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It's allocated in the **first sector of the disk after the 446B of the boot code**. This sector is essential to indicate to the PC what and from where a partition should be mounted.\
It allows up to **4 partitions** (at most **just 1** can be active/**bootable**). However, if you need more partitions you can use **extended partitions**. The **final byte** of this first sector is the boot record signature **0x55AA**. Only one partition can be marked as active.\
From the **bytes 440 to the 443** of the MBR you can find the **Windows Disk Signature** (if Windows is used). The logical drive letter of the hard disk depends on the Windows Disk Signature. Changing this signature could prevent Windows from booting (tool: [**Active Disk Editor**](https://www.disk-editor.org/index.html)**)**.
**Logical block addressing** (**LBA**) is a common scheme used for **specifying the location of blocks** of data stored on computer storage devices, generally secondary storage systems such as hard disk drives. LBA is a particularly simple linear addressing scheme; **blocks are located by an integer index**, with the first block being LBA 0, the second LBA 1, and so on.
The GUID Partition Table, known as GPT, is favored for its enhanced capabilities compared to MBR (Master Boot Record). Distinctive for its **globally unique identifier** for partitions, GPT stands out in several ways:
* **Redundancy**: Unlike MBR, GPT doesn't confine partitioning and boot data to a single place. It replicates this data across the disk, enhancing data integrity and resilience.
* **Cyclic Redundancy Check (CRC)**: GPT employs CRC to ensure data integrity. It actively monitors for data corruption, and when detected, GPT attempts to recover the corrupted data from another disk location.
* GPT maintains backward compatibility through a protective MBR. This feature resides in the legacy MBR space but is designed to prevent older MBR-based utilities from mistakenly overwriting GPT disks, hence safeguarding the data integrity on GPT-formatted disks.
In operating systems that support **GPT-based boot through BIOS** services rather than EFI, the first sector may also still be used to store the first stage of the **bootloader** code, but **modified** to recognize **GPT****partitions**. The bootloader in the MBR must not assume a sector size of 512 bytes.
The partition table header defines the usable blocks on the disk. It also defines the number and size of the partition entries that make up the partition table (offsets 80 and 84 in the table).
| 12 (0x0C) | 4 bytes | Header size in little endian (in bytes, usually 5Ch 00h 00h 00h or 92 bytes) |
| 16 (0x10) | 4 bytes | [CRC32](https://en.wikipedia.org/wiki/CRC32) of header (offset +0 up to header size) in little endian, with this field zeroed during calculation |
| 20 (0x14) | 4 bytes | Reserved; must be zero |
| 24 (0x18) | 8 bytes | Current LBA (location of this header copy) |
| 32 (0x20) | 8 bytes | Backup LBA (location of the other header copy) |
| 40 (0x28) | 8 bytes | First usable LBA for partitions (primary partition table last LBA + 1) |
| 48 (0x30) | 8 bytes | Last usable LBA (secondary partition table first LBA − 1) |
| 56 (0x38) | 16 bytes | Disk GUID in mixed endian |
| 80 (0x50) | 4 bytes | Number of partition entries in array |
| 84 (0x54) | 4 bytes | Size of a single partition entry (usually 80h or 128) |
| 88 (0x58) | 4 bytes | CRC32 of partition entries array in little endian |
| 92 (0x5C) | \* | Reserved; must be zeroes for the rest of the block (420 bytes for a sector size of 512 bytes; but can be more with larger sector sizes) |
After mounting the forensics image with [**ArsenalImageMounter**](https://arsenalrecon.com/downloads/), you can inspect the first sector using the Windows tool [**Active Disk Editor**](https://www.disk-editor.org/index.html)**.** In the following image an **MBR** was detected on the **sector 0** and interpreted:
The **FAT (File Allocation Table)** file system is designed around its core component, the file allocation table, positioned at the volume's start. This system safeguards data by maintaining **two copies** of the table, ensuring data integrity even if one is corrupted. The table, along with the root folder, must be in a **fixed location**, crucial for the system's startup process.
**Ext2** is the most common file system for **not journaling** partitions (**partitions that don't change much**) like the boot partition. **Ext3/4** are **journaling** and are used usually for the **rest partitions**.
Some files contain metadata. This information is about the content of the file which sometimes might be interesting to an analyst as depending on the file type, it might have information like:
You can use tools like [**exiftool**](https://exiftool.org) and [**Metadiver**](https://www.easymetadata.com/metadiver-2/) to get the metadata of a file.
As was seen before there are several places where the file is still saved after it was "deleted". This is because usually the deletion of a file from a file system just marks it as deleted but the data isn't touched. Then, it's possible to inspect the registries of the files (like the MFT) and find the deleted files.
Also, the OS usually saves a lot of information about file system changes and backups, so it's possible to try to use them to recover the file or as much information as possible.
**File carving** is a technique that tries to **find files in the bulk of data**. There are 3 main ways tools like this work: **Based on file types headers and footers**, based on file types **structures** and based on the **content** itself.
Note that this technique **doesn't work to retrieve fragmented files**. If a file **isn't stored in contiguous sectors**, then this technique won't be able to find it or at least part of it.
Obviously, there are ways to **"securely" delete files and part of logs about them**. For example, it's possible to **overwrite the content** of a file with junk data several times, and then **remove** the **logs** from the **$MFT** and **$LOGFILE** about the file, and **remove the Volume Shadow Copies**.\
You may notice that even performing that action there might be **other parts where the existence of the file is still logged**, and that's true and part of the forensics professional job is to find them.
<summary><strong>Learn AWS hacking from zero to hero with</strong><ahref="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
