Disk Serial Number

DiskSerialNumber is a sandbox setting in Sandboxie Ini available since v1.15.2 / 5.70.2. This setting allows assigning custom serial numbers to specific disk devices within sandboxes, working in conjunction with Hide Disk Serial Number.

Syntax

DiskSerialNumber=<DeviceName>,<SerialNumber>

• DeviceName: Windows device name (e.g., HarddiskVolume1, HarddiskVolume2)
• SerialNumber: Custom serial number in hexadecimal format (with or without hyphens)

Example Usage

[DefaultBox]

HideDiskSerialNumber=y
DiskSerialNumber=HarddiskVolume1,1234-ABCD
DiskSerialNumber=HarddiskVolume2,5678-EFGH
DiskSerialNumber=HarddiskVolume3,9ABC-DEF0

Prerequisites

• Requires HideDiskSerialNumber=y to be enabled in the same sandbox¹.
• Without this prerequisite, the DiskSerialNumber settings are ignored.

Serial Number Formats

Supported Formats

• Hyphenated: 1234-ABCD, AA-BB-CC-DD.
• Plain: 1234ABCD, AABBCCDD.
• Mixed: Any combination of hex digits with optional hyphens.

Valid Examples

DiskSerialNumber=HarddiskVolume1,1234ABCD
DiskSerialNumber=HarddiskVolume2,12-34-AB-CD
DiskSerialNumber=HarddiskVolume3,12345678
DiskSerialNumber=HarddiskVolume4,DEADBEEF

Invalid Formats

• Non-hexadecimal characters (G-Z).
• Odd number of hex digits.
• Empty strings.
• Special characters other than hyphens.

Device Name Discovery

Method 1: Using WMIC Command

Run in Command Prompt to list available disk volumes:

wmic logicaldisk get caption,volumeserialnumber,deviceid

Method 2: Using Disk Management

1. Open Disk Management (diskmgmt.msc).
2. Right-click on volumes to see properties.
3. Note the volume labels and drive letters.

Method 3: Registry Inspection

Check registry key: HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices

Method 4: Testing with Random Values

1. Set test configurations:

DiskSerialNumber=HarddiskVolume1,11111111
DiskSerialNumber=HarddiskVolume2,22222222
DiskSerialNumber=HarddiskVolume3,33333333

1. Run vol C:, vol D:, etc., in the sandbox to identify which device corresponds to which drive.

Technical Implementation

Device Path Resolution

• Sandboxie extracts device names from Windows NT paths with \Device\ prefix².
• Device name parsing stops at the next backslash or string terminator³.
• Failed device extraction results in random serial number generation⁴.

Hexadecimal Processing

• Custom parser handles both hyphenated and plain hex formats⁵.
• Invalid hex strings trigger fallback to random generation⁶.
• Byte order is automatically swapped to match Windows DWORD format⁷.

Caching Mechanism

• Serial numbers are cached per session for performance⁸
• Thread-safe implementation using critical sections⁹
• Cache keys are based on original hardware serial numbers¹⁰

Use Cases

Application Testing

• Test software behavior with specific disk serial number patterns.
• Simulate different hardware configurations.
• Debug serial number-dependent functionality.

Privacy Enhancement

• Replace real hardware identifiers with known values.
• Create consistent sandbox fingerprints.
• Prevent hardware-based tracking.

Troubleshooting

Common Issues

Setting Not Applied

• Ensure HideDiskSerialNumber=y is enabled.
• Verify correct device name format.
• Check hexadecimal string validity.

Wrong Device Targeted

• Use device discovery methods to identify correct names.
• Test with unique serial numbers to verify mapping.

Random Values Still Returned

• Invalid hex format triggers random fallback.
• Device name mismatch results in random generation.
• Missing HideDiskSerialNumber prerequisite.

Related Settings

• Hide Disk Serial Number - Required prerequisite setting.
• Hide Firmware Info - Hides additional hardware identifiers.
• Hide Network Adapter MAC - Customizes network adapter identifiers.
• Random Registry UID - Randomizes registry-based unique identifiers.

Configuration Availability

• INI Configuration: Available
• Plus UI: Not available (INI-only setting)
• Classic UI: Not available

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1. Prerequisite Check: The HideDiskSerialNumber setting must be enabled for device-specific serial number mapping to function (kernel.c). ↩

2. Device Path Parsing: Sandboxie searches for \Device\ prefix in NT path strings to extract device names (kernel.c). ↩

3. Name Extraction Logic: Device name parsing terminates at the first backslash or null character after the \Device\ prefix (kernel.c). ↩

4. Fallback Behavior: Empty device names trigger Dll_rand() for random serial number generation (kernel.c). ↩

5. Hex Parser Implementation: hex_string_to_uint8_array() function processes hex strings while skipping hyphen characters (custom.c). ↩

6. Error Handling: Invalid hex characters, odd digit counts, or parsing failures return FALSE, triggering random generation (custom.c). ↩

7. Endianness Conversion: Byte swapping is performed when swap_bytes=TRUE to match Windows little-endian DWORD format (custom.c). ↩

8. Session Persistence: map_insert() stores computed serial numbers using original hardware values as keys (kernel.c). ↩

9. Thread Safety: Critical section Kernel_DiskSN_CritSec protects concurrent access to the serial number cache (kernel.c5). ↩

10. Cache Key Strategy: Original disk serial numbers serve as map keys for consistent per-session value retrieval (kernel.c). ↩