Monday, April 17, 2017

HOWTO : Secure Surfing

According to OWASP Secure Headers Project, Secure Headers are setting response headers from the web server that can restrict modern browsers from running into easily preventable vulnerabilities.

The following are some of the Secure Headers description that from OWASP Secure Headers Project :

HTTP Strict Transport Security (HSTS)

"HTTP Strict Transport Security (HSTS) is a web security policy mechanism which helps to protect websites against protocol downgrade attacks and cookie hijacking. It allows web servers to declare that web browsers (or other complying user agents) should only interact with it using secure HTTPS connections, and never via the insecure HTTP protocol."

Public Key Pinning Extension for HTTP (HPKP)

"HTTP Public Key Pinning (HPKP) is a security mechanism which allows HTTPS websites to resist impersonation by attackers using mis-issued or otherwise fraudulent certificates."


"This header enables the Cross-site scripting (XSS) filter in your browser."


"Content Security Policy (CSP) requires careful tuning and precise definition of the policy. If enabled, CSP has significant impact on the way browser renders pages (e.g., inline JavaScript disabled by default and must be explicitly allowed in policy). CSP prevents a wide range of attacks, including Cross-site scripting and other cross-site injections."

When secure headers are set in the web servers, it is showing that the sysadmins/developers are concerning about the security of their clients/users. Most attacks, such as XSS and MITM attack, today are via browsers and targetted users.

We can learn more about the web servers response headers setting by using an online tool - Analyse your HTTP response headers. It is recommended to have Grade A or A+ for the testing. However, Grade B may be acceptable.

For the client side, it is recommended to install some add-ons or plugins for the browser security. Firefox is recommended as there are a lot of such kind of add-ons for the purpose. The following are the add-ons that to be recommended.


Allow active content to run only from sites you trust, and protect yourself against XSS and Clickjacking attacks.

* You are not required to enable it as it will block the javascript that most modern websites are using. You need to disable it globally to make the XSS attack protection by default.

uBlock Origin

Finally, an efficient blocker. Easy on CPU and memory. (Please refer to the official site for details)

WebRTC Control

Have control over WebRTC (disable or enable) and protect your IP address.

Self-Destructing Cookies

Self-Destructing Cookies automatically removes cookies when they are no longer used by open browser tabs. With the cookies, lingering sessions, as well as information used to spy on you, will be expunged. Websites will only be permitted to identify you while you actually use them and can not stalk you across the entire web. This is the closest you will get to cookieless browsing without breaking every second site or tedious micromanaging.

HTTPS Everywhere

Encrypt the web! HTTPS Everywhere is a Firefox extension to protect your communications by enabling HTTPS encryption automatically on sites that are known to support it, even when you type URLs or follow links that omit the https: prefix.

If you are a Ubnutu user, you can implement the Apparmor for Firefox to further hardening.

When both server side and client side are secured, it is very hard to be attacked by XSS and MITM attack or some other attacks.

Happy surfing!

That's all! See you.

Saturday, April 15, 2017

Green PadLock is Safe?

According to Wikipedia, HTTPS is only to encrypt the communication traffic between browsers and web servers in order to prevent Man-In-The-Middle (MITM) attack. HTTPS is not indicating that the websites are bearing a green padlock being "safe".

Many people are misinterpreted that if a website is bearing a green padlock with HTTPS URL, it is a "safe" website. The "safe" here is referring to the website that not doing any malicious activities against the users.

Recently, I read an article "When the 'S' in HTTPS also stands for shady". That is also showing that even information security guys and gals may misinterpreted the purpose of the HTTPS.

Since users can revoke and regenerate the Let's Encrypt SSL certificates themselves, to revoke the SSL certificate of malicious websites by Let's Encrypt is meaningless. Without Let's Encrypt, malicious hackers can purchase SSL certificate from others sources to complete the task without any problem.

Ten odd years ago, many experts stated that if the the browser is showing a locked padlock, you are "safe" and the website is "safe". It is misleading for sure.

We should educate the users that even the websites are looking legit and bearing a valid SSL certificate, they should think more before clicking any link on the site. It is because most phishing sites are looking legit and have valid SSL certificate. They should check the URL address of the website before going further especially for banking and payment sites. Beware of the website is being redirected to other URL too.

By the way, malicious hackers can impersonate the HTTPS traffic and doing MITM attack at ease today! No system is safe!

That's all! See you.

Wednesday, April 12, 2017

[RESEARCH] Information Security Scammers?

What Attracted Me

Recently, Nexus Guard and Zenedge catch my eyes. They provide similar products/services, such as DDoS Protection by Content Delivery Network (CDN) and Web Application Firewall (WAF).

Nexus Guard website saying that they are the leader in the market :

"As a longtime leader in DDoS defense, Nexusguard is at the forefront of the fight against malicious Internet attacks, protecting organizations worldwide from threats to their websites, services, and reputations."

Zenedge website provides a free vulnerability and threat assessment for their potential clients :

"The report is produced by our team of cybersecurity experts bring a collective 200 years of cybersecurity experience and have been responsible for mitigating some of the largest attacks. Ever."

Basic and Fast Research

I wonder why there are so many CDN providers recently. CDN requires a lot of proxies around the world in order to absorb very large amount of DDoS traffic. They need to invest a lot on the infrastructure. Therefore, I did some basic and fast research on them.

I find out that they both use Let's Encrypt free SSL/TLS certificates on their official websites. Meanwhile, their official websites are hosting (or domains hosting on proxy) on

I further find out that is registered by - Akamai. Akamai provides CDN and cloud computing services which is including WAF. She is one of the famous CDN and WAF providers in the market since 1998. I confirmed that is hosting (or hosting the domain on the proxy) on too on different IP address/subnet with Nexus Guard and Zenedge. Meanwhile, Nexus Guard and Zenedge are in the same subnet.

Nexus Guard

Nexus Guard conducted an unprofessional research on Android TV boxes with 3 popular anti-virus programs, such as Dr. Web and ESET in July 2014 and posted on a Hong Kong local magazine - East Week Vol. 568. They just posted the results of the scanning and misled the readers that some Android TV boxes are vulnerable to so-called backdoors. However, they did not confirm if the so-called backdoors are exploitable or not.

Nexus Guard also released an article about DDoS in May 2016 where they mentioned that DDoS by NTP is on the top of the list of the attacks. However, it seems that they do not know that the NTP attacks at that time is because of the zero day vulnerability on NTP protocol.

Most of their reports, threat advisories and whitepapers are restate the information security news that are all available in the public. Thinking of writing so many reports, threat advisories and whitepapers will make them more looking like a professional information security firm?


Since Zenedge provides free vulnerability and threat assessment on their website, I tried to contact the sales agent on the Zenedge site and he redirect me to contact Nelson Chen who is CISSP, CISA, CISM and Director Security Solutions of Zenedge. I requested a free vulnerability and threat assessment on my personal site on April 10, 2017 via direct email with Nelson. However, I did not have any reply from him since then (3 days at the time of this writing).

That make me thinking that they are pretending to provide free service in order to obtain information of their potential clients for their promotion purpose? Or, Neslon is thinking too much when an infosec (information security) guy is approaching them as they are thinking that their customers should be noob? Or, they do not have any professional infosec guy to do assessment on my personal site? Or, my personal site is too lame that they disdain to do the job?

Questions in Mind

If Nexus Guard and Zenedge have their own CDN and products/services, why their official websites are hosting (or hosting the domains on proxy) on Akamai? They do not believe that their products/services are better than Akamai? Nexus Guard and Zenedge are resellers/Value Added Resellers of Akamai? They are all information security scammers?


Think carefully before you purchase information security services or products. Do more researches on the providers/vendors of infosec before making any decision. Finally, it is difficult to determine professional and unprofessional in general.


Distributed Denial-of-Service Attack
Content Delivery Network
Web Application Firewall

(a) Nexus Guard -
Domain is registered on Sept 9, 2008
Server common name :
Server domain #1 : (
Server domain #2 : (
Server IP :

(b) Zenedge -
Domain is registered on Jan 7, 2013
Server common name :
Server domain #1 : (
Server domain #2 : (
Server IP :

(c) Akamai -
(Akamai Technologies -
Domain is registered on Aug 17, 1998
Server domain : (

That's all! See you.

Sunday, April 09, 2017

Catch Me If You Can 4

It is the fourth article in "Catch Me If You Can" series. The previous three articles were talking about how to prevent from being catch. However, this article is talking about once you have been arrested what can you do to prevent from being charged for hacking.

Once you have been arrested, your digital devices (such as personal computers, laptops, smartphones and other devices) should be seized. The "device" below is applied to Personal Computers and Laptops only. Laws enforcement would conduct digital forensic on all your devices in order to seek any evidence of cyber crime that you have conducted. However, if your devices are still switching on when you are arrested, laws enforcement would not turn your device off and would conduct the digital forensic right away.

You can use Bleachbit to delete all deleted files, logs and backups. However, some valuable files may not be deleted. Therefore, Bleachbit may not be a very good solution even it is good practice to use it for the purpose.

Offense Security's Kali Linux development team ported a Self-Destruction Luks encryption on Kali Linux since version 1.0.6 that allows the hard drive (or SSD) to be encrypted fully with normal and nuke passphrases. Once the nuke passphrase is entered, all the passphrase for the decryption will be deleted and the hard drive (or SSD) cannot be recovered. Therefore, the hard drive (SSD) is safe for being digital forensic. If you are not using Kali Linux for the hacking, you can apply self-destruction Luks encryption for some other Linux distributions.

It is recommended that the self-destruction nuke passphrase is much shorter than the normal passphrase in order to prevent your device from being brute forcing. Meanwhile, it is not recommended to backup your normal passphrases somewhere.

How about the device is still switching on? It is recommended to force turn off the device by long pressing the power button or unplug the power supply if you can while you are being arrested. Make sure you setup your device to turn off when the power button is long pressed instead of suspension.

Difference countries should have difference cyber crime laws. Even laws enforcement cannot get any evidence from your devices but you may be charged for other offences under the laws of your country.

That's all! See you.


Emergency Sef-destruction Luks in Kali
Luks and Nuke Key Installation on Ubuntu

See Also

Catch Me If You Can
Catch Me If You Can 2
Catch Me If You Can 3

Wednesday, March 29, 2017

HOWTO : Highest secured Hiawatha Web Server 10.5 on Ubuntu Server 16.04 LTS

(A) Introduction

Hiawatha Web Server is designed with security in mind. It already built-in some security features to protect common attacks, such as SQLi, XSS, CSRF. Meanwhile, it can be configured to prevent scanning from vulnerability scanners too.

Hiawatha is a light weight and fast as well as secure web server in the market. Hiawatha is working well with PHP and MySQL. The following guide is showing how to configure Hiawatha in a very high secure way on Ubuntu Server LTS.

(B) Software Prerequisite

The current version as at the time of this writing :
(1) Ubuntu Server 16.04.2 LTS
(2) CMake 3.7.2
(3) Hiawatha 10.5

(C) Installation of PHP7.0 and MySQL

sudo apt-get install php7.0-cgi php7.0 php7.0-cli php7.0-mysql php7.0-curl php7.0-gd php7.0-intl php7.0-imap php7.0-mcrypt php7.0-pspell php7.0-recode php7.0-sqlite3 php7.0-tidy php7.0-xmlrpc php7.0-xsl apache2-utils php7.0-fpm php-memcache php-imagick php-cache mysql-server mysql-client

(D) Installation of Hiawatha

sudo apt-get install libc6-dev libssl-dev dpkg-dev debhelper fakeroot libxml2-dev libxslt1-dev

(a) Install CMake

tar -xvzf cmake-3.7.2.tar.gz
cd cmake-3.7.2
sudo make install

(b) Install Hiawatha

tar -xzvf hiawatha-10.5.tar.gz

cd hiawatha-10.5/extra


cd ..

sudo dpkg -i hiawatha_10.5_amd64.deb

(E) Configuration of PHP7.0

sudo nano /etc/php/7.0/fpm/php.ini

Make changes as is.

allow_url_fopen = Off
session.cookie_httponly = 1
disable_functions = [EXIST_FUNCTION],system, show_source, symlink, exec, dl, shell_exec, passthru, phpinfo, escapeshellarg, escapeshellcmd,

* [EXIST_FUNCTION] is the functions that already at "disable_functions" of php.ini

(F) Let's Encrypt on Hiawatha

(a) Configuration of Hiawatha

sudo mkdir -p /etc/hiawatha/enable-sites
sudo mkdir -p /etc/hiawatha/disable-sites

Edit "cgi-wrapper.conf".

sudo nano /etc/hiawatha/cgi-wrapper.conf

Change the following as is.

CGIhandler = /usr/bin/perl
CGIhandler = /usr/sbin/php7.0-fpm
CGIhandler = /usr/bin/python
CGIhandler = /usr/bin/ruby
CGIhandler = /usr/bin/ssi-cgi

Wrap = jail_mysite ; /var/www/mysite ; www-data:www-data

Change the ownership of the log files.

cd /var/log/hiawatha
sudo chown www-data:www-data access.log
sudo chown www-data:www-data error.log
sudo chown www-data:www-data exploit.log
sudo chown www-data:www-data garbage.log
sudo chown root:root system.log

Change the ownership of the web application files.

cd /var/www/mysite
sudo chown -R root:root *

The following are examples of "hiawatha.conf" and "".

/etc/hiawatha/hiawatha.conf example :

/etc/hiawatha/enable-sites/ example :

(b) Self Signed SSL Certificate Generation

To generate SSL certificate for the web root.

openssl genrsa -out default.pem 4096
openssl req -new -x509 -days 3650 -key default.pem -out server.crt
echo "" >> default.pem
cat server.crt >> default.pem
echo "" >> default.pem
rm -f server.crt
sudo mkdir -p /etc/hiawatha/tls
sudo cp default.pem /etc/hiawatha/tls
sudo chown www-data:www-data /etc/hiawatha/tls/default.pem
sudo chmod 400 /etc/hiawatha/tls/default.pem
sudo chmod 400 -R /etc/hiawatha/tls

(c) Let's Encrypt Generation and Configuration

To generate SSL certificate for the

tar -xvzf letsencrypt.tar.gz
cd letsencrypt

nano letsencrypt.conf

Change the email "" to your email as Let's Encrypt bot will inform you about the expire date of the certificate :

Change the RSA Key size from "2048" to "4096" :

Uncomment "Production" and comment out "Testing" :
LE_CA_HOSTNAME = # Production
#LE_CA_HOSTNAME = # Testing

Make sure Port 80 is working and run the following command.

For the first time, you need to register to Let's Encrypt. Make sure keep the generated "account.key" in a safe place. "account.key" should be in the original place when doing SSL certificate renewal.

./letsencrypt register

To generate the SSL certificate.

sudo ./letsencrypt

To revoke the SSL certificate (Optional).

sudo ./letsencrypt /etc/hiawatha/tls/

To renew SSL certificate (Optional).

sudo ./letsencrypt renew

To get the Let's Encrypt X3 certificate at and select :

Let’s Encrypt Authority X3 (IdenTrust cross-signed)

echo "" >>
cat lets-encrypt-x3-cross-signed.pem.txt >>

echo "" >> default.pem
cat lets-encrypt-x3-cross-signed.pem.txt >> default.pem

To generate sha256 base64 hash of the certificates. The first one is the "" SSL certification and the second one is the SSL certification for web root directory.

openssl x509 -in /etc/hiawatha/tls/ -pubkey -noout | openssl rsa -pubin -outform der | openssl dgst -sha256 -binary | base64

openssl x509 -in /etc/hiawatha/tls/default.pem -pubkey -noout | openssl rsa -pubin -outform der | openssl dgst -sha256 -binary | base64

Then change "CustomHeaderClient = Public-Key-Pins:" values at "/etc/hiawatha/enable-sites/". The first "pin-sha256" is for "" and the second "pin-sha256" is for web root. The others "pin-sha256" are get from Qualys SSL Labs Test site (see below).

With the help of Qualys SSL Labs, you can further configure the HPKP and test the grading of your site. The highest grade is A+.

The grade of the site are A+ on both Qualys SSL Labs and High-Tech Bridge SSL certificate testings. Meanwhile, it is also compliance with PCI DSS 3.1 Requirements that reported by High-Tech Bridge.

The Let's Encrypt SSL Certificate will be expired about 28 days and it requires to be renewed. Make sure you update "CustomHeaderClient = Public-key-Pins:" at /etc/hiawatha/enable-sites/ (as example). The first "pin-sha256" is required to be updated. After that, restart Hiawatha.

(G) Hardening of Ubuntu Server

(a) sysctl

sudo nano /etc/sysctl.d/60-hiawatha.conf

sudo sysctl /etc/sysctl.d/60-hiawatha.conf -p

(b) Apparmor

sudo apt-get install apparmor-profiles apparmor-utils
sudo nano /etc/apparmor.d/usr.sbin.hiawatha

sudo aa-enforce hiawatha

If you have change some settings, you should reload the profile.

sudo apparmor_parser -r < /etc/apparmor.d/usr.sbin.hiawatha

If you want to disable this profile.

sudo ln -s /etc/apparmor.d/usr.sbin.hiawatha /etc/apparmor.d/disable/
sudo apparmor_parser -R < /etc/apparmor.d/usr.sbin.hiawatha

If you want to re-enable this profile after it has been disabled.

sudo rm /etc/apparmor.d/disable/usr.sbin.hiawatha
sudo apparmor_parser -r < /etc/apparmor.d/usr.sbin.hiawatha

Remarks :

If you encounter "500 Internal Server Error", you may consider to make the Apparmor to "Complain mode".

sudo aa-complain hiawatha

After several days browsing the website, you may consider to turn the Apparmor to "Enforce mode".

sudo aa-logprof

sudo aa-enforce hiawatha

It is because the captioned usr.sbin.hiawatha may not 100% work for you.

(c) Linux Malware Detect (Optional)

Linux Malware Detect Installation

* the captioned link may be out-dated and it is for your reference only

(d) MySQL

Create Normal User on MySQL

(e) fail2ban

sudo apt-get install fail2ban

Change the setting at /etc/fail2ban/jail.conf when necessary.

(H) Storage Performance Tuning

It is recommended to use SSD for the storage instead of hard drive for the excellent performance.

(a) SSD

Verify TRIM is supported :

sudo hdparm -I /dev/sda | grep TRIM

If the output is similar to the below which is supported :

* Data Set Management TRIM supported (limit 1 block)

If you install your Ubuntu in LVM, the TRIM is usually enabled by default. You can confirm it :

cat /etc/lvm/lvm.conf | grep issue_discards

If the output is similar to the below which is enabled :

issue_discards = 1

Then set the following to "deadline" if it is not done yet.

cat /sys/block/sda/queue/scheduler

noop [deadline] cfq

If not, set it :

sudo nano /etc/rc.local
Insert the following before "exit 0" :

echo 2048 > /sys/block/sda/queue/read_ahead_kb
echo 2048 > /sys/block/sda/queue/nr_requests
echo deadline > /sys/block/sda/queue/scheduler

* make sure your device is sda (or sdb ...)

To reload it or reboot your system :

sudo bash /etc/rc.local

After that, you need to edit the partition table (/etc/fstab) :

To make it looks like the following :

/dev/mapper/ubuntu--vg-root / ext4 noatime,nodiratime,norelatime,errors=remount-ro 0 1

sudo mount -a
sudo mount -o remount /

If you have an error after running the captioned commands, DO NOT reboot your system. You should correct the typo before doing so; otherwise, you cannot boot to your system again.

(b) Hard Drive

sudo nano /etc/rc.local

Insert the following before "exit 0" :

echo 2048 > /sys/block/sda/queue/read_ahead_kb
echo 2048 > /sys/block/sda/queue/nr_requests

* make sure your device is sda (or sdb ...)

To reload it or reboot your system :

sudo bash /etc/rc.local

After that, you need to edit the partition table (/etc/fstab) :

To make it looks like the following :

ext4 noatime,nodiratime,norelatime,errors=remount-ro 0 1

sudo mount -a
sudo mount -o remount /

If you have an error after running the captioned commands, DO NOT reboot your system. You should correct the typo before doing so; otherwise, you cannot boot to your system again.

(I) Optional

To further hardening Ubuntu Server, you may consider to set up firewall (UFW/iptables) and place the Ubuntu Server behind Unified Threats Management System (UTM) or Intrusion Prevention System (IPS).

Qualys SSL Labs
High-Tech Bridge
URL Rewrite for Hiawatha

That's all! See you.

Monday, March 06, 2017

HOWTO : Install Go Language 1.8 on Ubuntu 16.04 LTS

The current Go version is 1.6 on Ubuntu 16.04. However, the official Go version is 1.8 as of this writing. We need to install Gophers Ubuntu PPA to complete the task.

Step 1 :

sudo add-apt-repository ppa:gophers/archive
sudo apt-get update
sudo apt-get install golang-1.8

Step 2 :

The workspace is "go" at your working directory by default (such as /home/samiux/go).

nano ~/.profile

Append the following lines at the end of the file :

export PATH=$PATH:/usr/lib/go-1.8/bin

Step 3 :

Log out and re-login.


source ~/.profile

Step 4 :

To test if it is working properly :

go version
go env

Step 5 :

Make sure you create the following directories at the "go" workspace :

mkdir -p ~/go/bin
mkdir -p ~/go/src

You build your project, for example "erp", at "~/go/src/erp".

That's all! See you.

Wednesday, March 01, 2017

HOWTO : Watching China and Hong Kong Online TV on Ubuntu Desktop 16.04 LTS

Step 1 :

sudo dpkg -i getdeb-repository_0.1-1~getdeb1_all.deb

sudo apt-get update
sudo apt-get install youtube-dl

Step 2 :

sudo add-apt-repository ppa:djcj/vapoursynth
sudo apt-get update
sudo apt-get install mpv

(A1) Watch CCTV (China) [Most Updated Method]

If you select this method, you are NOT required to do the "Step 1" and "Step 2".

The "CNTVLive2 plugin for 64BitLinux v2.0.0.3" is updated on March 3, 2017 and it solved the force close problem. It plays CCTV Online TV smoothly. After the plugin is installed, you need to bypass the signed add-on problem by using the following way.

WARNING : After doing the following steps, you have a RISK to install malicious Firefox add-on by accident!

At the URL field at the Firefox, type :


Look for the following and double click it to turn it to "false" :


You can click on one of the following links to install the plugin when prompted.

CCTV Live Channel 1
CCTV Live Channel 2
CCTV Live Channel 3
CCTV Live Channel 4
CCTV Live Channel 5
CCTV Live Channel 6
CCTV Live Channel 7
CCTV Live Channel 8
CCTV Live Channel 9
CCTV Live Channel 10
CCTV Live Channel 11
CCTV Live Channel 12
CCTV Live Channel 13
CCTV Live Channel 14
CCTV Live Channel 15
CCTV Live Channel 5+

* make sure Flash is installed and enabled
* some channels are copyrighted and only plays in China Region

(A2) Watch CCTV (China) [Outdated Method]

If you select this method, you need to do "Step 1" and "Step 2".

You need to install Firefox add-ons, namely watch-with-mpv.

CCTV Live Channel 1
CCTV Live Channel 2
CCTV Live Channel 3
CCTV Live Channel 4
CCTV Live Channel 5
CCTV Live Channel 6
CCTV Live Channel 7
CCTV Live Channel 8
CCTV Live Channel 9
CCTV Live Channel 10
CCTV Live Channel 11
CCTV Live Channel 12
CCTV Live Channel 13
CCTV Live Channel 14
CCTV Live Channel 15
CCTV Live Channel 5+

Optional settings :
Preferences -- Additional playr parameters
--buffer-size 2048 --no-check-certificate --skip-unavailable-fragments --sleep-interval 0.05 --max-sleep-interval 0.5 --limit-rate 2M

* make sure Flash is installed and enabled
* some channels are copyrighted and only plays in China Region

(B) Watch ViuTV (Hong Kong)

If you select this option, you need to do "Step 2" only.

nano viutv

Append with the following content and save it.

To run :



That's all! See you.

Friday, February 10, 2017

HOWTO : Ajenti 1.x on Ubuntu Server 16.04 LTS

Ajenti is an Admin Control Panel for your Linux server. However, Ajenti 2.x is buggy and it is not working properly when I am testing it. Fortunately, Ajenti 1.x still working for Ubuntu 16.04 LTS even it's documentation is written for Ubuntu 12.04.

You can access your Linux server via web browser instead of SSH.

Step 1 :

wget -O- | sudo apt-key add -

Step 2 :

sudo touch /etc/apt/sources.list.d/ajenti.list
echo "deb main main ubuntu" | sudo tee -a /etc/apt/sources.list.d/ajenti.list

Step 3 :

sudo apt-get update && sudo apt-get install ajenti

sudo systemctl restart ajenti

Step 4 :

To access Ajenti, you open the broswer and point it to your server IP. Username is "root" and password is "admin".


That's all! See you.

Tuesday, February 07, 2017

HOWTO : Optimize Ubuntu 16.04 LTS and Kali Linux 2016.2 with jemalloc

jemalloc is a general purpose malloc(3) implementation that emphasizes fragmentation avoidance and scalable concurrency support. It is the best allocators for a broad range of demanding applications, and eliminating/mitigating weaknesses that have practical repercussions for real world applications.

Step 1 :

Option 1 : Compile from source (latest version)

*** This option is not recommended for Ubuntu 16.04 LTS Desktop and Kali Linux 2016.2. When using in Ubuntu 16.04 LTS Desktop, Firefox will be crashed when 2 or more instances are opened. Meanwhile, Kali Linux 2016.2 requires redis-server which is using stock version of libjemalloc1 by default. redis-server for Ubuntu 16.04 also requires stock version of libjemalloc1.

git clone
cd jemalloc
make dist
sudo make install

The final files "libjemalloc.*" are located at "/usr/local/lib/".

touch /etc/

echo "/usr/local/lib/" | sudo tee --append /etc/

Option 2 : Install package (usually older version)

This option is recommended for Ubuntu 16.04 LTS and Kali Linux 2016.2.

sudo apt-get install libjemalloc1 libjemalloc-dev

The final files "libjemalloc.*" are located at "/usr/lib/x86_64-linux-gnu/".

touch /etc/

echo "/usr/lib/x86_64-linux-gnu/" | sudo tee --append /etc/

sudo ln -s /usr/lib/x86_64-linux-gnu/ /usr/lib/x86_64-linux-gnu/

Step 2 :

Reboot your box.

Step 3 :

To confirm it is running properly (for example, firefox is running with it) :

sudo lsof -E | grep libjemalloc | grep firefox

That's all! See you.

Thursday, January 26, 2017

HOWTO : Configure Network Interface For Better Performance on Ubuntu 16.04 LTS

Intel network interface card is configurable. Some other brands can but Realtek do not.

(0) You need to install ethtool if it is not :

sudo apt-get install ethtool

(1) List out the available network interface on your system :

ls /sys/class/net

enp1s0f0 enp1s0f1 enp7s0 enp8s0 lo

(2) To see if the network interface can pause the transmission when neccessary or not in order to prevent packet drop :

ethtool -a enp1s0f0

Pause parameters for enp1s0f0:
Autonegotiate: on
RX: on
TX: on

If the values are not "on", you can set it to :

sudo ethtool -A enp1s0f0 rx on tx on

(3) To see if the buffer is at the maximum value or not :

ethtool -g enp1s0f0

Ring parameters for enp1s0f0:
Pre-set maximums:
RX: 4096
RX Mini: 0
RX Jumbo: 0
TX: 4096
Current hardware settings:
RX: 4096
RX Mini: 0
RX Jumbo: 0
TX: 4096

If the current hardware settings values are not as the Pre-set maximums, you can set them to be :

sudo ethtool -G enp1s0fo rx 4096 tx 4096

(4) If your network interface cannot be configure like Intel, you may see the following result :

ls /sys/class/net

enp2s0 enp3s0 lo wlp4s0

ethtool -a enp2s0

Pause parameters for enp2s0:
Cannot get device pause settings: Operation not supported

(5) Finally, you can put those commands at /etc/rc.local and run the following command to activate the values :

sudo bash /etc/rc.local

That's all! See you.

Thursday, December 29, 2016

HOWTO : Configure OpenVPN on Ubuntu 16.04

There is a very good article by Digital Ocean for setting up OpenVPN on Ubuntu 16.04. After the above setup, you are required to further configure it to make it working properly.

The following additional settings is to allow all VPN clients can use the same certificate to login the VPN server. Meanwhile, it also allow the maximum concurrent users to 100.

sudo nano /etc/openvpn/server.conf

Uncomment (remove ";") the following :


max-clients 100

That's all! See you.

Wednesday, December 28, 2016

HOWTO : Build An Affordable Intrusion Detection And Prevention System For Home Users

What is Intrusion Detection And Prevention System?

Intrusion detection and prevention system (IDPS) monitors incoming and outgoing traffic on your network and blocks the malicious traffic (packets) based on rules (blacklists).

Why home users need IDPS?

Not only big companies need IDPS but also home users as long as they are connecting to the internet. Almost all home users installed anti-virus but it is not enough. They do need more protection against the cyber criminals.

However, most IDPS appliances are very expensive for home users. Most open source solutions are also demanding for them as they do not familiar with networking and technology.

What is Almond Croissants and Why?

Almond Croissants is an open source intrusion detection and prevention system which is based on Suricata engine. Suricata is the next-generation IDPS engine with a lot of outstanding features.

Users of Almond Croissants are not required to be familiar with networking and technology. It is designed for them in mind. Not only that, it is designed for low-end hardware too. It is really "Plug, Play and Forget!".

What are the key features of Almond Croissants?

- Block ports and vulnerabilities scanning
- Block known exploitation on vulnerable systems
- Block known malicious IP addresses to access your systems
- Block known source of Secure Shell (SSH) brute forcing
- Block The Onion Router (TOR) to access your systems
- Prevent from accessing known malicious sites with Secure Sockets Layer (SSL) certificates
- Prevent from being infected by known virus and malware
- Block known annoying advertising servers
- Easy and straight forward analysis with charts on web interfaces
- Compatible with Bittorrent and 4K video streaming
- Ultra-low latency for online gaming
- Compatible with Windows, Linux, macOS, Apple iOS and Android
- Ultra-low latency throughput that drives your network to a limit
- No subscription fee
- More protection for web servers
- More protection from known malware
- Block known phishing sites
- Automatically update and upgrade
- Plug, Play and Forget!

What hardware is required?

If you have a small family with 4 members and have about 200-250Mbps bandwidth, Zotac Mini PC CI323 (Intel Celeron N3150 with 16GB RAM) is recommended. Meanwhile, you may also require a USB 3.0 Gigabit Ethernet dongle. Yes, 16GB RAM. The vendor states that it supports up to 8GB RAM, however, you can install a total of 16GB RAM on it. A 320GB hard drive is also required. It requires a total of 3 network interface cards. The price of the system is below $400-USD. It is low power consumption for long run.

More powerful CPU and more memory are recommended for demanding situation. Almond Croissants is running on dedicated hardware. The minimum requirements for Almond Croissants is 2-4 CPU threads and 16GB RAM.

How to install?

Since ultra-low latency of Almond Croissants, it is recommended to put Almond Croissants between modem and router. Furthermore, you can install it between router and switch too. However, if you have a wireless router, it is recommended to put Almond Croissants in front of the wireless router.

First of all, you need to install Ubuntu Server (LTS edition) on the box. SSH server is recommended to be installed for remote management inside your network. It may need 8 or more hours to install Almond Croissants on Zotac Mini PC CI323. Make sure the box is connecting to the internet as it fetches the packages and data from various servers in the internet.

The installation procedure is well documented on the Almond Croissants official site. It is easy but it kills time.

After the installation, you can plug the Zotac Mini PC CI323 between modem and router. The USB Ethernet Card is connecting to switch. A reboot is required. It needs about 10 minutes to let all the rules and data load into the memory once boot up.

What's next?

Make sure firewall on your router is enabled and do not allow SSH port to be accessed outside your network unless it is well protected. Anti-virus program to be installed on every computer is optional but is recommended.

For further protection on your laptop and smartphone outside your home, you are required to setup a VPN inside your network. When you are using laptop at coffee shop or using smartphone on the road, you can connect to your VPN and your connection will be protected by Almond Croissants.

All rules and upgrade will be conducted during mid-night between 0100 and 0800 hours. Therefore, the box requires running 24/7/365 and server grade hardware is recommended.

See also

Almond Croissants - Intrusion Detection And Prevention System
Zotac Mini PC C Series
Suricata IDPS Engine
Hardening Mobile Devices with Intrusion Prevention System
Know Your Enemies and Know Yourself
OpenVPN official site
How To Set Up an OpenVPN Server on Ubuntu 16.04
Configure OpenVPN on Ubuntu 16.04
Intel Celeron N3150 Specifications

That's all! See you.

Tuesday, December 13, 2016

Know Your Enemies and Know Yourself


Sun Tzu's The Art of War (孙子兵法) says "If you know your enemies and know yourself, you will not be put at risk even in a hundred battles. If you only know yourself, but not your opponent, you may win or may lose. If you know neither yourself nor your enemy, you will always endanger yourself." (知彼知己,百战不殆;不知彼而知己,一胜一负;不知彼,不知己,每战必殆。) [source : Wikipedia]

Sun Tzu's The Art of War also says "All warfare is based on deception. Hence, when we are able to attack, we must seem unable; when using our forces, we must appear inactive; when we are near, we must make the enemy believe we are far away; when far away, we must make him believe we are near." (兵者,诡道也。故能而示之不能,用而示之不用,近而示之远,远而示之近。) [source : Wikipedia]


Most internet attack activities based on recon on the target. Recon can be conducted by active and passive methods. Active recon will cause a lot of noise to the target as it will collect information from the target directly while passive recon does not.

Once attackers gathered valuable information about the target, such as running services and versions on the target. They will launch exploits when there are vulnerable services running on the target. Once success, the target will be compromised and under the control of the attackers.

On the other hand, if there is no running vulnerable services on the target, attackers may launch social engineering attacks against the target, such as phishing mails, phishing sites, phishing phone calls, phishing downloads and etc. Social engineering may lead to compromise of the target as a result.

The captioned mention attacks can be based on randomly selected target or targeted victim. Furthermore, some attacks are directly by botnets which randomly selecting the targets and aimed to the vulnerable running services. Botnet attacks also have active recon stage as mentioned before.

Possible Defense

Besides some of social engineering attacks, we all know that all almost all attacks are following by recon. If attackers cannot get any valuable information from us, we can delay or even prevent the attack.

We all know that nmap can obtain information of the running services on the opening ports. If we can block nmap scanning from the beginning, attackers are required to guess which ports are opened and which services and versions are running on that ports. They cannot go further when they have no valuable information about us. If so, we can delay or even prevent the attacks. However, social engineering attacks may be launched soon by the attackers.

Commercial Solution

Some anti-virus for Windows system and some Unified Threats Management System (UTM) as well as some Intrusion Prevention System (IPS) can block port scanning. However, some of them failed to detect and block the nmap scan when it is scanning with special command flags. Meanwhile, anti-virus software and UTM as well as IPS may require to subscribe the signatures annually. In addition, commercial UTM and IPS are very expensive. It may cost a lot when long run.

Open Source Solution

Suricata and Snort are very famous Intrusion Detection and Prevention engines (IDPS). They are running based on blacklisting. Those blacklists are rules to alert or block the traffic when the traffic meets the criteria. There are open rules and paid rules available in the market. Some IDPS engines users can write their own rules to meet their requirements. However, some of the rules are written wrongly that causing false positive alert or even cannot detect the activities.

Not everyone is IDPS expert. Setting up a working Suricata or Snort appliance is painful. Users are required to troubleshoot all the problems that they are encountered. Sometimes are hardware limitations. Sometimes are false positive alerts/drops. Sometimes are IDPS engines limitations.

Plug, Play and Forget!

Almond Croissants is an open source IDPS based on Suricata engine. It is released under GPLv3 by Samiux since 2012. It is well tested on Windows, macOS, Linux, Apple iOS and Android. Engine and rules are updated automatically when they are available. Users are not required to be very familiar with IDPS. It not only can detect and block nmap scanning without pain but also have many outstanding features that most IDPS omitted. It is tasty and really "Plug, Play and Forget!"

That's all! See you.

Monday, December 12, 2016

HOWTO : Traffic and Attack Map for Suricata

"Traffic & Attack Map for Suricata" is forked from Matthew May's Attack Map at GitHub

"Traffic & Attack Map for Suricata" is modified to work with Suricata's eve.json file. It shows the inbound traffic only which includes normal and attack traffic. It is designed for Python 3 and Ubuntu Server 16.04 LTS. It is also designed to install on the box of Suricata.

The map shows "DROP" or "ALERT" when the traffic is dropped or alerted by Suricata. Meanwhile, other traffic will be shown as its nature (Event Type), such as DNS, TLS, FILEINFO and etc.


"Traffic & Attack Map for Suricata" is released under GPLv3 by Samiux.


(1) Working Suricata dedicate server as IDPS on Ubuntu Server
(2) Python 3.x
(3) Web server with websocket function
(4) Redis server


sha256sum fda369bd246048ce883fabb16e085caa022a492a7e188b4f0c99f37ea4bc8bdb attack-map-0.0.1.tar.gz


Step 1 :

sudo apt-get install python3-pip redis-server
sudo pip3 install tornado tornado-redis redis maxminddb

sudo nano /etc/redis/redis.conf

Change from :

To :

Step 2 :

tar -xvzf attack-map-0.0.1.tar.gz
cd attack-map/geoip-attack-map

cd ..
sudo cp -R geoip-attack-map /var/www

Step 3 :

cd ..
sudo cp attackmap.service /lib/systemd/system/
sudo cp dataserver.service /lib/systemd/system/

sudo systemctl enable attackmap.service
sudo systemctl enable dataserver.service

Step 4 :

cd /var/www/geoip-attack-map/DataServer
sudo nano

Go to :
hq_ip = '' replace "hq_ip" with your external IP address.

cd /var/www/geoip-attack-map/AttackMap
sudo nano trafficline.js

Go to :
var webSock = new WebSocket("ws://");

replace the "" with your Suricata IP.

Go to :
var hqLatLng = new L.LatLng(33.936051, -81.048565);

replace the value of L.LatLng with your location. You can go to to find your Latitude and Longitude values.

Then configure your web server to point the root directory to "/var/www/geoip-attack-map/AttackMap". Make sure you have enabled "websocket" module or function on your web server. Meanwhile, the port for the websocket is 8888 by default.

*** Setting up web server to work with this project is out of scope of this guide.

Step 5 :

Since Redis server requires this setting to avoid performance issue, you need to edit the boot parameter in Grub.

sudo nano /etc/default/grub

sudo update-grub

sudo reboot

Step 6 :

Once boot up, you can point your browser to the IP address that you entered in the above steps.


If there is no traffic on the map, it is properly the not working. Restart it is required.

sudo systemctl restart dataserver

*** Please note that it needs time to read the eve.json file from the beginning of the file on every restart.

Please also note that do not refresh or reload the page as it will corrupt the map. You need to restart the browser.


Traffic and Attack Map for Suricata

That's all! See you!

Wednesday, November 23, 2016

HOWTO : EveBox on Almond Croissants and Danish

EveBox is a web based Suricata "eve" event viewer for ElasticSearch. ElasticSearch is installed on Almond Croissants or Danish by default. However, EveBox is not installed by default. You need to install it yourself.

Almond Croissants is an Intrusion Detection and Prevention System while Danish is an Intrusion Detection System. Almond Croissants and Danish are created based on Suricata by Samiux under GPL version 3.

In general speaking, EveBox is for advanced Almond Croissants or Danish users.

Step 1a :

sudo cp evebox-0.5.0-linux-amd64/evebox /usr/bin/


Step 1b :

wget -O
sudo cp evebox-0.6.0dev-linux-amd64/evebox /usr/bin/

Step 2 :

sudo nano /lib/systemd/system/evebox.service

Description=EveBox Web Interface

ExecStart=/usr/bin/evebox -e http://localhost:9200


Step 3 :

sudo systemctl enable evebox.service
sudo systemctl start evebox.service

To access it, use your browser to surf :

http://[Almond Croissants IP address]:5636

Update or Upgrade

sudo systemctl stop evebox.service

Repeat Step 1a or 1b.

sudo systemctl start evebox.service

That's all! See you.

Sunday, November 13, 2016

[Review] MIUI 8

To more understand the features of MIUI 8, you need to watch this video.

That's all! See you.

Wednesday, November 09, 2016

[Review] Xiaomi Redmi Note 4

Briefed Specifications

CPU : MTK Helio X20 2.1GHz (10-core)
Storage : 64GB
GPU : Mali T880 MP4 700MHz
Display : 5.5 inches
Resolution : 1080x1920 pixels
Case : Metal
Battery : 4100mAh
Mobile : 4G/LTE (dual SIM or SIM with microSD)
OS : Android 6.0
NFC : Nil

Xiaomi Redmi Note 4 is a China brand Android smartphone which is released in October 2016. It's user interface is MIUI 8. Redmi Note 4 has the following outstanding features :

(A) Anti-Virus

It is pre-installed with anti-virus apps and you can choose either "AVL" or "Tencent" definitions. Meanwhile, you can choose both of them too. If you enabled "Scan before installing", all apps will be scanned before installing. The virus definitions will be updated automatically.

(B) Backup and Restore

By default, "Mi Account" is not enabled. You need to register an account. When you registered, your phone will be fully backup to "Mi Cloud" automatically. Meanwhile, you can restore from "Mi Cloud" when necessary.

(C) Featured tools

Some tools are pre-installed, such as real "FM Radio", barcode "Scanner", audio "Recorder", "Compass" which are grouped at "Tools" icon. Furthermore, "Mi Remote" which is an IR remote controller for TV or similar. "Mi Remote" is grouped at "More Apps" icon. In addition, "Mi Mover" which is situated at "Settings" >> "Additional settings" can move apps and data from old phone (Xiaomi for sure) to new Xiaomi phone.

(D) Blacklist

You are not required 3rd party blocker for the telephone and SMS as it is pre-installed and it is situated at "Security" icon. It can block by telephone number, telephone number prefix or contacts.

(E) Quick ball

A quick access and customizable button on the screen (you can move it anywhere on the screen). It is disabled by default. You can enable it by "Settings" >> "Additional settings" >> "Quick ball". Once it is enabled, the default "Quick ball" has "Home", "Menu", "Lock", "Screenshot" and "Back". You can customize it at your will.

(F) Other features

It has some other features, such as "Lite mode" for elderly, "Second Space" for one phone with two different settings. It likes that you have two devices on one phone. "Second Space" is situated at "Settings". You can unlock the phone with your fingerprint. In addition, it can clear the cache when the phone is locked for a certain time, such as 30 minutes by default for battery saving.

(G) Special features

You need to use default "Clock" apps instead of installing Google's one. Otherwise, the alarm will not activate automatically.

Since it will kill apps for a certain time (3 days by default) in order to free up the memory, some apps that sending notification to other device (such as sports watch) via bluetooth will be dropped after the auto-clean. Meanwhile, when your phone is locked for 30 minutes (default), the battery saving function will clear the cache. However, it will also kill the running apps that sending notifications. Therefore, you need to configure it as at here manually. By the way, it does not come with NFC.

(H) MIUI 8 Review In-Depth

The review of MIUI 8 is here

That's all! See you.

Monday, November 07, 2016

HOWTO : Redmi Note 4 with Garmin fenix 3 HR Notification

Redmi Note 4 is new released China brand Android smartphone. Since MIUI 8 user-interface will kill the Apps in the memory in a certain time (such as 3 days by default), your Garmin fenix 3 HR will not receive any notification (such as Telegram or Whatsapp) via Redmi Note 4 after the auto clean up.

However, this default settings can be changed and the notifications will working.

Option 1 (Stupid way) :

(1) Security icon >> Settings >> Cleaner >> Clean automatically >> Items to clean

Disable "Cache", "Packages" and "Residuals".

(2) Security icon >> Settings >> Scan app memory


(3) Security icon >> Settings >> Battery usage >> Clear cache when device is locked

Set to "Never".

(4) Security icon >> Permissions >> Autostart

Enable "Connect", "Telegram" or "Whatsapp", "Voice Caller ID".

(5) Connect icon >> Settings >> Smart Notifications

Add and enable "Telegram" and/or "Whatsapp".

(6) Settings icon >> Bluetooth

Make sure fenix 3 HR is paired with the phone and bluetooth is enabled.

Option 2 (Smart Way) :

(A) Tap on the "Menu" key at the left bottom corner on the phone. Some running apps screens will be displayed. Swipe down the app screens (such as "Connect", "Telegram", "Whatsapp", "Voice Caller ID") and select "Lock" to prevent the apps from being killed by "Cleaning" feature. The "locked" apps will be running in the background unless you unlock it.

(B) Connect icon >> Settings >> Smart Notifications

Add and enable "Telegram" and/or "Whatsapp".

(C) Settings icon >> Bluetooth

You may also need to do the following for some apps :

(D) Security icon >> Permissions >> Autostart

Enable "Connect", "Telegram" or "Whatsapp", "Voice Caller ID".

Make sure fenix 3 HR is paired with the phone and bluetooth is enabled.

That's all! See you.

Monday, October 10, 2016

[RESEARCH] Cloudflare Can Be Bypassed

About two years ago, CEO of Cloudflare (cloud based Content Delivery Network, CDN) visited Hong Kong to promote their services after an unofficial referendum site (hosted by anti-government party), which is protected by Cloudflare, is under DDoS attack with about 400GB traffic. From that day, Cloudflare is well known to all anti-government parties in Hong Kong. Most of their websites are then protected by it.

This cloud based CDN service provides DDoS protection and the real IP address of the websites are hidden by purpose. Cloudflare has free and paid plans. The paid plan is equipped with Web Application Firewall (WAF). However, this plan is not cheap, so some of the anti-government websites are not in the plan.

When you google the keyword "cloudflare bypass", it returns a lot of pages that are mentioning how to find out the real IP address of the websites that protected by Cloudflare. However, most websites are configured not to present their content properly when browsing it with IP address. Therefore, to find out the real IP address of the website is not the way to bypass Cloudflare unless you want to attack the web server instead of the web application. Meanwhile, to find out the real IP address of the web servers are not easy as it is hidden properly recently.

To pentest those sites, you cannot use Web Vulnerability Scanners, that without WAF evasion feature, as they will be blocked. WAF evasion features for the scanners are not common in the market. You need to pentest those sites manually. Once you find something interesting and suspect it is vulnerable to SQL injection, you need to confirm it with other SQLi takeover tools, such as SQLMap. No matter it is pentesting by manual or SQLMap, you need WAF evasion skill to complete.

Meanwhile, Wordpress is very famous in Hong Kong too. If the target is a Wordpress site, make sure you do not use WPScan to scan it as your IP address will be banned for sure. Once your IP address is banned, you are no way to do the pentesting.

I conduct a research for bypassing Cloudflare with SQLMap and it is successfully with WAF evasion technique. No matter it is free or paid plan, Cloudflare can be bypassed for sure. I am not working for Cloudflare and I do not want to get any bounty. Therefore, I am not going to share my detailed research here as it will alert Cloudflare to improve their WAF when it is disclosed. I am sure that some other researchers out there are already bypassed Cloudflare too. Meanwhile, other OWASP Top 10 and other cloud based WAFs are not tested in this research.


(1) Cloudflare
(2) OWASP Top Ten Project

That's all! See you.

Thursday, September 22, 2016

HOWTO : Hardening Mobile Devices with Intrusion Prevention System

The internet security of mobile devices (such as smartphone, tablet and laptop) becomes very important today. How to secure them is a big problem. Since the cost of anti-virus per device is not cheap per month, most users installed free version of such apps (or programs). However, free version protects the devices on demand purpose only. When you have many mobile devices, you will push your hairs out to secure them. Meanwhile, anti-virus apps (or programs) are designed to prevent your devices from being infected by malware only. They cannot protect you from being attacked by web based attacks, such as Cross-Site Scripting (XSS) and Phishing attacks.

Not all browsers can protect you from being attacked by XSS and phishing by default or by plugins. Most Unified Management Systems (UTM) (or namely Next Generation Firewall) are equipped with anti-virus, spam blocker, web filter, advertising blocker, firewall, intrusion prevention and phish blocker. However, not all UTMs have a good intrusion prevention system.

Not all Intrusion Prevention Systems (IPS) can detect XSS, Phishing, spam, virus, advertising and web filtering. If you have a UTM or IPS that have all the mentioned protection, you can secure your mobile devices by installing a VPN server, such as OpenVPN. Some UTMs have VPN but it does not allow users to connect to the internet from it.

Mobile devices connect to your network, which is hardening by UTM or IPS, via VPN. The mobile devices can surf the internet just like inside your network. As a result, the mobile devices are protected by the UTM or IPS as well.

Open Source project, Almond Croissants, is an Intrusion Prevention System that has all the captioned protection. However, it is not a silver bullet. As I always say, "The risk is not your system vulnerable, the risk is you think that your system is secured".

By the way, make sure you disable the sharing function on your mobile device if any.


(1) Almond Croissants - Intrusion Detection and Prevention System
(2) How To Set Up an OpenVPN Server on Ubuntu 16.04

That's all! See you.