Category Archives: Security

Windows : How to open a port on firewall from command line (CLI)

Windows Firewall can be configured from the GUI (by using firewall.cpl UI console) and also using the command line. This quick tutorial will cover how to manipulate the rules from CLI to open, block a port and delete a rule. In  a nutshell, here is the command sample:

The rest of this article will… Read More »

Linux : OSSEC WebUI not showing information after PHP upgrade

You may have noticed that the OSSEC Web Interface stopped working (as of today on a new installation) or after updating PHP on your server. Looking at the logs, you most likely found a similar entry: PHP Fatal error: Uncaught Error: Call to undefined function split() in /var/www/html/ossec/lib/os_lib_agent.php:111\nStack trace:\n#0 /var/www/html/ossec/site/main.php(33): os_getagents(Array)\n#1 /var/www/html/ossec/index.php(126): include(‘/var/www/html/o…’)\n#2 {main}\n thrown… Read More »

PanOS : Failed to load into software manager

The following error message may happen from time to time when attempting to load new software version in Palo Alto Firewall or Panorama : Successfully downloaded Preloading into software manager Error: Image File Authentication Error Failed to load into software manager. Please retry. Post processing failed. Please retry PanOS always do software image integrity check… Read More »

Linux : How to change the OpenVPN lockout time policy

By default, OpenVPN has 15 minutes timeout lockout policy for consecutive unsuccessful authentication attempt (whatever you are using Local, PAM or LDAP authentication). If you want to change it to shorter or longer time period, follow these easy steps below : 1. Push the new timeout value to the configuration using this command (this example… Read More »

JunOS : Port forwarding on Juniper SRX

A friend of mine who was used to the legacy and EOL SSG/ScreenOS platform and he just jumped into the new world of SRX/JunOS gave me the motivation to write this article. As the syntax is quite different between the two platform, it may be harder to get at first and the following example should… Read More »

Windows : Nmap error dnet: Failed to open device eth0

Experiencing the following issue with Nmap on Windows? $ nmap -P0 -sS -T5 0.0.0.0 Starting Nmap 7.70 ( https://nmap.org ) at 2019-06-04 03:14 ric dnet: Failed to open device eth0 QUITTING! It appears that some version of Npcap (or WinPcap) is causing issues. Updating Npcap to version 0.995 solve this issue. If you are running… Read More »

Web : SSL error NET::ERR_CERT_SYMANTEC_LEGACY

Since April 2018, I have noticed the following SSL error with Google Chrome and Safari’s latest versions : NET::ERR_CERT_SYMANTEC_LEGACY All Symantec SSL/TLS certificates issued prior June 1st 2016 will output this warning from now on since the latest updates. Web user, nothing is wrong on your side, the site owner must re-issue his certificate, even… Read More »