Posts filed under Tips'n Tricks

Cisco ISE v2.6 and Google ChromeOS

While playing around with the new Cisco Identity Service Engine (ISE) v2.6 (patch2) I stumbled upon a security feature while testing Wireless 802.1x access with an Acer Chromebook (ChromeOS v75.0.3770.144). When connecting to the 802.1x enabled SSID the connection failed, while other devices (Windows 10, Apple iOS and MacOS) connected just fine.

The problem is the client EAP handshake and usually this relates to untrusted server certificates. This happens to me a lot since I use different RADIUS services for my testing SSID’s.
So after clearing the SSID settings (forget) on the Chromebook it should work, but it didn’t.

The logging showed that the EAP handshake failed because the client didn’t offer a suitable cipher to the ISE server.

Turns out that Cisco ISE v2.6 has SHA1 disabled by default, and you need to enable it in:

Administration -> System -> Settings -> Security Settings

With the setting ‘Allow SHA1 Ciphers’, and ‘Allow only TLS_RSA_WITH_AES_128_CBC_SHA’ the Chromebook was able to connect to the 802.1x enabled SSID using old/depricated ciphers.

Now I wonder why the Chromebook still uses SHA1 based ciphers for secure communications, since Google Chrome started to abandon SHA1 as one of the first browsers….

Even installing the ‘Powerwash for added security’ feature in ChromeOS didn’t enable or add stronger ciphers on the Chromebook.

Posted on July 31, 2019 and filed under Tips'n Tricks, Security.

Install Cisco Identity Services Engine v2.4 From USB

The Cisco Identity Service Engine (ISE) is a NAC solution used for accessing the network. The version (while writing this post) is v2.4.

For a new implementation of Cisco ISE I had to re-image 2 SNS-3595 appliances with the latest software. This can be done in various ways;

  1. Write the ISE iso to USB and boot / install from the USB flash-drive

  2. Use the JAVA/HTML5 KVM option through the CICM interface

  3. Hookup a USB DVD player with a dual-layer DVD containing the appropriate ISO file

The preferred option is the USB flash-drive, since it’s the fastest, but only if you are able to boot from USB….. After trying several USB flash drives with the tool recommended in the Cisco manual I gave up. No way that the Boot menu saw the USB flash drive. So after wasting several hours doing that I opted for the KVM install method.

Juniper SRX, Virtual Routers, and SNMPv3

In this continuing story about Junos and virtual routers an episode about SNMPv3.

A simple SNMPv3 config for Junos would be the following:

set snmp v3 usm local-engine user authpriv authentication-md5 authentication-password My_Password_01
set snmp v3 usm local-engine user authpriv privacy-aes128 privacy-password My_Password_02
set snmp v3 vacm security-to-group security-model usm security-name v3test group v3test
set snmp v3 vacm security-to-group security-model usm security-name authpriv group v3test
set snmp v3 vacm access group v3test default-context-prefix security-model any security-level authentication read-view v3testview
set snmp v3 vacm access group v3test default-context-prefix security-model any security-level authentication write-view v3testview
set snmp v3 vacm access group v3test default-context-prefix security-model any security-level authentication notify-view v3testview
set snmp v3 vacm access group v3test default-context-prefix security-model any security-level privacy read-view v3testview
set snmp v3 vacm access group v3test default-context-prefix security-model any security-level privacy write-view v3testview
set snmp v3 vacm access group v3test default-context-prefix security-model any security-level privacy notify-view v3testview
set snmp v3 snmp-community v3test security-name v3test
set snmp view v3testview oid system include
set snmp view v3testview oid .1 include

Authenticating with the correct credentials (U: authpriv, P: My_Password_01) will give results in a single (default) virtual router.

Using this config in a multiple VR environment will result in Authentication and/or authorization errors. Reason being the not using the root/single VR configuration.

Adding some details to the config, AND altering the actual SNMPv3 query will solve that.

set snmp v3 usm local-engine user authpriv authentication-md5 authentication-password My_Password_01
set snmp v3 usm local-engine user authpriv privacy-aes128 privacy-password My_Password_02
set snmp v3 vacm security-to-group security-model usm security-name authpriv group v3test
set snmp v3 vacm access group v3test context-prefix DEFAULT security-model any security-level authentication read-view v3testview
set snmp v3 vacm access group v3test context-prefix DEFAULT security-model any security-level authentication write-view v3testview
set snmp v3 vacm access group v3test context-prefix DEFAULT security-model any security-level authentication notify-view v3testview
set snmp v3 vacm access group v3test context-prefix DEFAULT security-model any security-level privacy read-view v3testview
set snmp v3 vacm access group v3test context-prefix DEFAULT security-model any security-level privacy write-view v3testview
set snmp v3 vacm access group v3test context-prefix DEFAULT security-model any security-level privacy notify-view v3testview
set snmp v3 snmp-community v3test security-name v3test
set snmp view v3testview oid system include
set snmp view v3testview oid .1 include
set snmp routing-instance-access access-list DEFAULT

The main differences are:

  • context-prefix <VR-NAME>
  • snmp routing-instant-access access-list <VR-NAME>

Having done that, AND adding a context parameter to the actual query will give the correct results.

Posted on June 27, 2018 and filed under Junos, Security, Tips'n Tricks.

Juniper SRX, Routing Instances, and Syslog Challenges

In the previous post I described the issue I had with routing instances and DHCP-relay, and how I fixed it. It turns out that DHCP-relay wasn't my only problem. Turns out that syslog also stopped at the time I implemented the routing instances.

Syslog-gap

To solve this I needed to inject the route to my syslog server (Splunk) in the global routing instance by using policy options.

set policy-options policy-statement syslog-policy term 10 from instance DEFAULT
set policy-options policy-statement syslog-policy term 10 from route-filter 192.168.20.0/24 exact
set policy-options policy-statement syslog-policy term 10 then accept
set policy-options policy-statement syslog-policy then reject

set routing-options instance-import syslog-policy
Posted on June 25, 2018 and filed under Annoying, Security, Tips'n Tricks.

Juniper vSRX Firewall and VMWare Workstation 14

For a work related project, I wanted to run the Juniper vSRX firewall (v15.1X49-D110) on my work laptop by using VMWare Workstation Pro 14. Unfortunately, the installation (importing the Juniper vSRX OVA file resulted in a VMWare Workstation crash.

Enhancing Sonoff TH16 Functionality and Domoticz Integration

In my previous blogpost, the Sonoff worked, but was lacking a manual override. The switch could only be triggered by Domoticz. Since it also has a physical push button (connected to GPIO0 (D3)), it can be switched by hand. All that needs to be done is:

  1. Create a new switch device in the Sonoff
  2. Enable 'Rules' in the Tools / advanced settings
  3. Create a rule
  4. Change the On/Off commands in the switch parameters in Domoticz
Posted on January 1, 2018 and filed under Hardware, Programming, Raspberry Pi, Tips'n Tricks, Domotica.

Flashing the Sonoff TH16 Wireless Switch

The Sonoff TH16 is an inexpensive piece of hardware that can be controlled over WiFi. Apart from the switch (that's capable of handling electrical currents up to 16A) there's an interface for temperature and humidity. The actual temp/humid sensor is sold separately (in most cases).

Posted on December 31, 2017 and filed under Gadgets, Hardware, Programming, Raspberry Pi, Tips'n Tricks, Domotica.

Add Routes To Ubuntu Server

Routes (non-default ones) can be added to the platform by using the interfaces configurations file.

Just add the following to the interface configuration:

up route add -net <destination_network> netmask <netmask> gw <gateway_address>

Example:

$ cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto ens160
iface ens160 inet static
        address 192.168.168.1
        netmask 255.255.255.0
        network 192.168.168.0
        broadcast 192.168.168.255
        gateway 192.168.168.254
        # dns-* options are implemented by the resolvconf package, if installed
        dns-nameservers 192.168.0.1
        dns-search mydomain.com
        up route add -net 172.16.16.0 netmask 255.255.255.0 gw 192.168.168.30
Posted on September 15, 2017 and filed under Linux, Tips'n Tricks.

Reset Apple macOS Spotlight

The macOS Spotlight service might loose its touch. E.g. when some applications or documents won't show up when you <CMD><SPACE> them. Reason could be that the service or its database got corrupt for some reason.

The following 4 commands will reset the Spotlight service and database. So after you issue those commands the PC/laptop will be re-indexed (which could take a while).

sudo mdutil -a -i off
sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
sudo mdutil -a -i on

Now, wait a bit, and everything should be back to normal.

Happy Spotlighting.

Posted on August 1, 2017 and filed under Apple, Operating Systems, Tips'n Tricks.

Think Tank Retrospective 7 with Macbook Pro 13" (late 2016)

Screen Shot 2017-04-04 at 11.12.23.PNG

The Think Tank Retrospective 7 camera bag holds an iPad, 11" Macbook Air or something similar according to the specifications. But the new Macbook Pro 13" (from late 2016), also fits (like a glove) in the back compartment of the bag.

It does take some effort in inserting the Macbook Pro for the first time. Especially if the bag is brand new. But after inserting it a couple of times, the fabric loosens a bit and it becomes easier to insert and extract the laptop from the compartment.

NOTE: There might be some scratching involved on the laptop over time while opening opening and closing the zipper (because of the 'fits-like-a-glove' thing).

Posted on April 4, 2017 and filed under Photography, Review, Gear, Tips'n Tricks.