Recent content on PrivSec - A practical approach to Privacy and Security
IVPN is a fairly popular and generally trustworthy VPN provider. In this post, I will walk you through how to use the official IVPN client in a ProxyVM on Qubes OS. We will deviate from the official guide by using systemd path to handle DNAT. This will provide the same robustness as their approach to modify /opt/ivpn/etc/firewall.sh, while avoiding the risk that the modifications will be…
Premise ChromeOS encrypts user data on the disk by default. The implementation details are documented upstream but not relevant within the scope of this post. It is well-known that ChromeOS uses Google account passwords as the primary login credentials. This necessarily means that anyone with knowledge of the Google account password is able to unlock and therefore decrypt a ChromeOS user profile.…
To this date, Proton Mail doesn’t support MTA-STS for custom domains. While DANE for SMTP is a much better solution to the same problem, MTA-STS exists for a reason: many providers are slow at adopting DNSSEC. DNSSEC is essential to enabling standards such as DANE or SSHFP. Notably, Gmail still does not support DANE but has supported MTA-STS for years. Therefore, MTA-STS and DANE can…
macOS by default uses the unencrypted and unauthenticated Network Time Protocol (NTP) for time synchronization. A popular solution to mitigate this problem is to use ChronyControl to setup NTS. However, the application requires administrator privileges, which is less than ideal. In this post, I will go over how to leverage virtualization to setup a local Linux server, update its time using NTS,…
Currently, the Proxmox installer does not support setting up encryption with ZFS. Thus, we have to set it up manually. This post will go over how to use the native ZFS encryption with Proxmox. The post also assumes that the Proxmox installation is new and does not have any virtual machines or containers yet. Encrypting the rpool/ROOT dataset Proxmox installs its system inside the rpool/ROOT…
Update: DivestOS has been discontinued and downloads are no longer available. This will turn your device into a purely penetration testing device, and it will be very insecure for any other purpose. Please do not do this on your daily driver. This procedure should work without modification on many devices using the standard Android bootloader (not Samsung). However, every device has unique quirks…
These websites contain a significant amount of factual technical information and are generally good resources to follow. NAME NOTES GrapheneOS FAQ Information on GrapheneOS and general Android security. Madaidan’s Insecurities Highlighting security issues within popular technologies, debunking misinformation, and providing free security guidance for everyone. Wonderfall’s Lab Thoughts…
Given the current censorship situation in Iran, I decided to have a look at the Signal TLS Proxy. One thing immediately jumped out - the NGINX image has not been updated for years. In fact, NGINX 1.18 is so old that it has gone end of life for a year and a half as of this writing. If you are deploying or maintaining a Signal TLS Proxy, I highly recommend that you use the upstream nginx:alpine…
Update: This is no longer reproducible on Android 13 QPR1 and Android 14 Developer Preview 1. Before We Start… I have been aware of this issue for awhile now (since at least Android 11), though I have not done enough testing to see what actually causes the leak nor do I have any workaround at the moment. My guess is that applications which launch early when you log into a secondary profile…
Before We Start… I sent Proton an email regarding this issue in late August 2022 and was told they are working on fixing it, though it will take some time as it requires some architectural changes in how the killswitch works. The Leak Ideally, when implementing a killswitch, a VPN client should drop all connections on non-VPN interfaces except when the connection is to the VPN…
MAC address randomization Note that Ethernet connections can still be tracked via switch ports, and WiFi connections can be broadly localized by access point. Furthermore, MAC address spoofing and randomization depends on firmware support from the interface. Most modern network interface cards support the feature. There are three different aspects of MAC address randomization in NetworkManager,…
Mullvad is a fairly popular and generally trustworthy VPN provider. In this post, I will walk you through how to use the official Mullvad client in a ProxyVM on Qubes OS. This method is a lot more convenient than the official guide from Mullvad (which recommends that you manually load in OpenVPN or Wireguard profiles) and will let you seamlessly switch between different location and network setups…
MirageOS is a library operating system with which you can create a unikernel for the sole purpose of acting as Qubes OS’s firewall. In this post, I will walk you through how to set this up. Advantages Small attack surface. The unikernel only contains a minimal set of libraries to function, so it has a much smaller attack surface than a general purpose operating system like a Linux…
Linux is not a secure desktop operating system. However, there are steps you can take to harden it, reduce its attack surface, and improve its privacy. Before we start… Some of the sections will include mentions of unofficial builds of packages like linux‑hardened, akmod, hardened_malloc, and so on. These are not endorsements — they are merely to show that you have options to easily…
This post will go over setting up Split GPG, then setting up Split SSH with the same PGP keys. Effectively, we are emulating what you can do with a PGP smartcard on Qubes OS. Split GPG Follow the official Qubes OS documentation to set this up. Note that if you already have a PGP key with a passphrase, you can remove it by installing pinentry-gtk to vault’s TemplateVM, then run gpg2…
Badness enumeration is the concept of making a list of known bad actors and attempting to block them. While it seems intuitive at first glance, badness enumeration should not be relied on for privacy or security. In many cases, it actually does the exact opposite and directly harms the user. This post will attempt to explain why badness enumeration as a concept is flawed and give some examples of…
Lokinet is an Internet overlay network utilizing onion routing to provide anonymity for its users, similar to Tor network. This post will go over how to set it up on Qubes OS. Before we start… This post should not be considered an endorsement of Lokinet in any shape or form. Lokinet is currently not in a good state — it has not had a public release since 2022, and most free public…
Android is a very secure and robust operating system out of the box. This post will be less of a “hardening guide”, but more of a non-exhaustive list of tips when it comes to buying and using Android phones. Android Devices Recommended Phones Google Pixel phones are the only devices I would recommend for purchase. Pixel phones have stronger hardware security than any other Android…
Virtual Private Networks are a way of creating a protected and private network over the open Internet. It was originally designed to provide remote access to an internal corporate network. However, in recent years, it has also been used by commercial VPN companies to hide their clients’ real IP address from third-party websites and services. Should I use a VPN? Yes, unless you are already…
Android is a secure operating system that has strong app sandboxing, Verified Boot (AVB), and a robust permission control system. When you buy an Android phone, the device’s default operating system often comes with invasive integration with apps and services that are not part of the Android Open-Source Project. An example of such is Google Play Services, which has irrevocable privileges to…
The development effort of PrivSec.dev is a very personal process compared to “traditional” ways of developing a community website. Your recommendations and ideas behind it will be carefully reviewed, often resulting in critique and criticism. Know that this happens because everyone involved wants to see the best possible solution for the overall success of PrivSec.dev. If however,…
There is a common misconception among privacy communities that Linux is one of the more secure operating systems, either because it is open-source or because it is widely used in the cloud. However, this is a far cry from reality. There is already a very in-depth technical blog explaining the various security weaknesses of Linux by Madaidan, Whonix’s Security Researcher. This page will…
PrivSec.dev as a project does not collect any personal information. We do not track you using cookies, collect your fingerprints, or use any tracking scripts. Hosting Provider We use Cloudflare for domain registration, DNS, and web hosting. We use Netlify for website previews. We do not use Netlify assets optimization, so nothing is hosted on CloudFront. We do not have access to your IP addresses…
Mailcow is a fairly popular self-hosted mail server. If you use it, there are a few ways you can improve its security by following these steps. Postfix Configuration Consider disabling weak ciphers and TLS versions below 1.2 in data/conf/postfix/extra.cf: tls_high_cipherlist =…
The first task a person should do when taking steps to protect their privacy and security is to make a threat model. Defining a threat To make a threat model, we must first define a threat. A common mistake made by people who are just getting into the privacy space is to define the threat as “big-tech companies.” There is a fundamental problem with this definition: Why are we not…
Not all Linux distributions are created equal. When choosing a Linux distribution, there are several things you need to keep in mind. Release Cycle You should choose a distribution which stays close to the stable upstream software releases, typically rolling release distributions. This is because frozen release cycle distributions often don’t update package versions and fall behind on security…
PrivSec.dev is made by a group of enthusiastic individuals looking to provide practical privacy and security advice for the end user. We are security researchers, developers, system administrators… generally people with technical knowledge and work in the field. We focus on in-depth system configuration, security analysis, and software/hardware recommendations. Our site is based on…
The domain costs us $12/year to renew from Google. We got our repository hosted for free on GitHub. We got our site hosted $10/month with Netlify. It costs Tommy ~$20/month to run the mail server, but that server is used for a bunch of his projects, not just PrivSec, and we doubt it will be used that much anyways. The point is, this website does not cost much to run, and as such we will not be…
Multi-factor authentication is a security mechanism that requires additional verification beyond your username (or email) and password. This usually comes in the form of a one-time passcode, a push notification, or plugging in and tapping a hardware security key. Common protocols Email and SMS MFA Email and SMS MFA are examples of the weaker MFA protocols. Email MFA is not great as whoever…
Passwordless authentication with OpenSSH keys has been the de facto security standard for years. SSH keys are more robust since they’re cryptographically sane by default, and are therefore resilient to most bruteforce atacks. They’re also easier to manage while enabling a form of decentralized authentication (it’s easy and painless to revoke them). So, what’s the next step?…
Containers aren’t that new fancy thing anymore, but they were a big deal. And they still are. They are a concrete solution to the following problem: - Hey, your software doesn’t work… - Sorry, it works on my computer! Can’t help you. Whether we like them or not, containers are here to stay. Their expressiveness and semantics allow for an abstraction of the OS dependencies…
While source code is critical for user autonomy, it isn’t required to evaluate software security or understand run-time behavior. One of the biggest parts of the Free and Open Source Software definitions is the freedom to study a program and modify it; in other words, access to editable source code. I agree that such access is essential; however, far too many people support source…
Maintained Compatibility List for International Banking Apps This list includes banking apps that have been tested, submitted, reviewed, and verified as compatible. LIST | SUBMIT | UPDATE | POSSIBLE WORKAROUND SOLUTIONS Introduction Welcome to the crowd-sourced dataset for GrapheneOS users on currently supported devices. New visitors are encouraged to read the official usage guide on banking apps…
F-Droid is a popular alternative app repository for Android, especially known for its main repository dedicated to free and open-source software. F-Droid is often recommended among security and privacy enthusiasts, but how does it stack up against Play Store in practice? This write-up will attempt to emphasize major security issues with F-Droid that you should consider. Before we start, a few…