Ubuntu Download Secure-delete
Loruhama Powe
This is the first port of call to wipe your drive. It may help to run similar tools such as shrub, secure-delete and nwipe. They all work in the same way with very similar commands and slightly different methods and patterns. Go to the Linux man page or Google them to quickly become familiar with how to use the commands. It is not likely you will need more than the standard 4 shred passes, but if it is important you might as well go the extra mile as it could possibly help.
Your RAM may well have data on it. After installing secure-delete, run the command for sdmem. This will wipe your RAM memory. However the first data you ever filled the RAM with, plus any data that stayed in RAM for prolonged periods, may well have left a trace.
Shred old data files for the same reason you shred old paper documents. We tell you what you need to know about securely deleting Linux files. This tutorial covers the shred command and the secure-delete suite of utilities.
The secure-delete commands try to overcome the best efforts of journaling filesystems and to succeed in overwriting the file securely. But exactly the same caveats apply. There is still no guarantee that the overwriting is actually taking place over the region of the hard drive that you need it to obliterate the file of interest. There's more chance, but no guarantee.
sfill is a part of secure-deletetion toolkit, is a secure free disk and inode space wiper, it deletes files on free disk space in a secure method. sfill checks the the free space on the specified partition and fills it with random data from /dev/urandom.
Note: These following two tools (sswap and sdmem) in the secure-deletetion toolkit are not directly relevant for the scope of this guide, however, we will explain them for knowledge purpose and future use.
So...when you know you have to get rid of a file, so that it can never be recovered, what do you do? Well, in Linux you have a number of options. One of those options is secure-delete. This tool is quite handy in that it can securely remove files, folders, and even securely clean free space on your drive. In this article I am going to show you how to install and use secure-delete.
Let's say you have a file in your home directory (/) called secret_stuff.txt. To delete this with secure-delete you would use the srm command (secure remove). To do that you would issue the command like so:
That file is now VERY gone. Don't expect the removal of he file to be as fast as it would with the rm command. Why does it take longer? When you issue the srm command on a file, secure-delete does the following:
Using the secure-delete tools is a sure-fire way to permanently and irrevocably remove data from a drive. This tool is so powerful even forensics teams would have trouble extracting data from the drive. Just make sure you use this tool with caution, so you do not securely delete files you actually want to keep!
I am not a fan if the cryptic command line techniques, impractical and too complex to remember and therefore unusable. I have found it handy to be able to have a secure-delete function accessible by highlighting the specific file and doing a mouse right click and hey presto it be gone.
Sponsored Link(adsbygoogle = window.adsbygoogle []).push();Deleting a file or reformatting a disk does not destroy your sensitive data. The data can easily be undeleted. That's a good thing if you accidentally throw something away, but what if your trying to destroy financial data, bank account passwords, or classified company information. In this article you will learn number of tools to delete files securely in ubuntu Linux
1) Shred
[1] I know this site is specifically about Ubuntu, but wiping data and changing settings in Nautilus are two different an unrelated things. Well, and while I indeed do use Ubuntu from time to time, I only use the server edition and Kubuntu, no Nautilus at all.
Hey everyone, I wanted to post a new thread dedicated for secure wiping SSD/HDDs after I tried hdparm and nvme-cli. I wasn't willing to share it initially, since it maybe dangerous if used incorrectly! Anyway, I posted this guide after searching many sources and made it as simple as possible! I've linked the sources at the end of the post. For images, I'm using Imgur so if anyone has any issues with images not loading or staying blank, please let me know!
I must warn everyone that incorrect name for example /dev/sdX can wipe out other drives, so backup.. backup... so as to prevent data loss. Don't hold me responsible for lost data.
For newbies, I'd recommend using Ubuntu ISO( I used Xubuntu distro) since it includes all necessary packages without needing to download anything from repos. For people who use other distros Gnome disk utility,gparted and nvme-cli packages are recommended to be installed for ease of use.
Don't forget to Backup your data before proceeding.
1. Open Gnome disk utility aka Disks and see the Disk name sdX you want to erase. My SSD is sdb, so I'm using /dev/sdb and yours might be different.
First of all, zero the space in the guest. You can do that easily with secure-delete. In the Ubuntu guest, this srm command will recursively delete all files and folders, quickly, verbosely, zero the old file and will only do it with one pass.
The problem is that the vmdk doesn't shrink. After removing 8GB of data the guest filesystem amounts to 4GB of data however the size of the vmdk is still 16GB (the same as it was at its highest). I repeatedly tried the "compact" and "defragment" VM tools (in the host OS) but size didn't change. Then I found out about vmware-tools utility in the guest OS (ubuntu), but "shrink" function is not available since I use ext4. I don't understand the essences of "journaling file systems" but it seems that there exists this limitation.
Then I took a different approach. Since there was no way to reclaim the unused virtual disk space, I tried to wipe it using "sfill" utility from the secure-delete ubuntu package. I was expecting - since the actual filesystem data i have is 4GB - that wiping the free space would work towards a smaller resulting zip file - since there is a lot of redundancy with the free space zeroed. No luck: same 10GB resulting zip file.
Yet another thing surprised me during the wiping process. Wiping works by writing a huge file with zeroes in it. Since my vmdk is not pre-allocated I was aware that I needed to stop the wiping at some point, in order not to expand the vmdk unnecessarily. I carefully monitored guest used filesystem space and vmdk size, but surprise: at some point the zero-file got to 16GB; add the 4GB of ubuntu files and the vmdk should have been over 20GB, but it was only 15GB. It's as though the zeroes were nowhere written... judging also by the similarly-sized zipped vmdk.
I repeatedly tried the "compact" and "defragment" VM tools (in the host OS) but size didn't change. Then I found out about vmware-tools utility in the guest OS (ubuntu), but "shrink" function is not available since I use ext4. I don't understand the essences of "journaling file systems" but it seems that there exists this limitation.
The secure-delete documentation that I have read from various sources warns about this. Journaling filesystems, like ext3/ext4, and RAID systems are designed with journals and redundancy to reduce data loss. secure-delete offers no guarantee that all files will be 100% wiped on journaling filesystems or on RAID devices.
srm works and has become one of my Linux toolbox staples. It is free and easily available within the Linux world, so if you need a quick and easily-scriptable command that will wipe files and annihilate your top-secret cookie recipes, then srm from secure-delete is worth trying.
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