A Facebook user asked how to forbid write access to an external USB drive, allowing only for read-only access. This article explains how to do that with the help of udev.
How to Make System Logs Append-Only
During an intrusion, an intruder leaves signs of his actions in various system logs. Without reliable logs, it could be very difficult to figure out how the attacker got in, or where the attack came from. This information is crucial in analyzing the incident. It is evident that the logs are a valuable audit trail that should be well protected.
Of course, when an intruder gets in to the system, they will try to remove all traces. So, how can we stop an intruder from removing evidence?
Yoast SEO: How to Use a Custom Stylesheet for Sitemaps
The article describes a way to use custom XML stylesheets for sitemaps generated by Yoast SEO plugin. Custom stylesheets can be good if you want to get rid of spammy links back to Yoast website in every generated sitemap file.
Newer Is Not Necessarily Better: Updated Yoast SEO to 8.3
Yesterday I made a terrible mistake by updating Yoast SEO plugin to its latest version (8.3) without prior testing. This resulted in significant server load. Luckily, the fix was easy.
nginx: Mitigating the BREACH Vulnerability with Perl and SSI or Addition or Substitution Modules
BREACH (Browser Reconnaissance and Exfiltration via Adaptive Compression of Hypertext) is a security exploit against HTTPS when using HTTP compression. This article shows several ways to deal with BREACH using Length Hiding technique with nginx’s builtin modules.
How to Import Cloudflare IP List into nginx ACL Automatically
When using Cloudflare to hide IP address of the origin server (for example, to protect against DoS attacks), it is important to configure ACLs to allow connections to the origin server only from Cloudflare IPs. However, the list of Cloudflare IP ranges is not static, it changes over time. This post describes how to import this list into nginx automatically.
How to Get Maximum Score in SSL Labs Test (nginx)
This article provides a configuration for nginx that successfully passes SSL Labs tests with A or A+ mark, and 100% score for all metrics (certificate, protocol support, key exchange, cipher strength).
Mapping OpenSSL Cipher Suite Names to RFC Names
Correspondence between OpenSSL cipher suite names and RFC names taken from http://testssl.sh/openssl-rfc.mapping.html.
TLS Configuration for nginx to Get A+ in HTBridge and SSL Labs Tests
This post presents a TLS configuration for nginx to get A+ score in HTBridge and SSL Labs tests. According to HTBridge, this configuration is compliant with PCI DSS, NIST, and HIPAA guidelines.
Signal Desktop and Failed to Map Segment from Shared Object Error
Signal is a great encrypted communications application built upon Electron framework. Couple of months ago I faced the issue that Signal had failed to start showing a message like this: “Uncaught Exception: Error: /tmp/.org.chromium.Chromium.j4ITUv: failed to map segment from shared object”.
Here is the solution.