known rootkit signatures vol3 -f memory.dmp yarascan.YaraScan --yara-file rootkit_rules.yar ``` ## Key Concepts | Term | Definition | |------|------------| | **Rootkit** | Malware designed to maintain persistent, privileged access while hiding its presence from system administrators and security tools | | **DKOM** | Direct Kernel Object Manipulation; technique of modifying kernel data structures (e.g., unlinking EPROCESS) to hide objects without hooking | | **SSDT Hooking** | Replacing entries in the System Service Descriptor Table to intercept and filter system call results (hide processes, files, connections) | | **Inline Hooking** | Patching the first instructions of a function with a jump to rootkit code; the rootkit can filter the function output before returning | | **Cross-View Detection** | Comparing results from multiple enumeration methods (linked list walk vs memory scan) to identify discrepancies caused by hiding | | **Kernel Driver** | Code running in kernel mode (Ring 0) with full system access; rootkits use malicious drivers to gain kernel-level control | | **Bootkits** | Rootkits that infect the boot process (MBR, VBR, or UEFI firmware) to load before the operating system and security tools | ## Tools & Systems - **Volatility**: Memory forensics framework providing cross-view detection, SSDT analysis, and kernel structure inspection for rootkit detection - **GMER**: Free Windows rootkit detection tool scanning for SSDT hooks, IDT hooks, IRP hooks, and hidden processes/files/registry - **rkhunter**: Linux rootkit detection tool checking for known rootkit signatures, suspicious files, and system binary modifications - **chkrootkit**: Linux tool for detecting rootkit presence through signature-based and anomaly-based checks - **Sysinternals RootkitRevealer**: Microsoft tool comparing Windows API results with raw filesystem/registry scans to find discrepancies ## Common Scenarios ### Scenario: Investigating a System Where Standard Tools Show No Compromise **Context**: An endpoint shows network beaconing to a known C2 IP in firewall logs, but the local EDR, Task Manager, and netstat show no suspicious processes or connections. A memory dump has been acquired for analysis. **Approach**: 1. Run Volatility `psscan` and compare with `pslist` to identify processes hidden via DKOM 2. Run `windows.ssdt` to check for system call hooks that filter process and network listings 3. Run `windows.malfind` to detect injected code in legitimate processes 4. Run `windows.netscan` to find network connections hidden from user-mode tools 5. Run `windows.driverscan` to identify malicious kernel drivers enabling the hiding 6. Dump the rootkit driver and analyze with Ghidra to understand its hooking mechanism 7. Check for boot persistence (MBR/VBR modifications, UEFI firmware implants) **Pitfalls**: - Running detection tools on the live compromised system (rootkit may hide from or subvert them) - Assuming kernel integrity because no SSDT hooks are found (rootkit may use DKOM or inline hooks instead) - Not checking for both user-mode and kernel-mode rootkit components (many rootkits have both) - Trusting the rootkit scanner results on a live system; always verify with offline memory forensics ## Output Format ``` ROOTKIT DETECTION ANALYSIS REPORT ==================================== Dump File: memory.dmp System: Windows 10 21H2 x64 Analysis Tool: Volatility 3.2 CROSS-VIEW DETECTION Process List Comparison: pslist processes: 127 psscan processes: 129 [!] HIDDEN PROCESSES: 2 PID 6784: sysmon64.exe (hidden rootkit component) PID 6812: netfilter.exe (hidden network filter) SSDT HOOK ANALYSIS [!] Entry 0x004A (NtQuerySystemInformation) hooked -> driver.sys+0x1200 [!] Entry 0x0055 (NtQueryDirectoryFile) hooked -> driver.sys+0x1400 [!] Entry 0x0119 (NtDeviceIoControlFile) hooked -> driver.sys+0x1600 Hook Target: driver.sys at 0xFFFFF800ABCD0000 (unsigned, suspicious) KERNEL DRIVER ANALYSIS [!] driver.sys - No digital signature, loaded at 0xFFFFF800ABCD0000 Size: 45,056 bytes SHA-256: abc123def456... IRP Hooks: IRP_MJ_CREATE, IRP_MJ_DEVICE_CONTROL Registry: HKLM\SYSTEM\CurrentControlSet\Services\MalDriver HIDDEN NETWORK CONNECTIONS PID 6812: 10.1.5.42:49152 -> 185.220.101.42:443 (ESTABLISHED) - Not visible via netstat or user-mode tools - Filtered by NtDeviceIoControlFile SSDT hook ROOTKIT CAPABILITIES - Process hiding (DKOM + SSDT) - File hiding (NtQueryDirectoryFile hook) - Network connection hiding (NtDeviceIoControlFile hook) - Kernel-mode persistence (driver service) REMEDIATION - Boot from clean media for offline remediation - Remove malicious driver from offline registry - Verify MBR/VBR/UEFI integrity for boot persistence - Full system rebuild recommended for kernel-level compromise ``` --- Source attribution: costrict-plugins-repo Original project: https://github.com/costrict-plugins-repo/mukul975-anthropic-cybersecurity-skills-cybersecurity-skills/blob/1b344d155f00bae5cf27d8eba9508e8f5050d904/skills/detecting-rootkit-activity/SKILL.md License: Apache-2.0 License information: https://www.apache.org/licenses/LICENSE-2.0 Original upstream instructions; downloaded from Mega AI Hub. ## Upstream license notice Apache License Version 2.0, January 2004 http://www.apache.org/licenses/ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 1. 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See the License for the specific language governing permissions and limitations under the License. # Mega AI Hub resource metadata Creator / publisher: costrict-plugins-repo Original project: https://github.com/costrict-plugins-repo/mukul975-anthropic-cybersecurity-skills-cybersecurity-skills/blob/1b344d155f00bae5cf27d8eba9508e8f5050d904/skills/detecting-rootkit-activity/SKILL.md Attribution basis: Source repository record Fields of work: Development & Engineering Roles: Security Engineer Specialties: Specialty not specified Tools: Chkrootkit, Gmer, Rkhunter, Rootkit Revealer, Sysinternals Tools, Volatility Country applicability: Country not specified Classification basis: Source catalog labels Instruction SHA-256: 4657d6a7b15a75cdd2e2819ae45ac117206ca3f2a4f753024e9cd88b2d76dee9