An insidious spam botnet attacks Charly
BOT POSSE
While going about his normal duties, Linux Magazine author Charly Kühnast was hit with a mean attack. Charly’s separate anti-spam server, which sits in front of his mail server, saved him from the mail storm.
A sunny Tuesday in July. I’m just typing my Sysadmin column for Linux Magazine. It’s 2.00 pm by the time I take a glance at the monitor that gives me the latest load and traffic data for the critical servers I manage. Lo and behold, the reject line in the spam filter graph has just skyrocketed (See Figure 1). The article will have to wait. The server is rejecting large quantities of mail at an early stage of the SMTP dialog. I suspect a wave of spam with clumsily spoofed envelopes. That’s nothing new: for each legitimate email I receive, I get at least two spam mails. But I still decide to open an SSH connection to the spam filter, which is running on a separate machine, and I can’t believe my eyes when I discover 140 parallel SMTP connections. That’s ten times the normal level. And it’s unusual for the server just to drop the connections like that.
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
-
Fedora Asahi Remix 41 Available for Apple Silicon
If you have an Apple Silicon Mac and you're hoping to install Fedora, you're in luck because the latest release supports the M1 and M2 chips.
-
Systemd Fixes Bug While Facing New Challenger in GNU Shepherd
The systemd developers have fixed a really nasty bug amid the release of the new GNU Shepherd init system.
-
AlmaLinux 10.0 Beta Released
The AlmaLinux OS Foundation has announced the availability of AlmaLinux 10.0 Beta ("Purple Lion") for all supported devices with significant changes.
-
Gnome 47.2 Now Available
Gnome 47.2 is now available for general use but don't expect much in the way of newness, as this is all about improvements and bug fixes.
-
Latest Cinnamon Desktop Releases with a Bold New Look
Just in time for the holidays, the developer of the Cinnamon desktop has shipped a new release to help spice up your eggnog with new features and a new look.
-
Armbian 24.11 Released with Expanded Hardware Support
If you've been waiting for Armbian to support OrangePi 5 Max and Radxa ROCK 5B+, the wait is over.
-
SUSE Renames Several Products for Better Name Recognition
SUSE has been a very powerful player in the European market, but it knows it must branch out to gain serious traction. Will a name change do the trick?
-
ESET Discovers New Linux Malware
WolfsBane is an all-in-one malware that has hit the Linux operating system and includes a dropper, a launcher, and a backdoor.
-
New Linux Kernel Patch Allows Forcing a CPU Mitigation
Even when CPU mitigations can consume precious CPU cycles, it might not be a bad idea to allow users to enable them, even if your machine isn't vulnerable.
-
Red Hat Enterprise Linux 9.5 Released
Notify your friends, loved ones, and colleagues that the latest version of RHEL is available with plenty of enhancements.