0xdeadbeefnetwork-KKYUMPoC/ANALYSIS.md

KKYUM.sys Driver Analysis Report

Executive Summary

KKYUM.sys is a Windows x64 kernel driver (26,768 bytes) that appears to be designed for process memory manipulation and interaction with the Windows input subsystem (mouse/keyboard drivers) and GUI components (win32k).

SHA256: 72BD55F4459C992B9CAA1A33CB6862F1F3085CA35839C58DEE8B75DB22CA605F

File Metadata

• Architecture: x86-64 (x86:LE:64:default)
• Platform: Windows
• Type: Kernel Driver (.sys)
• Size: 26,768 bytes
• Framework: Windows Driver Framework (WDF/KMDF)

Memory Layout

Section          Start Address  Size    Permissions
-------          -------------  ----    -----------
Headers          0x140000000    0x400   R--
.text            0x140001000    0x2600  R-X  (executable code)
.rdata           0x140004000    0xc00   R--  (read-only data)
.data            0x140005000    0x4e0   RW-  (writable data)
.pdata           0x140006000    0x200   R--  (exception handling)
INIT             0x140007000    0x600   R-X  (initialization code)
.reloc           0x140008000    0x200   R--  (relocations)
tdb              0xff00000000  0x1850  RW-  (type database)

Key Findings

1. Device Interface

The driver creates a device object and symbolic link for usermode communication:

• Device: \Device\KKYUM
• Symbolic Link: \DosDevices\KKYUM

This allows usermode applications to open a handle to the driver and send I/O control codes (IOCTLs).

2. Process Memory Manipulation Capabilities

The driver imports critical functions for reading/writing process memory:

• MmCopyVirtualMemory - Copies memory between process address spaces (referenced 3 times)

  • This is a powerful kernel function that allows reading/writing to any process
  • Commonly used by game cheats and malware for process injection

• PsLookupProcessByProcessId - Locates process structure by PID

• KeStackAttachProcess / KeUnstackDetachProcess - Attaches to target process context

• IoGetCurrentProcess - Gets current process

• PsGetProcessWow64Process - Gets WOW64 information (32-bit on 64-bit)

3. Input Subsystem Targeting

String references indicate targeting of mouse and keyboard drivers:

\Driver\mouclass    - Mouse class driver
\Driver\kbdclass    - Keyboard class driver  
\Driver\kbdhid      - Keyboard HID driver
\Driver\mouhid      - Mouse HID driver
\Driver\i8042prt    - PS/2 keyboard/mouse port driver

This suggests potential capabilities for:

• Input injection (sending fake mouse/keyboard inputs)
• Input filtering/monitoring (reading user inputs)
• Bypassing user-mode input validation

4. Windows GUI Subsystem Access

References to win32k components:

• win32kbase.sys - Windows kernel-mode base subsystem
• win32kfull.sys - Windows kernel-mode full subsystem
• ValidateHwnd - Function for validating window handles

This could indicate:

• Direct manipulation of GUI elements
• Bypassing user-mode window message queues
• Window handle validation/enumeration

5. Process Targeting

• winlogon.exe - Windows logon process
  • This is a critical Windows process that handles login/logout
  • Targeting it could indicate credential harvesting or session manipulation

6. System Information Queries

• ZwQuerySystemInformation - Queried twice
  • Can retrieve system-level information
  • Often used for anti-detection or process enumeration

7. Dynamic Function Resolution

• RtlFindExportedRoutineByName - Finds kernel functions by name
  • Allows runtime resolution of undocumented kernel functions
  • Common technique to avoid static analysis detection

Security Implications

Potential Malicious Uses:

1. Game Cheating/Anti-Cheat Bypass

   • Read/write game process memory
   • Inject fake input events
   • Bypass anti-cheat detection

2. Keylogging/Input Interception

   • Monitor keyboard/mouse inputs at kernel level
   • Bypass user-mode security software

3. Process Injection

   • Inject code into arbitrary processes
   • Escalate privileges
   • Hide malicious activity

4. Credential Harvesting

   • Target winlogon.exe for credentials
   • Read password memory from processes

5. Rootkit Capabilities

   • Kernel-level code execution
   • Hide processes/files/network connections
   • Disable security software

Function Analysis

• Total Functions: 90
• Entry Point: 0x1400029e0
• Notable Imports:
  • Memory management: ExAllocatePool, ExFreePoolWithTag, MmMapLockedPagesSpecifyCache
  • Device management: IoCreateDevice, IoDeleteDevice, IoCreateSymbolicLink
  • Process operations: MmCopyVirtualMemory, KeStackAttachProcess
  • Object management: ObReferenceObjectByName, ObfDereferenceObject

KMDF Framework

The driver uses the Kernel-Mode Driver Framework (KMDF):

• WdfVersionBind - Binds to WDF runtime
• WdfLdrQueryInterface - Queries WDF loader
• WdfVersionBindClass - Binds to WDF class

This provides a structured framework for driver development but also indicates a relatively modern/well-structured implementation.

Static Analysis Pattern

Found binary pattern (likely signature for code searching):

E8 ? ? ? ? 8B ? 85 C0 75 0E

This appears to be a pattern for locating specific code sequences, possibly for hooking or patching.

Recommendations

For Security Researchers:

1. Dynamic Analysis: Run in isolated VM with process/registry monitoring
2. IOCTL Analysis: Reverse engineer IOCTL handlers to understand full capabilities
3. Decompile Entry Point: Examine DriverEntry and IRP handlers
4. Memory Analysis: Monitor MmCopyVirtualMemory calls to see what it's reading/writing
5. Input Monitoring: Check if it hooks keyboard/mouse driver chains

For System Administrators:

1. This driver should be treated as potentially malicious
2. Do NOT load on production systems
3. Check for persistence: Registry SYSTEM\CurrentControlSet\Services\KKYUM
4. Monitor for: Unsigned driver loading attempts
5. Detection: SHA256 hash can be used in EDR/AV signatures

IOC (Indicators of Compromise)

• File Hash: 72BD55F4459C992B9CAA1A33CB6862F1F3085CA35839C58DEE8B75DB22CA605F
• Device Name: \Device\KKYUM
• Symbolic Link: \DosDevices\KKYUM
• Service Name: Likely "KKYUM" (typical convention)

Next Steps for Analysis

1. Decompile DriverEntry - Understand initialization and IOCTL registration
2. Analyze IRP Handlers - Reverse engineer DeviceIoControl handlers
3. Trace Memory Operations - Dynamic analysis of MmCopyVirtualMemory usage
4. IOCTL Fuzzing - Test driver stability and find vulnerabilities
5. Signature Creation - Create YARA rule for detection
6. Behavioral Analysis - Run in VM and monitor kernel API calls

Conclusion

KKYUM.sys is a kernel driver with capabilities for:

• ✅ Process memory reading/writing (via MmCopyVirtualMemory)
• ✅ Input system manipulation (mouse/keyboard driver references)
• ✅ GUI subsystem interaction (win32k references)
• ✅ Process targeting (winlogon.exe)
• ✅ Dynamic function resolution (anti-analysis)

Risk Level: HIGH - This driver has all the capabilities needed for malicious activities including game cheating, keylogging, process injection, and rootkit functionality.

Recommendation: Treat as malicious until proven otherwise. Do not load on any system with valuable data.