Linux – Insinuator.net

July 3, 2025 by Alexander Moch

Insecure Boot: Injecting initramfs from a debug shell

Many Linux hardening guides focus on well-known protections: full-disk encryption, Secure Boot, and password-protected bootloaders. While these measures are critical, they often overlook a subtle but serious attack vector: the ability to drop into a debug shell via the Initial RAM Filesystem (initramfs). This oversight can enable an attacker with brief physical access to bypass conventional boot protections and inject persistent malware into the system.

In this post, it is demonstrated how this attack works on modern Linux distributions, such as Ubuntu and Fedora, and explained why existing guidance often fails to mention it.

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Breaking

June 17, 2025 by Nils Emmerich

Disclosure: Multiple Vulnerabilities in X.Org X server prior to 21.1.17 and Xwayland prior to 24.1.7

The X11 Window System has been used since September 1987 for Unix desktop systems, allowing applications to display their windows. Today, one of the server implementations of the protocol is the X.Org X server and XWayland, which both use the same codebase. While reviewing the X server, several legacy security issues were identified. These appear to originate from earlier design stages when security considerations were less prominent. Despite the project’s maturity and widespread use, some of these issues have persisted.

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Misc

May 14, 2024 by Tillmann Oßwald

Linux Character Devices: Exploring systemd-run and pkexec

In this blog post, we quickly look into issues involving character devices. As is typical for Linux, everything is a file, so character devices are referenced as files, such as pseudo terminals (pts) under /dev/pts/. man pty briefly introduces the topic. Essentially, it is used to connect a program, such as a terminal emulator, to a shell. In the end, a pty can read and write like a regular file. A colleague already brought up the topic of ptys and character devices. But more recently a Twitter post and the accompanying advisory piqued my interest.

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Building

June 6, 2018 by Frank Block

New Release of Glibc Heap Analysis Plugins

After quite some time and work, I’m happy to announce the new release of the Linux Heap Analysis Plugins, which are now part of the Rekall project, but not yet part of an official Rekall release, so you have to grab them manually.
This release fixes several bugs and adds the following features:
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Misc

February 23, 2018 by Niklaus Schiess

Creating Static Binaries for Nmap, Socat and other Tools

In various scenarios it might be helpful or even required to have a statically compiled version of Nmap available. This applies to e.g. scenarios where only limited user privileges are available and installing anything to the system might not be desirable.

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Events

December 1, 2017 by Jacky Hammer

Let’s talk about RFC 6980

Following my work with the FreeBSD implementation of RFC 6980 I was happy to present my work at last week’s DENOG 9 meeting.
To make it available to anyone who did not meet me there and go into some more detail that would have exceeded the boundaries of the talk, I will cover the topic here.

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Events

September 6, 2017 by Frank Block

DFRWS USA 2017

As mentioned in my last blogpost, I had the pleasure to participate in this years DFRWS USA and present our paper. The paper and presentation can be freely viewed and downloaded here or here. Note that there is also an extended version of the paper, which can be downloaded here.

The keepassx, zsh and heap analysis plugins are now also part of the Rekall release candidate 1.7.0RC1, so it’s easier to get started.

The conference had some great talks and workshops, which I’m going to briefly sum up.
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Building

July 13, 2017 by Frank Block

Release of Glibc Heap Analysis Plugins for Rekall

I’m happy to announce the release of several Glibc heap analysis plugins (for Linux), resp. plugins to gather information from keepassx and zsh, which are now included in the Rekall Memory Forensic Framework. This blogpost will demonstrate these plugins and explain how they can be used. More detailed information, including real world scenarios, will be released after the talk at this years DFRWS USA.

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Misc

July 15, 2015 by Benjamin Schwendemann

Solving sound issues when using WebEx with Linux and Firefox

Hello everybody,

Some of you might use WebEx in their daily life. And some of you might use Linux (as I and many of us do). However, this combination often results in issues with your PC’s sound or microphone use in a WebEx session.

The problem here is that WebEx won’t run as intended with Firefox and JRE x64. But the solution is quite easy! Use the x86-versions of each.

Probably you don’t want to replace your x64 versions of either of them — and neither do I. So I wrote a little script which helps you to quickly switch to the x86 versions, while you still have the x64 versions installed. And here is how to do it:

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Building

December 30, 2014 by Matthias Luft

Hardening Against Local PrivEsc: Protecting Your Links

Following up on this post, we want to provide some details on two rather new (well, compared to its lifespan) Linux kernel parameters — and emphasize the need to enable those:

fs.protected_hardlinks
fs.protected_symlinks

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