Use privoxy and Tor for increased anonymity

Tor protects you by bouncing your communications around a distributed network of relays run by volunteers all around the world: it prevents somebody watching your Internet connection from learning what sites you visit, and it prevents the sites you visit from learning your physical location (from https://www.torproject.org/).

There are Tor Bundles that you can install but you can also chain Tor through a proxy.

I’ll use an Ubuntu 1214 vmware machine to proxy my traffic.Read more.

What to do if your website gets hacked or defaced

Websites get attacked daily. Sometimes the attacker succeeds in accessing the website. This is often told as “we got hacked” but in most cases a “our website got defaced is more accurate.

This post describes what you have to do if you control your website (a custom build website or a CMS website build with Drupal, Joomla, WordPress, …) via FTP and you do not have a shell account on your server.

In most casesRead more.

Elasticsearch dynamic scripting vulnerability exploit

Update 20140716

“This could allow an attacker to execute OS commands.”. That is the notice on the security page of Elasticsearch.

A vulnerability that allows execution of system commands should always raise concern.

Some people running a public Elasticsearch instance reported cases where attackers were able to upload scripts. It turned out that when Elasticsearch was available on the Internet (port tcp/9200) and had dynamic scripting enabled then users could execute arbitrary scripts.Read more.

Automatic Check of Expiration Date of GPG keys

After Heartbleed I wrote a small python script to have an automatic check of certification expiration date. The script is hosted on Github.

Next to SSL certificates there are also GPG keys that can (but do not have to) have an expiration date. If you manage a lot of (personal or shared) keys it can become difficult to keep track of expired or soon to be expired keys.

So I wrote a similar python scriptRead more.

Automatic Check of Expiration Date of Certificates

After Heartbleed and generating lots of different new certificates I searched for a tool that sends me an alert when a certificate is about to expire. Basically I need an automatic check of expiration date of certificates. My requirements were

daily checks; notification by email; check for certificates on internal and external network; check for certificates on non-web service (imap, pop, …).

There are a couple of tools that cover part of my requirements butRead more.

Graphing Terena CRL stats

The OpenSSL heartbleed vulnerability CVE-2014-0160 has been all over the news this month. I posted an overview on what to do and how to detect exploit attempts.

Generating new certificates is one of the advices to cope with this vulnerability. A new certificate means that you have to revoke the old one. Revoked certificates are ‘announced’ in a CRL, or a certificate revocation list.

SANS ISC has a graph on certificates revokedRead more.

Ulogd-viz, visualize iptables / netfilter / ufw logs

I have iptables on a couple of different Linux hosts. There are a number of tools that allow you to centralize the logs of different hosts (and services) but they often focus on some form of alert management. I need something that allows me to gather the logs from different hosts, put them all in one central database and then generate some statistics on this data.

Iptables logs to the local syslogger but ulogd allowsRead more.

Heartbleed, the OpenSSL vulnerability. What Should I Do?

    Jump to Update 10-Apr-2014

    Jump to Update 11-Apr-2014

    Jump to Update 12-Apr-2014

    Jump to Update 24-Apr-2014

Unless you’ve been hiding under a rock you must have heard about the OpenSSL heartbleed vulnerability CVE-2014-0160.

Software using or linked against OpenSSL 1.0.1 through 1.0.1f (inclusive) is vulnerable. This post focuses on what you have to do and how you can detect it. This post is not on what the vulnerability is about.

It is importantRead more.

Install ModSecurity on Ubuntu (from source)

ModSecurity is an embeddable web application firewall or WAF. It can be installed as part of your existing web server infrastructure.

ModSecurity is available as a package for different Linux distributions but these versions are often outdated. I installed ModSecurity from source on Ubuntu 12.0.4 LTS.

Start by downloading the source tarball from the ModSecurity website. The full code is available via GitHub and the links to the tarballs are available from the home page.

Read more.

RFC1918 replies from public DNS servers

I was reading on DNS rebinding and how browsers protect us with DNS pinning.

I was curious how public DNS servers reply when you do a query for a host that is binded to an RFC1918 address.

DNS rebinding basically works as follows.

Attackers control the DNS of a domain (‘www.example.com’); A user is lured (phishing, web commment, …) into visiting a site controlled by the attacker, the DNS response is a public IPRead more.