A severe vulnerability in the Linux and Unix networking stack has been identified in the last few days. The vulnerability described in CVE-2018–5390 (for Linux) and CVE-2018-6922 (for FreeBSD) allows a potential risk of relatively easy exploitable denial of service attack on an affected machine. The main source of the concern is the wide spread of this issue including plenty of Linux distributions, FreeBSD and some proprietary network equipment operating systems all running the affected Linux Kernels 4.9+ or having the networking code back ported.

The vulnerability is not a complex one. Introduced in Linux Kernel 4.9, it is related to the algorithm that processes the “out of order packages” in TCP connections. That algorithm is responsible to allow the receiving and rearrangement of TCP packets with non sequential numbers in the case of network issues. The problem with the algorithm which brings the potential vulnerability is that it is very resource expensive. According to the report and the calculations just a few thousand out of order packets even from the same source are enough to cause denial of service.

The good news is that some of the most widely spread server distros might not be affected and also the vulnerability still doesn’t have a proof-of-concept exploit So although it’s reported as a severe, this is still not a global issue and patches are already available.

The list of the affected, unaffected and patched distributions constantly updates:

Ubuntu 16.04 and older – Unaffected – Kernel 4.4 is before affected 4.9+

Ubuntu 18.04 – Affected – Patch available through APT

Fedora- Affected

FreeBSD – Affected

OpenSUSE – Unconfirmed

CentOS – Unconfirmed

Mikrotik released a new hotfix version of RouterOS related to the recent security vulnerabilities affecting Mikrotik based routers. Most of the security issues were related to Mikrotik proprietary management interface used by the Winbox tool ( port 8291 ) and led to the build up of a large botnet of infected, insecure routers.

The new version 6.42.6 is so far claimed to be free of the exploited vulnerabilities and provides some more cloud related improvements as well:

What’s new in 6.42.6 (2018-Jul-06 11:56):

• chr – added checksum offload support for Hyper-V installations;
• chr – added large send offload support for Hyper-V installations;
• chr – added multiqueue support on Xen installations;
• chr – added support for multiqueue feature on “virtio-net”;
• chr – added virtual Receive Side Scaling support for Hyper-V installations (might require more RAM assigned than in previous versions);
• chr – by default enable link state tracking for virtual drivers with “/interface ethernet disable-running-check=no”;
• chr – do not show IRQ entries from removed devices;
• chr – fixed interface name assign process when running CHR on Hyper-V;
• chr – fixed interface name order when “virtio-net is not being used on KVM installations;
• chr – fixed MTU changing process when running CHR on Hyper-V
• chr – fixed NIC hotplug for “virtio-net”;
• chr – improved balooning process;
• chr – improved boot time for Hyper-V installations;
• chr – provide part of network interface GUID at the beginning of “bindstr2” value when running CHR on Hyper-V;
• chr – reduced RAM memory required per interface;

Mikrotik RouterOS 6.42.6 is now available on CloudBalkan Cloud Routers

Mikrotik RouterOS has been a target for a decent amount of attack in last few months and this hasn’t stopped yet. Yesterday Mikrotik reported another security vulnerability resulting in remote access, infection and deploying a botnet code on infected devices. It is so far claimed to be a vulnerability in the Winbox (port 8291) interface although it is not confirmed that the issue limits only to this. Read More

June 19, 1993 is a date that mark one particularly important step in the open source world. On that date the name FreeBSD is officially agreed for what is today one of the most popular open source operating system. Read More

Fedora 28 Server image is now available for Cloud Servers.

The new version of Fedora arrived last week with a nice set of updates and new features. You can now try them on CloudBalkan.

On May, 1st the new version of Fedora was released. Fedora 28 comes right on time at the promised release date and delivers a plenty of new features and improvements. Read More

The Ubuntu Server 16.04 image on Cloud Servers has been just updated to deliver the latest upgrades included. As the image is one of the most popular choices for cloud servers we’ve refreshed it to Ubuntu 16.04.4 which is the latest version of the 16.04. Read More

With the recent launch of Ubuntu 18.04 on Friday, one more longly anticipated release came to world – LXD version 3.0.

Test version of LXD 3.0 were already around for a few months, promising a plenty of new features like better migration or clustering and more, but let’s see which of those made it to the final. Read More

New server operating system image is now available on Cloud Servers:

Ubuntu Server 18.04 LTS (Bionic Beaver)

Release date: April 27th 2018

Linux Kernel version: 4.15

Read the full article about the new release.

Bionic Beaver – the next long term release of the most popular Linux distribution has just been released. Read More