hacktricks/forensics/basic-forensic-methodology/anti-forensic-techniques.md

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<details>
<summary><strong>Support HackTricks and get benefits!</strong></summary>
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</details>
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# Timestamps
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An attacker may be interested in **changing the timestamps of files** to avoid being detected.\
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It's possible to find the timestamps inside the MFT in attributes `$STANDARD_INFORMATION` __ and __ `$FILE_NAME`.
Both attributes have 4 timestamps: **Modification**, **access**, **creation**, and **MFT registry modification** (MACE or MACB).
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**Windows explorer** and other tools show the information from **`$STANDARD_INFORMATION`**.
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## TimeStomp - Anti-forensic Tool
This tool **modifies** the timestamp information inside **`$STANDARD_INFORMATION`** **but** **not** the information inside **`$FILE_NAME`**. Therefore, it's possible to **identify** **suspicious** **activity**.
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## Usnjrnl
The **USN Journal** (Update Sequence Number Journal), or Change Journal, is a feature of the Windows NT file system (NTFS) which **maintains a record of changes made to the volume**.\
It's possible to use the tool [**UsnJrnl2Csv**](https://github.com/jschicht/UsnJrnl2Csv) to search for modifications of this record.
![](<../../.gitbook/assets/image (449).png>)
The previous image is the **output** shown by the **tool** where it can be observed that some **changes were performed** to the file.
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## $LogFile
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All metadata changes to a file system are logged to ensure the consistent recovery of critical file system structures after a system crash. This is called [write-ahead logging](https://en.wikipedia.org/wiki/Write-ahead\_logging).\
The logged metadata is stored in a file called “**$LogFile**”, which is found in a root directory of an NTFS file system.\
It's possible to use tools like [LogFileParser](https://github.com/jschicht/LogFileParser) to parse this file and find changes.
![](<../../.gitbook/assets/image (450).png>)
Again, in the output of the tool it's possible to see that **some changes were performed**.
Using the same tool it's possible to identify to **which time the timestamps were modified**:
![](<../../.gitbook/assets/image (451).png>)
* CTIME: File's creation time
* ATIME: File's modification time
* MTIME: File's MFT registry modifiction
* RTIME: File's access time
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## `$STANDARD_INFORMATION` and `$FILE_NAME` comparison
Another way to identify suspicions modified files would be to compare the time on both attributes looking for **mismatches**.
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## Nanoseconds
**NTFS** timestamps have a **precision** of **100 nanoseconds**. Then, finding files with timestamps like 2010-10-10 10:10:**00.000:0000 is very suspicious**.
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## SetMace - Anti-forensic Tool
This tool can modify both attributes `$STARNDAR_INFORMATION` and `$FILE_NAME` . However, from Windows Vista it's necessary a live OS to modify this information.
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# Data Hiding
NFTS uses a cluster and the minimum information size. That means that if a file occupies uses and cluster and a half, the **reminding half is never going to be used** until the files is deleted. Then, it's possible to **hide data in this slack space**.
There are tools like slacker that allows to hide data in this "hidden" space. However, an analysis of the `$logfile` and `$usnjrnl` can show that some data was added:
![](<../../.gitbook/assets/image (452).png>)
Then, it's possible to retrieve the slack space using tools like FTK Imager. Note that this can of tools can save the content obfuscated or even encrypted.
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# UsbKill
This is a tool that will **turn off the computer is any change in the USB** ports is detected.\
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A way to discover this would be to inspect the running processes and **review each python script running**.
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# Live Linux Distributions
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These distros are **executed inside the RAM** memory. The only way to detect them is **in case the NTFS file-system is mounted with write permissions**. If it's mounted just with read permissions it won't be possible to detect the intrusion.
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# Secure Deletion
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[https://github.com/Claudio-C/awesome-data-sanitization](https://github.com/Claudio-C/awesome-data-sanitization)
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# Windows Configuration
It's possible to disable several windows logging methods to make the forensics investigation much harder.
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## Disable Timestamps - UserAssist
This is a registry key that maintains dates and hours when each executable was run by the user.
Disabling UserAssist requires two steps:
1. Set two registry keys, `HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Start_TrackProgs` and `HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Start_TrackEnabled`, both to zero in order to signal that we want UserAssist disabled.
2. Clear your registry subtrees that look like `HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\UserAssist\<hash>`.
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## Disable Timestamps - Prefetch
This will save information about the applications executed with the goal of improving the performance of the Windows system. However, this can also be useful for forensics practices.
* Rexecute `regedit`
* Select the file path `HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SessionManager\Memory Management\PrefetchParameters`
* Right-click on both `EnablePrefetcher` and `EnableSuperfetch`
* Select Modify on each of these to change the value from 1 (or 3) to 0
* Restart
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## Disable Timestamps - Last Access Time
Whenever a folder is opened from an NTFS volume on a Windows NT server, the system takes the time to **update a timestamp field on each listed folder**, called the last access time. On a heavily used NTFS volume, this can affect performance.
1. Open the Registry Editor (Regedit.exe).
2. Browse to `HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem`.
3. Look for `NtfsDisableLastAccessUpdate`. If it doesnt exist, add this DWORD and set its value to 1, which will disable the process.
4. Close the Registry Editor, and reboot the server.
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## Delete USB History
All the **USB Device Entries** are stored in Windows Registry Under **USBSTOR** registry key that contains sub keys which are created whenever you plug a USB Device in your PC or Laptop. You can find this key here H`KEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USBSTOR`. **Deleting this** you will delete the USB history.\
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You may also use the tool [**USBDeview**](https://www.nirsoft.net/utils/usb\_devices\_view.html) to be sure you have deleted them (and to delete them).
Another file that saves information about the USBs is the file `setupapi.dev.log` inside `C:\Windows\INF`. This should also be deleted.
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## Disable Shadow Copies
**List** shadow copies with `vssadmin list shadowstorage`\
**Delete** them running `vssadmin delete shadow`
You can also delete them via GUI following the steps proposed in [https://www.ubackup.com/windows-10/how-to-delete-shadow-copies-windows-10-5740.html](https://www.ubackup.com/windows-10/how-to-delete-shadow-copies-windows-10-5740.html)
To disable shadow copies:
1. Go to the Windows start button and type "services" into the text search box; open the Services program.
2. Locate "Volume Shadow Copy" from the list, highlight it, and then and the right-click > Properties.
3. From the "Startup type" drop-down menu, select Disabled, and then click Apply and OK.
![](<../../.gitbook/assets/image (453).png>)
It's also possible to modify the configuration of which files are going to be copied in the shadow copy in the registry `HKLM\SYSTEM\CurrentControlSet\Control\BackupRestore\FilesNotToSnapshot`
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## Overwrite deleted files
* You can use a **Windows tool**: `cipher /w:C` This will indicate cipher to remove any data from the available unused disk space inside the C drive.
* You can also use tools like [**Eraser**](https://eraser.heidi.ie)
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## Delete Windows event logs
* Windows + R --> eventvwr.msc --> Expand "Windows Logs" --> Right click each category and select "Clear Log"
* `for /F "tokens=*" %1 in ('wevtutil.exe el') DO wevtutil.exe cl "%1"`
* `Get-EventLog -LogName * | ForEach { Clear-EventLog $_.Log }`
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## Disable Windows event logs
* `reg add 'HKLM\SYSTEM\CurrentControlSet\Services\eventlog' /v Start /t REG_DWORD /d 4 /f`
* Inside the services section disable the service "Windows Event Log"
* `WEvtUtil.exec clear-log` or `WEvtUtil.exe cl`
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## Disable $UsnJrnl
* `fsutil usn deletejournal /d c:`
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2022-05-01 16:32:23 +00:00
2022-04-28 16:01:33 +00:00
<details>
<summary><strong>Support HackTricks and get benefits!</strong></summary>
Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
**Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**
**Share your hacking tricks submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**
</details>
2022-05-01 16:32:23 +00:00