SHARE PERMISSIONS FAQ

Share permissions and NTFS permissions serve different purposes and work together to control access:

Share Permissions:

• Scope - Only apply to network access (UNC paths like \\server\share)
• Granularity - Three levels: Read, Change, Full Control
• Application - Entire shared folder and all contents
• Inheritance - No inheritance concept
• Purpose - Control who can access the share over the network

NTFS Permissions:

• Scope - Apply to both local and network access
• Granularity - Detailed: Read, Write, Execute, Modify, Full Control, etc.
• Application - Individual files and folders
• Inheritance - Permissions flow from parent to child objects
• Purpose - Detailed file-level security

How they work together:

# Effective Permission = Most Restrictive of: Share Permission AND NTFS Permission Examples: Share: Full Control + NTFS: Read = Read access Share: Read + NTFS: Modify = Read access Share: Change + NTFS: Full Control = Change access

Key differences summary:

• Local access - Only NTFS permissions apply
• Network access - Both share and NTFS permissions apply
• Most restrictive wins - The tightest permission is enforced
• Share permissions override - Can't grant more than share allows

This common issue occurs when NTFS permissions allow access but share permissions don't:

Most common causes:

• Restrictive share permissions - Share only grants 'Read' but user needs 'Change'
• User not in share ACL - Share permissions don't include the user/group
• Domain vs local authentication - Different accounts for local and network access
• Firewall/network issues - Not permission-related at all

Diagnostic steps:

# Check share permissions net share ShareName # PowerShell method for detailed info Get-SmbShare -Name ShareName | Get-SmbShareAccess # Test network connectivity Test-NetConnection ServerName -Port 445 net use \\ServerName\ShareName # Check effective permissions smbcacls //server/share folder -U domain\username

Troubleshooting checklist:

• Verify share exists - net view \\servername
• Check share permissions - Does user have appropriate share access?
• Test with domain admin - If admin works, it's a permission issue
• Compare local vs UNC path - Same file, different access methods
• Check group membership - whoami /groups on both client and server

Quick fixes:

• Grant share permissions - Add user/group to share ACL
• Use 'Change' permission - Instead of just 'Read'
• Add 'Authenticated Users' - To share permissions for broader access
• Reset credentials - net use /delete \\server\share

Proper share permission configuration balances security with usability:

Recommended share permission strategy:

• Default approach - Everyone: Full Control on shares, restrict via NTFS
• High-security approach - Specific groups only, layered with NTFS
• Department-based - Department groups get Change, others get Read
• Administrative - Administrators get Full Control always

Share permission levels explained:

# Read Permission Includes: - List folder contents - Read file data - Read attributes and extended attributes - Read permissions # Change Permission Includes: - All Read permissions PLUS: - Create files and folders - Change file data - Delete files and folders - Change attributes # Full Control Includes: - All Change permissions PLUS: - Change permissions - Take ownership

Security best practices:

• Remove Everyone group - Use 'Authenticated Users' instead
• Don't use Full Control - Unless users need to change permissions
• Layer with NTFS - Share permissions are the 'outer gate'
• Regular audits - Review share access quarterly
• Document exceptions - Why certain users have elevated access

PowerShell share management:

# Create new share with proper permissions New-SmbShare -Name "DeptShare" -Path "C:\DeptData" -FullAccess "Administrators" -ChangeAccess "DOMAIN\DeptUsers" -ReadAccess "DOMAIN\DeptRead" # Modify existing share permissions Grant-SmbShareAccess -Name "DeptShare" -AccountName "DOMAIN\NewUser" -AccessRight Change Revoke-SmbShareAccess -Name "DeptShare" -AccountName "Everyone" # Audit current shares Get-SmbShare | ForEach {Get-SmbShareAccess -Name $_.Name}

Understanding effective permissions requires knowing how share and NTFS permissions interact:

Permission calculation rules:

• Local access - Only NTFS permissions apply
• Network access - Most restrictive of Share AND NTFS
• Group membership - User gets cumulative permissions from all groups
• Deny overrides Allow - Any deny permission blocks access

Examples of effective permissions:

# Example 1: Share limits access Share Permission: Read NTFS Permission: Full Control Effective Permission: Read (share is more restrictive) # Example 2: NTFS limits access Share Permission: Full Control NTFS Permission: Read & Execute Effective Permission: Read & Execute (NTFS is more restrictive) # Example 3: Multiple group memberships User in Group A: Share=Change, NTFS=Read User in Group B: Share=Read, NTFS=Modify Effective: Read (most restrictive share) with Read (most restrictive NTFS)

Tools for checking effective permissions:

• Windows GUI - Security tab -> Advanced -> Effective Access
• PowerShell - Get-Acl and Get-SmbShareAccess commands
• Sysinternals AccessChk - Command-line effective permissions tool
• Permissions Reporter - Automated effective permissions analysis

PowerShell effective permission check:

# Check user's share access Get-SmbShareAccess -Name "ShareName" | Where {$_.Name -eq "Domain\Username"} # Check NTFS permissions $acl = Get-Acl "\\Server\Share\Folder" $acl.Access | Where {$_.IdentityReference -eq "Domain\Username"} # Combine results to determine effective permissions # (Manual analysis required based on rules above)

The answer depends on your security requirements and network architecture:

NTFS-focused approach (Recommended):

• Share permissions - Set to 'Full Control' for Everyone or Authenticated Users
• NTFS permissions - Handle all detailed access control
• Benefits - Single permission system, works locally and remotely
• Best for - Most environments, simplifies management

Layered security approach:

• Share permissions - Broad department/role-based access
• NTFS permissions - Detailed file and folder access
• Benefits - Defense in depth, granular control
• Best for - High-security environments, compliance requirements

Share-focused approach (Not recommended):

• Share permissions - Handle most access control
• NTFS permissions - Minimal or default settings
• Problems - No local access control, limited granularity
• Only use if - Legacy compatibility requirements

Decision matrix:

Choose NTFS-focused if: ✓ Mixed local and network access ✓ Need file-level permissions ✓ Want simplified management ✓ Use inheritance features Choose Layered approach if: ✓ High security requirements ✓ Compliance mandates defense-in-depth ✓ Network-only access ✓ Want permission redundancy

Implementation best practices:

• Start simple - NTFS-focused, add share restrictions as needed
• Document strategy - Make sure team understands approach
• Regular audits - Verify permissions match documentation
• Test thoroughly - Verify access from different scenarios

Shared folder access denied errors require systematic troubleshooting of both permission layers:

Step 1: Verify basic connectivity

# Test network connectivity to server ping ServerName telnet ServerName 445 # Check if share exists and is accessible net view \\ServerName dir \\ServerName\ShareName

Step 2: Check share permissions

# View share permissions net share ShareName # PowerShell detailed view Get-SmbShare -Name ShareName | Get-SmbShareAccess # Test with different credentials net use \\ServerName\ShareName /user:domain\username

Step 3: Verify NTFS permissions

# Check NTFS permissions on shared folder icacls "C:\SharedFolder" # Check effective permissions for user icacls "C:\SharedFolder" /findsid domain\username # Verify group membership whoami /groups

Common resolution steps:

• Clear cached credentials - net use * /delete
• Check UAC settings - May require elevation
• Verify group membership - User may not be in required groups
• Test with domain admin - Isolate permission vs other issues
• Check deny permissions - Look for explicit deny entries

Advanced troubleshooting:

# Enable detailed logging auditpol /set /subcategory:"File Share" /success:enable /failure:enable auditpol /set /subcategory:"File System" /success:enable /failure:enable # Check event logs Get-EventLog -LogName Security | Where {$_.EventID -in @(5140,5145)} # Share access events Get-EventLog -LogName Security | Where {$_.EventID -eq 4656} # File access events