Kernel rootkits and countermeasures
The Spy Within
© © Igor Korionov, 123rf. .com
Rootkits allow attackers to take complete control of a computer. We describe the tricks intruders use to gain access to the Linux kernel and provide guidelines on hardening the kernel against such attacks.
In response to a question asked in parliament, the German Federal Government responded in May 2012 that it was able to decrypt PGP messages or SSH connections, at least partially [1]. Experts were exasperated when they heard this. No one seriously believed that PGP encryption had been cracked. More likely, data is sniffed before encryption or after decryption, or the secret service possesses the private key and, possibly, the associated password. Germany's "Federal Trojan" [2] can infiltrate the kernel as a rootkit for this purpose.
Classically, the term "rootkit" refers to a piece of software that gives an attacker camouflaged access to, and thus control over, a machine. Userland rootkits tend to modify applications to do this. In comparison, the much more powerful kernel rootkits change kernel data structures and code – for example, through system call hijacking.
Hijacked
Hijacking a system call is simple in theory. A system call, which is a job for the operating system kernel, is identified by a number that is used as an index in a table with function addresses. These addresses point to functions that implement the respective system calls. In the Linux kernel, this table is sys_call_table.
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
US / Canada
UK / Australia
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Linux Mint 22.3 Now Available with New Tools
Linux Mint 22.3 has been released with a pair of new tools for system admins and some pretty cool new features.
-
New Linux Malware Targets Cloud-Based Linux Installations
VoidLink, a new Linux malware, should be of real concern because of its stealth and customization.
-
Say Goodbye to Middle-Mouse Paste
Both Gnome and Firefox have proposed getting rid of a long-time favorite Linux feature.
-
Manjaro 26.0 Primary Desktop Environments Default to Wayland
If you want to stick with X.Org, you'll be limited to the desktop environments you can choose.
-
Mozilla Plans to AI-ify Firefox
With a new CEO in control, Mozilla is doubling down on a strategy of trust, all the while leaning into AI.
-
Gnome Says No to AI-Generated Extensions
If you're a developer wanting to create a new Gnome extension, you'd best set aside that AI code generator, because the extension team will have none of that.
-
Parrot OS Switches to KDE Plasma Desktop
Yet another distro is making the move to the KDE Plasma desktop.
-
TUXEDO Announces Gemini 17
TUXEDO Computers has released the fourth generation of its Gemini laptop with plenty of updates.
-
Two New Distros Adopt Enlightenment
MX Moksha and AV Linux 25 join ranks with Bodhi Linux and embrace the Enlightenment desktop.
-
Solus Linux 4.8 Removes Python 2
Solus Linux 4.8 has been released with the latest Linux kernel, updated desktops, and a key removal.