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HackTricks - Boitatech
  • HackTricks
  • About the author
  • Getting Started in Hacking
  • Pentesting Methodology
  • External Recon Methodology
    • Github Leaked Secrets
  • Phishing Methodology
    • Clone a Website
    • Detecting Phising
    • Phishing Documents
  • Exfiltration
  • Tunneling and Port Forwarding
  • Brute Force - CheatSheet
  • Search Exploits
  • Shells
    • Shells (Linux, Windows, MSFVenom)
      • MSFVenom - CheatSheet
      • Shells - Windows
      • Shells - Linux
      • Full TTYs
  • Linux/Unix
    • Checklist - Linux Privilege Escalation
    • Linux Privilege Escalation
      • PAM - Pluggable Authentication Modules
      • SELinux
      • Logstash
      • AppArmor
      • Containerd (ctr) Privilege Escalation
      • Docker Breakout
      • electron/CEF/chromium debugger abuse
      • Escaping from Jails
      • Cisco - vmanage
      • D-Bus Enumeration & Command Injection Privilege Escalation
      • Interesting Groups - Linux PE
        • lxd/lxc Group - Privilege escalation
      • ld.so exploit example
      • Linux Capabilities
      • NFS no_root_squash/no_all_squash misconfiguration PE
      • Payloads to execute
      • RunC Privilege Escalation
      • Seccomp
      • Splunk LPE and Persistence
      • SSH Forward Agent exploitation
      • Socket Command Injection
      • Wildcards Spare tricks
    • Useful Linux Commands
      • Bypass Bash Restrictions
    • Linux Environment Variables
  • MacOS
    • MacOS Security & Privilege Escalation
      • Mac OS Architecture
      • MacOS MDM
        • Enrolling Devices in Other Organisations
      • MacOS Protocols
      • MacOS Red Teaming
      • MacOS Serial Number
      • MacOS Apps - Inspecting, debugging and Fuzzing
  • Windows
    • Checklist - Local Windows Privilege Escalation
    • Windows Local Privilege Escalation
      • AppendData/AddSubdirectory permission over service registry
      • Create MSI with WIX
      • DPAPI - Extracting Passwords
      • SeImpersonate from High To System
      • Access Tokens
      • ACLs - DACLs/SACLs/ACEs
      • Dll Hijacking
      • From High Integrity to SYSTEM with Name Pipes
      • Integrity Levels
      • JAWS
      • JuicyPotato
      • Leaked Handle Exploitation
      • MSI Wrapper
      • Named Pipe Client Impersonation
      • PowerUp
      • Privilege Escalation Abusing Tokens
      • Privilege Escalation with Autoruns
      • RottenPotato
      • Seatbelt
      • SeDebug + SeImpersonate copy token
      • Windows C Payloads
    • Active Directory Methodology
      • Abusing Active Directory ACLs/ACEs
      • AD information in printers
      • ASREPRoast
      • BloodHound
      • Constrained Delegation
      • Custom SSP
      • DCShadow
      • DCSync
      • DSRM Credentials
      • Golden Ticket
      • Kerberos Authentication
      • Kerberoast
      • MSSQL Trusted Links
      • Over Pass the Hash/Pass the Key
      • Pass the Ticket
      • Password Spraying
      • Force NTLM Privileged Authentication
      • Privileged Accounts and Token Privileges
      • Resource-based Constrained Delegation
      • Security Descriptors
      • Silver Ticket
      • Skeleton Key
      • Unconstrained Delegation
    • NTLM
      • Places to steal NTLM creds
      • PsExec/Winexec/ScExec
      • SmbExec/ScExec
      • WmicExec
      • AtExec / SchtasksExec
      • WinRM
    • Stealing Credentials
      • Credentials Protections
      • Mimikatz
    • Authentication, Credentials, UAC and EFS
    • Basic CMD for Pentesters
    • Basic PowerShell for Pentesters
      • PowerView
    • AV Bypass
  • Mobile Apps Pentesting
    • Android APK Checklist
    • Android Applications Pentesting
      • Android Applications Basics
      • Android Task Hijacking
      • ADB Commands
      • APK decompilers
      • AVD - Android Virtual Device
      • Burp Suite Configuration for Android
      • content:// protocol
      • Drozer Tutorial
        • Exploiting Content Providers
      • Exploiting a debuggeable applciation
      • Frida Tutorial
        • Frida Tutorial 1
        • Frida Tutorial 2
        • Frida Tutorial 3
        • Objection Tutorial
      • Google CTF 2018 - Shall We Play a Game?
      • Inspeckage Tutorial
      • Intent Injection
      • Make APK Accept CA Certificate
      • Manual DeObfuscation
      • React Native Application
      • Reversing Native Libraries
      • Smali - Decompiling/[Modifying]/Compiling
      • Spoofing your location in Play Store
      • Webview Attacks
    • iOS Pentesting Checklist
    • iOS Pentesting
      • Basic iOS Testing Operations
      • Burp Suite Configuration for iOS
      • Extracting Entitlements From Compiled Application
      • Frida Configuration in iOS
      • iOS App Extensions
      • iOS Basics
      • iOS Custom URI Handlers / Deeplinks / Custom Schemes
      • iOS Hooking With Objection
      • iOS Protocol Handlers
      • iOS Serialisation and Encoding
      • iOS Testing Environment
      • iOS UIActivity Sharing
      • iOS Universal Links
      • iOS UIPasteboard
      • iOS WebViews
  • Pentesting
    • Pentesting Network
      • Spoofing LLMNR, NBT-NS, mDNS/DNS and WPAD and Relay Attacks
      • Spoofing SSDP and UPnP Devices with EvilSSDP
      • Wifi Attacks
        • Evil Twin EAP-TLS
      • Pentesting IPv6
      • Nmap Summary (ESP)
      • Network Protocols Explained (ESP)
      • IDS and IPS Evasion
      • DHCPv6
    • Pentesting JDWP - Java Debug Wire Protocol
    • Pentesting Printers
      • Accounting bypass
      • Buffer Overflows
      • Credentials Disclosure / Brute-Force
      • Cross-Site Printing
      • Document Processing
      • Factory Defaults
      • File system access
      • Firmware updates
      • Memory Access
      • Physical Damage
      • Software packages
      • Transmission channel
      • Print job manipulation
      • Print Job Retention
      • Scanner and Fax
    • Pentesting SAP
    • Pentesting Kubernetes
      • Enumeration from a Pod
      • Hardening Roles/ClusterRoles
      • Pentesting Kubernetes from the outside
    • 7/tcp/udp - Pentesting Echo
    • 21 - Pentesting FTP
      • FTP Bounce attack - Scan
      • FTP Bounce - Download 2ºFTP file
    • 22 - Pentesting SSH/SFTP
    • 23 - Pentesting Telnet
    • 25,465,587 - Pentesting SMTP/s
      • SMTP - Commands
    • 43 - Pentesting WHOIS
    • 53 - Pentesting DNS
    • 69/UDP TFTP/Bittorrent-tracker
    • 79 - Pentesting Finger
    • 80,443 - Pentesting Web Methodology
      • 403 & 401 Bypasses
      • AEM - Adobe Experience Cloud
      • Apache
      • Artifactory Hacking guide
      • Buckets
        • Firebase Database
        • AWS-S3
      • CGI
      • Code Review Tools
      • Drupal
      • Flask
      • Git
      • Golang
      • GraphQL
      • H2 - Java SQL database
      • IIS - Internet Information Services
      • JBOSS
      • Jenkins
      • JIRA
      • Joomla
      • JSP
      • Laravel
      • Moodle
      • Nginx
      • PHP Tricks (SPA)
        • PHP - Useful Functions & disable_functions/open_basedir bypass
          • disable_functions bypass - php-fpm/FastCGI
          • disable_functions bypass - dl function
          • disable_functions bypass - PHP 7.0-7.4 (*nix only)
          • disable_functions bypass - Imagick <= 3.3.0 PHP >= 5.4 Exploit
          • disable_functions - PHP 5.x Shellshock Exploit
          • disable_functions - PHP 5.2.4 ionCube extension Exploit
          • disable_functions bypass - PHP <= 5.2.9 on windows
          • disable_functions bypass - PHP 5.2.4 and 5.2.5 PHP cURL
          • disable_functions bypass - PHP safe_mode bypass via proc_open() and custom environment Exploit
          • disable_functions bypass - PHP Perl Extension Safe_mode Bypass Exploit
          • disable_functions bypass - PHP 5.2.3 - Win32std ext Protections Bypass
          • disable_functions bypass - PHP 5.2 - FOpen Exploit
          • disable_functions bypass - via mem
          • disable_functions bypass - mod_cgi
          • disable_functions bypass - PHP 4 >= 4.2.0, PHP 5 pcntl_exec
      • Python
      • Special HTTP headers
      • Spring Actuators
      • Symphony
      • Tomcat
      • Uncovering CloudFlare
      • VMWare (ESX, VCenter...)
      • Web API Pentesting
      • WebDav
      • werkzeug
      • Wordpress
      • XSS to RCE Electron Desktop Apps
    • 88tcp/udp - Pentesting Kerberos
      • Harvesting tickets from Windows
      • Harvesting tickets from Linux
    • 110,995 - Pentesting POP
    • 111/TCP/UDP - Pentesting Portmapper
    • 113 - Pentesting Ident
    • 123/udp - Pentesting NTP
    • 135, 593 - Pentesting MSRPC
    • 137,138,139 - Pentesting NetBios
    • 139,445 - Pentesting SMB
    • 143,993 - Pentesting IMAP
    • 161,162,10161,10162/udp - Pentesting SNMP
      • SNMP RCE
    • 194,6667,6660-7000 - Pentesting IRC
    • 264 - Pentesting Check Point FireWall-1
    • 389, 636, 3268, 3269 - Pentesting LDAP
    • 500/udp - Pentesting IPsec/IKE VPN
    • 502 - Pentesting Modbus
    • 512 - Pentesting Rexec
    • 513 - Pentesting Rlogin
    • 514 - Pentesting Rsh
    • 515 - Pentesting Line Printer Daemon (LPD)
    • 548 - Pentesting Apple Filing Protocol (AFP)
    • 554,8554 - Pentesting RTSP
    • 623/UDP/TCP - IPMI
    • 631 - Internet Printing Protocol(IPP)
    • 873 - Pentesting Rsync
    • 1026 - Pentesting Rusersd
    • 1080 - Pentesting Socks
    • 1098/1099/1050 - Pentesting Java RMI - RMI-IIOP
    • 1433 - Pentesting MSSQL - Microsoft SQL Server
    • 1521,1522-1529 - Pentesting Oracle TNS Listener
      • Oracle Pentesting requirements installation
      • TNS Poison
      • Remote stealth pass brute force
      • Oracle RCE & more
    • 1723 - Pentesting PPTP
    • 1883 - Pentesting MQTT (Mosquitto)
    • 2049 - Pentesting NFS Service
    • 2301,2381 - Pentesting Compaq/HP Insight Manager
    • 2375, 2376 Pentesting Docker
    • 3128 - Pentesting Squid
    • 3260 - Pentesting ISCSI
    • 3299 - Pentesting SAPRouter
    • 3306 - Pentesting Mysql
    • 3389 - Pentesting RDP
    • 3632 - Pentesting distcc
    • 3690 - Pentesting Subversion (svn server)
    • 4369 - Pentesting Erlang Port Mapper Daemon (epmd)
    • 5000 - Pentesting Docker Registry
    • 5353/UDP Multicast DNS (mDNS)
    • 5432,5433 - Pentesting Postgresql
    • 5601 - Pentesting Kibana
    • 5671,5672 - Pentesting AMQP
    • 5800,5801,5900,5901 - Pentesting VNC
    • 5984,6984 - Pentesting CouchDB
    • 5985,5986 - Pentesting WinRM
    • 6000 - Pentesting X11
    • 6379 - Pentesting Redis
    • 8009 - Pentesting Apache JServ Protocol (AJP)
    • 8089 - Splunkd
    • 9000 - Pentesting FastCGI
    • 9001 - Pentesting HSQLDB
    • 9042/9160 - Pentesting Cassandra
    • 9100 - Pentesting Raw Printing (JetDirect, AppSocket, PDL-datastream)
    • 9200 - Pentesting Elasticsearch
    • 10000 - Pentesting Network Data Management Protocol (ndmp)
    • 11211 - Pentesting Memcache
    • 15672 - Pentesting RabbitMQ Management
    • 27017,27018 - Pentesting MongoDB
    • 44818/UDP/TCP - Pentesting EthernetIP
    • 47808/udp - Pentesting BACNet
    • 50030,50060,50070,50075,50090 - Pentesting Hadoop
  • Pentesting Web
    • Web Vulnerabilities Methodology
    • Reflecting Techniques - PoCs and Polygloths CheatSheet
      • Web Vulns List
    • 2FA/OTP Bypass
    • Abusing hop-by-hop headers
    • Bypass Payment Process
    • Captcha Bypass
    • Cache Poisoning and Cache Deception
    • Clickjacking
    • Client Side Template Injection (CSTI)
    • Command Injection
    • Content Security Policy (CSP) Bypass
    • Cookies Hacking
    • CORS - Misconfigurations & Bypass
    • CRLF (%0D%0A) Injection
    • Cross-site WebSocket hijacking (CSWSH)
    • CSRF (Cross Site Request Forgery)
    • Dangling Markup - HTML scriptless injection
    • Deserialization
      • NodeJS - __proto__ & prototype Pollution
      • Java JSF ViewState (.faces) Deserialization
      • Java DNS Deserialization, GadgetProbe and Java Deserialization Scanner
      • Basic Java Deserialization (ObjectInputStream, readObject)
      • CommonsCollection1 Payload - Java Transformers to Rutime exec() and Thread Sleep
      • Basic .Net deserialization (ObjectDataProvider gadget, ExpandedWrapper, and Json.Net)
      • Exploiting __VIEWSTATE knowing the secrets
      • Exploiting __VIEWSTATE without knowing the secrets
    • Domain/Subdomain takeover
    • Email Header Injection
    • File Inclusion/Path traversal
      • phar:// deserialization
    • File Upload
      • PDF Upload - XXE and CORS bypass
    • Formula Injection
    • HTTP Request Smuggling / HTTP Desync Attack
    • H2C Smuggling
    • IDOR
    • JWT Vulnerabilities (Json Web Tokens)
    • NoSQL injection
    • LDAP Injection
    • Login Bypass
      • Login bypass List
    • OAuth to Account takeover
    • Open Redirect
    • Parameter Pollution
    • PostMessage Vulnerabilities
    • Race Condition
    • Rate Limit Bypass
    • Registration Vulnerabilities
    • Regular expression Denial of Service - ReDoS
    • Reset/Forgotten Password Bypass
    • SAML Attacks
      • SAML Basics
    • Server Side Inclusion/Edge Side Inclusion Injection
    • SQL Injection
      • MSSQL Injection
      • Oracle injection
      • PostgreSQL injection
        • dblink/lo_import data exfiltration
        • PL/pgSQL Password Bruteforce
        • Network - Privesc, Port Scanner and NTLM chanllenge response disclosure
        • Big Binary Files Upload (PostgreSQL)
        • RCE with PostgreSQL Extensions
      • MySQL injection
        • Mysql SSRF
      • SQLMap - Cheetsheat
        • Second Order Injection - SQLMap
    • SSRF (Server Side Request Forgery)
    • SSTI (Server Side Template Injection)
      • EL - Expression Language
    • Reverse Tab Nabbing
    • Unicode Normalization vulnerability
    • Web Tool - WFuzz
    • XPATH injection
    • XSLT Server Side Injection (Extensible Stylesheet Languaje Transformations)
    • XXE - XEE - XML External Entity
    • XSS (Cross Site Scripting)
      • PDF Injection
      • DOM XSS
      • Server Side XSS (Dynamic PDF)
      • XSS Tools
    • XSSI (Cross-Site Script Inclusion)
    • XS-Search
  • Forensics
    • Basic Forensic Methodology
      • Baseline Monitoring
      • Anti-Forensic Techniques
      • Docker Forensics
      • Image Adquisition & Mount
      • Linux Forensics
      • Malware Analysis
      • Memory dump analysis
        • Volatility - CheatSheet
      • Partitions/File Systems/Carving
        • EXT
        • File/Data Carving & Recovery Tools
        • NTFS
      • Pcap Inspection
        • DNSCat pcap analysis
        • USB Keystrokes
        • Wifi Pcap Analysis
        • Wireshark tricks
      • Specific Software/File-Type Tricks
        • .pyc
        • Browser Artifacts
        • Desofuscation vbs (cscript.exe)
        • Local Cloud Storage
        • Office file analysis
        • PDF File analysis
        • PNG tricks
        • Video and Audio file analysis
        • ZIPs tricks
      • Windows Artifacts
        • Windows Processes
        • Interesting Windows Registry Keys
  • A.I. Exploiting
    • BRA.I.NSMASHER Presentation
      • Basic Bruteforcer
      • Basic Captcha Breaker
      • BIM Bruteforcer
      • Hybrid Malware Classifier Part 1
  • Blockchain
    • Blockchain & Crypto Currencies
  • Courses and Certifications Reviews
    • INE Courses and eLearnSecurity Certifications Reviews
  • Cloud Security
    • Cloud security review
    • AWS Security
  • Physical attacks
    • Physical Attacks
    • Escaping from KIOSKs
      • Show file extensions
  • Reversing
    • Reversing Tools & Basic Methods
      • Angr
        • Angr - Examples
      • Z3 - Satisfiability Modulo Theories (SMT)
      • Cheat Engine
      • Blobrunner
    • Common API used in Malware
    • Cryptographic/Compression Algorithms
      • Unpacking binaries
    • Word Macros
  • Exploiting
    • Linux Exploiting (Basic) (SPA)
      • Format Strings Template
      • ROP - call sys_execve
      • ROP - Leaking LIBC address
        • ROP - Leaking LIBC template
      • Bypassing Canary & PIE
      • Ret2Lib
      • Fusion
    • Exploiting Tools
      • PwnTools
    • Windows Exploiting (Basic Guide - OSCP lvl)
  • Cryptography
    • Certificates
    • Cipher Block Chaining CBC-MAC
    • Crypto CTFs Tricks
    • Electronic Code Book (ECB)
    • Hash Length Extension Attack
    • Padding Oracle
    • RC4 - Encrypt&Decrypt
  • BACKDOORS
    • Merlin
    • Empire
    • Salseo
    • ICMPsh
  • Stego
    • Stego Tricks
    • Esoteric languages
  • MISC
    • Basic Python
      • venv
      • Bypass Python sandboxes
      • Magic Methods
      • Web Requests
      • Bruteforce hash (few chars)
    • Other Big References
  • TODO
    • More Tools
    • MISC
    • Pentesting DNS
  • Burp Suite
  • Other Web Tricks
  • Interesting HTTP
  • Emails Vulnerabilities
  • Android Forensics
  • TR-069
  • 6881/udp - Pentesting BitTorrent
  • CTF Write-ups
    • challenge-0521.intigriti.io
    • Try Hack Me
      • hc0n Christmas CTF - 2019
      • Pickle Rick
  • 1911 - Pentesting fox
  • Online Platforms with API
  • Stealing Sensitive Information Disclosure from a Web
  • Post Exploitation
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On this page
  • Ext - Extended Filesystem
  • Ext Optional Features
  • Superblock
  • inodes
  • Filesystem View

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  1. Forensics
  2. Basic Forensic Methodology
  3. Partitions/File Systems/Carving

EXT

PreviousPartitions/File Systems/CarvingNextFile/Data Carving & Recovery Tools

Last updated 3 years ago

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Ext - Extended Filesystem

Ext2 is the most common filesystem 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.

All block groups in the filesystem have the same size and are stored sequentially. This allows the kernel to easily derive the location of a block group in a disk from its integer index.

Every block group contains the following pieces of information:

  • A copy of the filesystem’s superblock

  • A copy of the block group descriptors

  • A data block bitmap which is used to identify the free blocks inside the group

  • An inode bitmap, which is used to identify the free inodes inside the group

  • inode table: it consists of a series of consecutive blocks, each of which contains a predefined Figure 1 Ext2 inode number of inodes. All inodes have the same size: 128 bytes. A 1,024 byte block contains 8 inodes, while a 4,096-byte block contains 32 inodes. Note that in Ext2, there is no need to store on disk a mapping between an inode number and the corresponding block number because the latter value can be derived from the block group number and the relative position inside the inode table. For example, suppose that each block group contains 4,096 inodes and that we want to know the address on disk of inode 13,021. In this case, the inode belongs to the third block group and its disk address is stored in the 733rd entry of the corresponding inode table. As you can see, the inode number is just a key used by the Ext2 routines to retrieve the proper inode descriptor on disk quickly

  • data blocks, containing files. Any block which does not contain any meaningful information, it is said to be free.

Ext Optional Features

Features affect where the data is located, how the data is stored in inodes and some of them might supply additional metadata for analysis, therefore features are important in Ext.

Ext has optional features that your OS may or may not support, there are 3 possibilities:

  • Compatible

  • Incompatible

  • Compatible Read Only: It can be mounted but not for writing

If there are incompatible features you won't be able to mount the filesystem as the OS won't know how the access the data.

Suspected attacker might have non-standard extensions

Any utility that reads the superblock will be able to indicate the features of a Ext filesystem, but you could also use file -sL /dev/sd*

Superblock

The superblock is the first 1024 bytes from the start, it's repeated in the first block of each group and contains:

  • Block size

  • Total blocks

  • Blocks per block group

  • Reserved blocks before the first block group

  • Total inodes

  • Inodes per block group

  • Volume name

  • Last write time

  • Last mount time

  • Path where the file system was last mounted

  • Filesystem status (clean?)

It's possible to obtain this information from an Ext filesystem file using:

fsstat -o <offsetstart> /pat/to/filesystem-file.ext
#You can get the <offsetstart> with the "p" command inside fdisk

inodes

The inodes contain the list of blocks that contains the actual data of a file. If the file is big, and inode may contain pointers to other inodes that points to the blocks/more inodes containing the file data.

In Ext2 and Ext3 inodes are of size 128B, Ext4 currently uses 156B but allocates 256B on disk to allow a future expansion.

Inode structure:

Offset

Size

Name

DescriptionF

0x0

2

File Mode

File mode and type

0x2

2

UID

Lower 16 bits of owner ID

0x4

4

Size Il

Lower 32 bits of file size

0x8

4

Atime

Access time in seconds since epoch

0xC

4

Ctime

Change time in seconds since epoch

0x10

4

Mtime

Modify time in seconds since epoch

0x14

4

Dtime

Delete time in seconds since epoch

0x18

2

GID

Lower 16 bits of group ID

0x1A

2

Hlink count

Hard link count

0xC

4

Blocks Io

Lower 32 bits of block count

0x20

4

Flags

Flags

0x24

4

Union osd1

Linux: I version

0x28

69

Block[15]

15 pointes to data block

0x64

4

Version

File version for NFS

0x68

4

File ACL low

Lower 32 bits of extended attributes (ACL, etc)

0x6C

4

File size hi

Upper 32 bits of file size (ext4 only)

0x70

4

Obsolete fragment

An obsoleted fragment address

0x74

12

Osd 2

Second operating system dependent union

0x74

2

Blocks hi

Upper 16 bits of block count

0x76

2

File ACL hi

Upper 16 bits of extended attributes (ACL, etc.)

0x78

2

UID hi

Upper 16 bits of owner ID

0x7A

2

GID hi

Upper 16 bits of group ID

0x7C

2

Checksum Io

Lower 16 bits of inode checksum

"Modify" is the timestamp of the last time the file's content has been mofified. This is often called "mtime". "Change" is the timestamp of the last time the file's inode has been changed, like by changing permissions, ownership, file name, number of hard links. It's often called "ctime".

Inode structure extended (Ext4):

Offset

Size

Name

Description

0x80

2

Extra size

How many bytes beyond standard 128 are used

0x82

2

Checksum hi

Upper 16 bits of inode checksum

0x84

4

Ctime extra

Change time extra bits

0x88

4

Mtime extra

Modify time extra bits

0x8C

4

Atime extra

Access time extra bits

0x90

4

Crtime

File create time (seconds since epoch)

0x94

4

Crtime extra

File create time extra bits

0x98

4

Version hi

Upper 32 bits of version

0x9C

Unused

Reserved space for future expansions

Special inodes:

Inode

Special Purpose

0

No such inode, numberings starts at 1

1

Defective block list

2

Root directory

3

User quotas

4

Group quotas

5

Boot loader

6

Undelete directory

7

Reserved group descriptors (for resizing filesystem)

8

Journal

9

Exclude inode (for snapshots)

10

Replica inode

11

First non-reserved inode (often lost + found)

Not that the creation time only appears in Ext4.

Knowing the inode number you can easily find it's index:

  • Block group where an inode belongs: (Inode number - 1) / (Inodes per group)

  • Index inside it's group: (Inode number - 1) mod(Inodes/groups)

  • Offset into inode table: Inode number * (Inode size)

  • The "-1" is because the inode 0 is undefined (not used)

ls -ali /bin | sort -n #Get all inode numbers and sort by them
stat /bin/ls #Get the inode information of a file
istat -o <start offset> /path/to/image.ext 657103 #Get information of that inode inside the given ext file
icat -o <start offset> /path/to/image.ext 657103 #Cat the file

File Mode

Number

Description

15

Reg/Slink-13/Socket-14

14

Directory/Block Bit 13

13

Char Device/Block Bit 14

12

FIFO

11

Set UID

10

Set GID

9

Sticky Bit (without it, anyone with Write & exec perms on a directory can delete and rename files)

8

Owner Read

7

Owner Write

6

Owner Exec

5

Group Read

4

Group Write

3

Group Exec

2

Others Read

1

Others Write

0

Others Exec

The bold bits (12, 13, 14, 15) indicate the type of file the file is (a directory, socket...) only one of the options in bold may exit.

Directories

Offset

Size

Name

Description

0x0

4

Inode

0x4

2

Rec len

Record length

0x6

1

Name len

Name length

0x7

1

File type

0x00 Unknown 0x01 Regular

0x02 Director

0x03 Char device

0x04 Block device

0x05 FIFO

0x06 Socket

0x07 Sym link

0x8

Name

Name string (up to 255 characters)

In order to increase the performance, Root hash Directory blocks may be used.

Extended Attributes

Can be stored in

  • Extra space between inodes (256 - inode size, usually = 100)

  • A data block pointed to by file_acl in inode

Can be used to store anything as a users attribute if name starts with "user".

Data can ne hidden this way.

Extended Attributes Entries

Offset

Size

Name

Description

0x0

1

Name len

Length of attribute name

0x1

1

Name index

0x0 = no prefix

0x1 = user. Prefix

0x2 = system.posix_acl_access

0x3 = system.posix_acl_default

0x4 = trusted.

0x6 = security.

0x7 = system.

0x8 = system.richacl

0x2

2

Value offs

Offset from first inode entry or start of block

0x4

4

Value blocks

Disk block where value stored or zero for this block

0x8

4

Value size

Length of value

0xC

4

Hash

Hash for attribs in block or zero if in inode

0x10

Name

Attribute name w/o trailing NULL

setfattr -n 'user.secret' -v 'This is a secret' file.txt #Save a secret using extended attributes
getfattr file.txt #Get extended attribute names of a file
getdattr -n 'user.secret' file.txt #Get extended attribute called "user.secret"

Filesystem View

You can also use the free gui application: Or you can also use python to obtain the superblock information:

In order to see the contents of the file system you can use the free tool: Or you can mount it in your linux using mount command.

https://www.disk-editor.org/index.html
https://pypi.org/project/superblock/
https://www.disk-editor.org/index.html
https://piazza.com/class_profile/get_resource/il71xfllx3l16f/inz4wsb2m0w2oz#:~:text=The%20Ext2%20file%20system%20divides,lower%20average%20disk%20seek%20time.