How the L1 Terminal Fault vulnerability affects Linux systems

Announced just yesterday in security advisories from Intel, Microsoft and Red Hat, a newly discovered vulnerability affecting Intel processors (and, thus, Linux) called L1TF or “L1 Terminal Fault” is grabbing the attention of Linux users and admins. Exactly what is this vulnerability and who should be worrying about it?L1TF, L1 Terminal Fault, and Foreshadow
The processor vulnerability goes by L1TF, L1 Terminal Fault, and Foreshadow. Researchers who discovered the problem back in January and reported it to Intel called it “Foreshadow”. It is similar to vulnerabilities discovered in the past (such as Spectre).This vulnerability is Intel-specific. Other processors are not affected. And like some other vulnerabilities, it exists because of design choices that were implemented to optimize kernel processing speed but exposed data in ways that allowed access by other processes.To read this article in full, please click here READ MORE HERE…

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The aftermath of the Gentoo GitHub hack

Gentoo GitHub hack: What happened?
Late last month (June 28), the Gentoo GitHub repository was attacked after someone gained control of an admin account. All access to the repositories was soon removed from Gentoo developers. Repository and page content were altered. But within 10 minutes of the attacker gaining access, someone noticed something was going on, 7 minutes later a report was sent, and within 70 minutes the attack was over. Legitimate Gentoo developers were shut out for 5 days while the dust settled and repairs and analysis were completed.The attackers also attempted to add “rm -rf” commands to some repositories to cause user data to be recursively removed. As it turns out, this code was unlikely to be run because of technical precautions that were in place, but this wouldn’t have been obvious to the attacker.To read this article in full, please click here READ MORE HERE…

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22 essential security commands for Linux

There are many aspects to security on Linux systems – from setting up accounts to ensuring that legitimate users have no more privilege than they need to do their jobs. This is look at some of the most essential security commands for day-to-day work on Linux systems.sudo
Running privileged commands with sudo  – instead of switching user to root  – is one essential good practice as it helps to ensure that you only use root privilege when needed and limits the impact of mistakes. Your access to the sudo command depends on settings in the /etc/sudoers and /etc/group files. [ Two-Minute Linux Tips: Learn how to master a host of Linux commands in these 2-minute video tutorials ]
$ sudo adduser shark
Adding user `shark’ …
Adding new group `shark’ (1007) …
Adding new user `shark’ (1007) with group `shark’ …
Creating home directory `/home/shark’ …
Copying files from `/etc/skel’ …
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
Changing the user information for shark
Enter the new value, or press ENTER for the default Full Name []: shark Room Number []: Work Phone []: Home Phone []: Other []:
Is the information correct? [Y/n] Y

If you run sudo and ask who you are, for example, you’ll get confirmation that you’re running the command as root.To read this article in full, please click here(Insider Story) READ MORE HERE…

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22 essential Linux security commands

There are many aspects to security on Linux systems – from setting up accounts to ensuring that legitimate users have no more privilege than they need to do their jobs. This is look at some of the most essential security commands for day-to-day work on Linux systems.sudo
Running privileged commands with sudo  – instead of switching user to root  – is one essential good practice as it helps to ensure that you only use root privilege when needed and limits the impact of mistakes. Your access to the sudo command depends on settings in the /etc/sudoers and /etc/group files. [ Two-Minute Linux Tips: Learn how to master a host of Linux commands in these 2-minute video tutorials ]
$ sudo adduser shark
Adding user `shark’ …
Adding new group `shark’ (1007) …
Adding new user `shark’ (1007) with group `shark’ …
Creating home directory `/home/shark’ …
Copying files from `/etc/skel’ …
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
Changing the user information for shark
Enter the new value, or press ENTER for the default Full Name []: shark Room Number []: Work Phone []: Home Phone []: Other []:
Is the information correct? [Y/n] Y

If you run sudo and ask who you are, for example, you’ll get confirmation that you’re running the command as root.To read this article in full, please click here(Insider Story) READ MORE HERE…

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Unix: How random is random?

On Unix systems, random numbers are generated in a number of ways and random data can serve many purposes. From simple commands to fairly complex processes, the question “How random is random?” is worth asking.EZ random numbers
If all you need is a casual list of random numbers, the RANDOM variable is an easy choice. Type “echo $RANDOM” and you’ll get a number between 0 and 32,767 (the largest number that two bytes can hold).$ echo $RANDOM
29366

Of course, this process is actually providing a “pseudo-random” number. As anyone who thinks about random numbers very often might tell you, numbers generated by a program have a limitation. Programs follow carefully crafted steps, and those steps aren’t even close to being truly random. You can increase the randomness of RANDOM’s value by seeding it (i.e., setting the variable to some initial value). Some just use the current process ID (via $$) for that. Note that for any particular starting point, the subsequent values that $RANDOM provides are quite predictable.To read this article in full, please click here READ MORE HERE…

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The complexity of password complexity

Deploying password quality checking on your Debian-base Linux servers can help to ensure that your users assign reasonable passwords on their accounts, but the settings themselves can be a bit misleading. For example, setting a minimum password length of 12 characters does not mean that your users’ passwords will all have twelve or more characters. Let’s stroll down Complexity Boulevard and see how the settings work and examine some settings worth considering.First, if you haven’t done this already, install the password quality checking library with this command:apt-get -y install libpam-pwquality

The files that contain most of the settings we’re going to look at will be:To read this article in full, please click here READ MORE HERE…

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Book Review: Practical Packet Analysis: Using Wireshark to Solve Real-World Network Problems

The overall equation is pretty simple: If you want to understand network traffic, you really should install Wireshark. And, if you really want to use Wireshark effectively, you should consider this book. Already in its third edition, Practical Packet Analysis both explains how Wireshark works and provides expert guidance on how you can use the tool to solve real-world network problems.Yes, there are other packet analyzers, but Wireshark is one of the best, works on Windows, Mac, and Linux, and is free and open source. And, yes, there are other books, but this one focuses both on understanding the tool and using it to address the kind of problems that you’re likely to encounter.To read this article in full, please click here READ MORE HERE…

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