nemozone

Download pre-installed Windows virtual machines

January 29, 2023

For those looking to download pre-installed Windows virtual machines for Oracle VirtualBox, Microsoft provides VHD/VHDX files of their Operating Systems. These files are compatible with Oracle VirtualBox and can be downloaded from the Microsoft developer website. Once the download is complete, users can import the VM to VirtualBox and use it easily. It is important to note that Microsoft Operating Systems need to be activated to use in the long term, and usually these images can be used for six months without activation.

For Linux distributions, OSBoxes and Linuxvmimages are two popular websites where users can get most, if not all, distributions available as VirtualBox images. All the open-source VDI images are free and will remain free. After downloading the VDI file, users can attach it to VirtualBox as an Operating System hard disk to use instantly. It is important to check the ‘Read Me’ section of each OS that has the basic requirement and username/password.

In addition, VMware Workstation Player is a completely free-to-use version of its desktop VM software, Workstation Pro. This is a great option for those looking for a free virtual machine.

Citations :

ExifTool

January 29, 2023

ExifTool is a powerful and versatile tool for reading, writing, and manipulating image, audio, video, and PDF metadata. It is available as both a Perl library (Image::ExifTool) and command-line application, and is platform independent. It can be used on Ubuntu 22.04 LTS Jammy Jellyfish to read, modify, and manipulate metadata of images, audio, video, and PDF files.

To install ExifTool on Ubuntu 22.04, first make sure that all system packages are up-to-date by running the following apt commands in the terminal:

sudo apt-get update && sudo apt-get upgrade

Then, execute the command

sudo apt install exiftool -y to install ExifTool

from the Ubuntu 22.04 repository.

Once installed, some basic commands to use ExifTool include extracting information from a file (exiftool a.jpg), adding an IPTC keyword in a pipeline (cat a.jpg | exiftool -iptc:keywords+=fantastic – > b.jpg), and setting ExifTool API options (-api OPT[=VAL]). Advanced options allow complex processing to be performed from a single command without the need for additional scripting.

The -args option outputs information in the form of exiftool arguments, suitable for use with the –@ option when writing. The -b option outputs requested metadata in binary format without tag names or descriptions, and the -c FMT option sets the print format for GPS coordinates.

ExifTool exits with a status of 0 on success, or 1 if an error occurred or if all files failed the -if condition. It is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

Here are some practical CLI examples for removing metadata from an image using ExifTool:

Remove all metadata:

exiftool -all= image.jpg

Remove specific metadata tags:

exiftool -xmp:Subject= -xmp:Creator= -xmp:Author= image.jpg

Remove metadata from multiple images:

exiftool -all= *.jpg

Remove metadata and create a backup of the original image:

exiftool -all= -o .bak image.jpg

Note: The -all= option removes all metadata from the image and the -o .bak option creates a backup of the original image with the extension .bak.

Citations :

Secure Boot in Linux: Risks and Benefits of Adopting this Anti-Malware Feature

January 29, 2023

Secure Boot is a security feature that can help protect systems from malware by only allowing signed software to run. However, most Linux Distros do not support SecureBoot and require extended work by the user or developers to work. This is because the Linux bootloader is not digitally signed with one of the certificates stored in the BIOS. There are a few Linux distros that have a signed bootloader, but this is not common.

Another approach to UEFI secure boot is Trusted Boot (tboot), which utilizes a Trusted Platform Module (TPM) instead of signatures. The TPM is a cryptographic coprocessor that can be used for secure storage, RNG, system state reporting, and more. Unlike Secure Boot, tboot does not use signatures and does not directly stop the boot sequence. Instead, it puts the machine into a privileged and trusted state, where it can then take measurements of the OS and related components and push them to the TPM to be stored securely.

Secure Boot is useful for Linux, as it can help protect the system from rootkits and other attacks that may not be detected by antivirus software. However, there are some disadvantages to using Secure Boot. For example, signing authorities may make mistakes in granting signatures or loading hashes, and bootloaders that ignore Secure Boot and boot-time malware have been mistakenly signed and released to the public in the past. Additionally, there is an element of implicit trust when using tboot/TPM, as it delves into a stratum of hardware and processor microcode that is not completely explained.

Overall, nobody uses Secure Boot on their installed Linux systems because it requires extra work to get it working, and there are some potential risks associated with it.

Some editorial notes:

There are in fact some Linux Distributions which provide accessible support for secure boot. Nonetheless, it is not a silver bullet or a magic wand and can still be subjugated The DRM like nature and hindrance of creative work or experimenting is still a big flaw The overall additional steps and maintenance work to keep a system working is also a big downer There are a handful of people organizations, primarily government or big-tech sided, which indeed elaborately – extensively use this technology. Citations :

Free Online OCR Services for Digitizing Text Documents

January 29, 2023

Optical Character Recognition (OCR) is a technology that enables users to convert scanned images of text documents into editable files. OCR software can be used to digitize paper documents, save time required for manual data entry, improve information accessibility for users, and speed up the document workflow process. There are several free online OCR services available, such as OnlineOCR, Convertio, NewOCR, and OCR.Space.To use these services, users must first upload an image or PDF file in JPG, BMP, GIF, TIFF, or PDF format. Then, they must select a language of the file and choose an output format from Word, Excel, and TXT. Finally, they must click “Convert” to start recognizing and converting their files.OnlineOCR is a professional online OCR service with a clean and simple design. It is able to keep all the layouts, formatting, tables, columns and graphics from the original file to the converted document. Convertio is a free online OCR service with a modern and pretty design. NewOCR is another free online OCR service that can analyze the text in the image or PDF uploaded and then convert it to a text document. OCR.Space offers multiple options for text recognition, such as auto-rotating images and creating a searchable PDF with a visible or invisible text layer.Overall, these free online OCR services are not perfect but can cover most of users' OCR requirements. Both OnlineOCR and Convertio perform very well among competitors and should be users' first choice when they need a free OCR online, especially for scanned PDF OCR online.

Citations :

Here is a good page for this:

https://www.onlineocr.net/ https://www.ocr.best

Samsung LU28E590DS/Eti: A High Glossy 28-inch Ultra HD Monitor with Impressive Picture Quality

January 29, 2023

The Samsung LU28E590DS/Eti model is a 28-inch Ultra HD monitor with a high glossy black finish. It has a TN panel that offers an impressive picture quality and 1ms response time. However, it does not have HDR capabilities. Additionally, this model does not come with speakers.In terms of compatibility, the Samsung LU28E590DS/Eti model is compatible with Ubuntu 22.04 and PopOS. According to the official Samsung website, this model is compatible with Windows 10, 8.1, 8, 7, Vista, XP, Mac OS X 10.6 or later, and Linux. Therefore, it should be compatible with both Ubuntu 22.04 and PopOS.

The Color Display Unit Model Code LU28E590DS/Eti is a monitor manufactured by Samsung Electronics (UK) Ltd. It was made in China and has a version number of ISSO7. It is a 28-inch wide-screen LCD monitor with a 3D-LUT, which takes the LUT concept even further. This monitor features a 3D-LUT, which allows for smoother tonal transitions and better representation of tones in shadow areas. It also has an LUT table with eight bits per RGB color and employs internal calculations at 10 or more bits to map input signals to output signals. This monitor is ideal for applications that require high-fidelity color reproduction, as well as for ordinary PC users seeking better picture quality.

Despite being allegedly compatible with Linux. A current very cutting-edge notebook hardware test with the latest Ubuntu 22.04 and most current kernel resulted in a non-functioning HDMI port. Probably there are some EDID issues. One can alternatively use the DisplayPort.

Citations :

Impact of LUKS Encryption on NVMe SSD Performance: A Deep Dive

January 29, 2023

Using LUKS encryption on a 512 GB NVMe SSD can result in a significant performance drop. According to tests, the read speed of an unencrypted drive can be around 1700 MB/s, while the same drive with LUKS encryption can have a read speed of around 1300 MB/s, resulting in a 24% decrease in performance. The write speed of an unencrypted drive can be around 3200 MB/s, while the same drive with LUKS encryption can have a write speed of around 1100 MB/s, resulting in a 66% decrease in performance.

The performance drop is due to the CPU and RAM not being able to handle the data rates required to (de/en)crypt it on the fly. This is because every block that is read or written needs to be encrypted or decrypted, which adds a small amount of CPU load.

By default, LUKS uses a highly secure 512-bit AES (Advanced Encryption Standard) key. This provides a strong level of encryption, but also requires more resources to process the data. To reduce the performance hit, users can experiment with different algorithms and settings to find the best balance between security and performance.

Citations :

Blurring Information with GIMP: A Step-by-Step Guide

January 29, 2023

Using GIMP to blur information is a simple process. To begin, open the image you want to blur in GIMP and select the Blur/Sharpen tool from the Tools menu. You can also call the tool by clicking the tool icon in the Toolbox or by using the keyboard shortcut Shift+U. Once the tool is selected, you can adjust the settings for the type of blur that you are applying. The normal Blur effect only softens the selection, but can be applied multiple times for a stronger effect; the Gaussian blur enables you to adjust the horizontal and vertical blur radius for a very blurry effect; the Motion blur enables you to adjust the blur length and angle to create the impression of movement; and the Pixelize blur enables you to adjust the pixel width and height of the selection to create a pixelated blur distortion.

Once you have adjusted the settings, click and drag your mouse cursor over the part of the image you want to blur. You can apply different blur effects to different things in your image, such as applying a Pixelize blur to a face and a Gaussian blur to an offensive slogan. After you are satisfied with the preview, click “OK” to apply the blur effect to the selection in the image. If you need to make more things blurry, use one of the selection tools to select another area of the image and repeat the process.

For a more intense blur effect, you can also use the Gaussian Blur Overlays technique. To do this, create a duplicate layer in the image, lighten it and blur it, and combine it using a layer mode with the original. Select the Blur Overlay layer in the Layers dialog and select “Overlay” in the “Mode” drop-down box. Then go back to the image window and apply a Levels or Curves and adjust it until the overall image has the proper brightness. Finally, go back to the image window and select Filters –> Blur –> Gaussian Blur and adjust the value until you get the desired effect.

Well, if you have very sensitive information, don't use blur. Just saying.

Citations :

Masking and anonymize information with a bar in GIMP

January 29, 2023

Masking is a useful tool in GIMP that can be used to hide parts of an image. To add an alpha channel in GIMP, you can access the command from the image menubar through Layer → Transparency → Add Alpha Channel. Alternatively, you can access it through Add Alpha Channel of its context pop-up menu at the Layer Dialog. To censor in GIMP, select an area you wish to be censored using select tool. Then go to menubar Filters > Blur > Pixelize > OK. You can repeat censoring by pressing Ctrl+F to make censored area more unclear. Unselect by pressing Ctrl+Shift+A.

To anonymize information with a bar in GIMP, you can use the masking effect. First, open GIMP and load the image with the objects that you want to blur. Then click the selection tool from the GIMP Toolbox that is best suited for selecting the things in your image that you want to blur. For example, use the Rectangle Select tool for signs, the Ellipse Select tool for faces or the Free Select tool for things that have irregular shapes. Click and drag your mouse cursor over the part of the image you want to blur. Finally, go to menubar Filters > Blur > Pixelize > OK. This will create a blurred bar over the selected area, effectively anonymizing the information.

Citations :

Correct Data Deletion of Flash Memory | SSDs | NVMe Drives

January 29, 2023

When it comes to securely deleting a file on flash memory, such as a USB stick or SSD, it is essential to take into account the internal control electronics that ensures that different memory cells are used for each write operation. Consequently, using tools such as “shred” or “wipe” to overwrite individual files is not effective. Additionally, flash memory also has reserve cells that cannot be overwritten by erasing the entire device.

On Linux systems, the “hdparm” command line tool can be used to erase an SSD or flash memory. However, it's important to note that a secure erase via this method cannot be guaranteed 100%. A more secure solution would be to use operating system-side disk encryption, such as dm-crypt/LUKS, instead of relying on the firmware option of the flash memory.

To use “hdparm” to erase data on an SSD or flash memory, the following steps can be taken:

Check the device information with the command “hdparm -I /dev/sdX“

(replace X with the drive letter)

Set a temporary password for the device with the command “hdparm --user-master u --security-set-pass password123 /dev/sdX“

(replace password123 with your desired password)

Verify the operation was successful by running the command “hdparm -I /dev/sdX” again

Start the deletion process with the command “hdparm --user-master u --security-erase password123 /dev/sdX“

(replace password123 with the set password)

How to Securely Erase Data from a USB Stick using F3 – Fight Flash Fraud on Ubuntu 22.04

F3 – Fight Flash Fraud is a free and open-source tool designed for checking and wiping USB sticks on Ubuntu. This tool enables you to securely erase all data from your USB stick, especially useful when disposing of or selling the device. In this article, we will guide you through the process of installing and using F3 on Ubuntu 22.04.

Step 1: Installing F3

Open the terminal and enter the following command to install F3:

sudo apt update && sudo apt-get install f3

Step 2: Identifying the USB Stick

Before erasing data from the USB stick, you need to identify the device name. To do this, insert the USB stick into your computer and enter the following command in the terminal:

lsblk

The output will display a list of all connected storage devices and their names. Look for the device that corresponds to your USB stick (e.g. /dev/sdb).

Step 3: Erasing the Data

Once you have identified the device name, enter the following command to securely erase the data on the USB stick:

sudo f3write /dev/sdb

Note: Replace “/dev/sdb” with the actual device name of your USB stick.

This command will erase all data on the device and overwrite it with random data. The erasure process may take some time, depending on the size of the device.

Step 4: Verifying the Erasure

After the erasure process is complete, you can verify that the data has been erased by entering the following command:

sudo f3read /dev/sdb

This will run a read test on the device and report any errors. If no errors are found, the data has been securely erased.

Conclusion

F3 - Fight Flash Fraud is an effective tool for securely erasing data from your USB stick on Ubuntu. With these simple steps, you can ensure that all sensitive information is deleted before disposing of or selling the device.

It's important to note that wiping data using F3 - Fight Flash Fraud is not a 100% guarantee that the data has been completely erased. Although the tool overwrites the data on the device, it is still possible for a determined attacker to recover some of the original information.

For maximum security, it is recommended to use encryption. One method of encrypting a USB stick is dm-crypt LUKS. dm-crypt LUKS is a disk encryption method that provides strong security for stored data. With LUKS, the data on the USB stick is encrypted using a password or key, making it difficult for anyone to access the data without the password or key.

To encrypt a USB stick using dm-crypt LUKS, follow these steps:

Create a LUKS-encrypted partition on the USB stick. Format the encrypted partition with a filesystem (e.g. ext4). Mount the encrypted partition to a directory. Copy the data you want to store on the USB stick to the mounted directory. Unmount the encrypted partition. Encrypting the data on your USB stick with dm-crypt LUKS ensures that your data is protected even if the device falls into the wrong hands. Gparted can be used to accomplish this encryption process.

Thx to @macst3r <3

NVMe drives

For NVMe drives, it's recommended to use NVMe CLI tools as they are specifically designed for the NVMe specification and offer greater functionality. Data on an NVMe drive can be securely deleted using the “nvme-format" tool. The general process is as follows:

Check for NVMe devices on the system with the command “nvme list“ Format the NVMe device with the command “sudo nvme format -s1 /dev/nvme0n1“

Confirm the format command.

It's important to note that while data deletion on an NVMe drive can be secured, it still cannot be guaranteed 100%. Physical destruction of the device may be necessary.

To install “nvme-cli” on Ubuntu 22.04, the following steps can be taken:

Update the package lists with the command “sudo apt-get update“ Install the “nvme-cli” package with the command “sudo apt-get install nvme-cli“ Verify the installation was successful by displaying the version of the “nvme-cli” tool with the command “nvme version“

With these steps completed, you should now be able to use “nvme-cli” on Ubuntu 22.04.

This blog post was inspired by:

https://www.kuketz-blog.de/ssd-flashspeicher-sicher-loeschen/

Further reading, citations sorry some sources are in german:

https://computertruhe.de/2020/08/09/integritaetspruefung-und-sichere-datenloeschung-von-flash-speichern-mit-f3-und-h2testw/

https://www.anleitungen.rrze.fau.de/betriebssysteme/linux/datentraeger-sicher-loeschen-und-entsorgen/sata-datentraeger-sicher-loeschen/

https://www.awxcnx.de/handbuch_42.htm

https://paderta.com/privacy/daten-sicher-loschen/

https://www.usenix.org/legacy/events/fast11/tech/full_papers/Wei.pdf

https://docplayer.org/81314583-Daten-von-festplatten-ssds-und-handys-sicher-loeschen.html

https://linuxundich.de/gnu-linux/usb-sticks-und-sd-karten-auf-fehler-pruefen/comment-page-1/

https://maker-tutorials.com/osx-el-capitan-freien-speicherplatz-sicher-loeschenueberschreiben/

https://wiki.debianforum.de/Hdparm

https://www.edv-buchversand.de/productinfo.php?replace=false&cnt=productinfo&mode=2&type=2&id=gp-1765&index=2&nr=0&sid=b4e1637ab535b196916bfb07f02a1660&preload=false&page=1&view=fit&Toolbar=1&pagemode=none

https://www.kingston.com/de/blog/personal-storage/using-usb-drive-on-mac

https://blog.idgard.com/de/so-unsicher-sind-usb-sticks/

https://github.com/AltraMayor/f3

How to query AMD P-state from Fedora via terminal?

January 29, 2023

To query the P-state (performance state) of an AMD processor on a Fedora system using the terminal, you can use the cpupower command. The cpupower command is a tool that can be used to set and query various settings related to CPU power management, including P-states.

To query the current P-state of your processor, you can use the following command:

cpupower frequency-info

This command will display information about the current P-state, including the current frequency, the available frequencies, and the governor (the algorithm used to control the P-state).

You can also use the command

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq

This will give you the current frequency of your CPU

Alternatively you can use

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

To install the cpupower tool on a Fedora system, you can use the dnf package manager.

First, open a terminal window.

Then, run the following command as root or with sudo:

dnf install cpupower

This command will install the cpupower package and its dependencies on your system.

Once the installation is complete, you can use the cpupower command as described above to query and set various settings related to CPU power management.

Alternatively, you can use the command

yum install cpupower

if you are using an older version of Fedora that uses yum package manager instead of dnf.