Tag: Security

Multiple vulnerabilities in FreeBSD NFS server code

last updated in Categories Security

FreeBSD is a free and open source operating system. The NFS (Network File System) is a server and client application that turn FreeBSD into a file sharing server. Users can upload or update files on a remote NFS server. NFS is standard on NAS (network attached storage) devices or sharing data for web servers. A new bug found in NFS server code which could allow a remote attacker to crash the NFS server, resulting in a denial of service (DoS) attack. Another possibility is to execute arbitrary code on the server.

400K+ Exim MTA affected by overflow vulnerability on Linux/Unix

last updated in Categories Linux News, Security

Exim is a free and open source message transfer agent (MTA) developed at the University of Cambridge. It is famous on Unix and Linux systems connected to the Internet. It is freely available under the terms of the GNU General Public Licence. There is a buffer overflow in base64d() of Exim MTA that allows an attacker to run code remotely. ALL versions of Exim MTA affected by overflow vulnerability i.e. CVE-2018-6789.
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Book Review: SSH Mastery – OpenSSH, PuTTY, Tunnels & Keys

last updated in Categories Open Source, Reviews, Security

Book Review: SSH Mastery
OpenSSH needs no introduction. OpenSSH is a free and open source suite of security-related software based on the SSH protocol. OpenSSH provides secure network communication and tunneling capabilities. OpenSSH gives peace of mind when communicating with Linux or Unix-like server over the Internet on the insecure network.

SSH is essential for both sysadmins and developers. The book “SSH Mastery” (2nd ed) talks about OpenSSH server, clients, encryption, public/private keys, VPNs and other security-related network-level utilities based on the Secure Shell SSH protocol.

OpenSSL drops TLS 1.0/1.1 support for Debian Unstable and what does it mean for Debian sid users?

last updated in Categories Debian Linux

From the announcement mailing list:

I’ve just uploaded a version of OpenSSL to unstable that disables the TLS 1.0 and 1.1 protocol. This currently leaves TLS 1.2 as the only supported SSL/TLS protocol version.

This will likely break certain things that for whatever reason still don’t support TLS 1.2. I strongly suggest that if it’s not supported that you add support for it, or get the other side to add support for it.

OpenSSL made a release 5 years ago that supported TLS 1.2. The current support of the server side seems to be around 90%. I hope that by the time Buster releases the support for TLS 1.2 will be high enough that I don’t need to enable them again.

Patch your FreeBSD server for openssh vulnerabilities [11/Jan/2017]

last updated in Categories Link

OpenSSH is critical for both sysadmin and programmers. It is an implementation of the SSH protocol suite, from OpenBSD project. It provides an encrypted session to your server.

OpenSSH multiple vulnerabilities

OpenSSH has multiple vulnerabilities as of 11th January 2017 running on FreeBSD operating system. From the advisory:

The ssh-agent(1) agent supports loading a PKCS#11 module from outside a trusted whitelist. An attacker can request loading of a PKCS#11 module across forwarded agent-socket. [CVE-2016-10009]

When privilege separation is disabled, forwarded Unix domain sockets would be created by sshd(8) with the privileges of ‘root’ instead of the authenticated user. [CVE-2016-10010]

Solution

I updated my vulnerable FreeBSD box via a binary patch:
# freebsd-update fetch
# freebsd-update install
# service sshd restart
# ps aux | grep -i ssh-agent
If found any ssh-agent process, kill all running ssh-agent:
# killall ssh-agent

Fig.01: Fixed FreeBSD-SA-17:01.openssh
Fig.01: Fixed FreeBSD-SA-17:01.openssh

For more info see FreeBSD security mailing list.

Why HTTPS for Everything?

last updated in Categories Link

HTTPS enables privacy and integrity by default. It is going to be next big thing. The internet’s standards bodies, web browsers, major tech companies, and the internet community of practice have all come to understand that HTTPS should be the baseline for all web traffic. Ultimately, the goal of the internet community is to establish encryption as the norm, and to phase out unencrypted connections. Investing in HTTPS makes it faster, cheaper, and easier for everyone.

Free SSL certificate for all

You can get your free ssl cert with Let’s Encrypt project. It is a certificate authority that launched on April 12, 2016 that provides free X.509 certificates for Transport Layer Security (TLS) encryption. See how to configure and use Let’s Encrypt TLS on a Ubuntu or Debian Linux:

In this tutorial, I will explain how to use Let’s Encrypt to install a free SSL certificate for Nginx web server along with how to properly deploy Diffie-Hellman on your nginx server to get SSL labs A+ score.

Touch ID Support for sudo in MacOS Terminal for MacBook Pro

last updated in Categories Link

Well, that was fast. Touch ID is a fingerprint recognition security feature, designed and released by Apple. It is currently available on the iPhone 5s/6/7 and Macbook pro-2016 editions. Many consider it as a huge security win for the MacBook Pro’s. This sounds amazing feature for command line users.

Say hello to sudo-touchid

sudo-touchid is a fork of sudo with Touch ID support on macOS (powered by the LocalAuthentication framework). Once compiled, it will allow you to authenticate sudo commands with Touch ID in the Terminal on supported Macs (such as the late 2016 MacBook Pros). Since Darwin sources for macOS 10.12 are not available yet, this project is based on sudo sources corresponding to OS X 10.11.6 and obtained from opensource.apple.com.

=> Download and usage information.