Tag Archives: Privacy

The Scenario:

Let’s say you are at a coffee shop with public internet access, and you don’t want someone snooping on your traffic, so you VPN to your work. However, you also don’t want to tunnel personal stuff out of your work VPN (chat, facebook, youtube, your personal email maybe?), so the question becomes, how do you create 2 different firewalls – one that ONLY allows you to VPN and does not allow any other applications access, and one that then controls the traffic within the VPN channel so that you can utilize the connection for some apps but not others?

At this point, there are only 2 “methods” of running a Firewall on Android: having root and managing/accessing IPTables, or, the only alternative – creating a sub-VPN channel that you pipe the traffic over and filter (which does not require root). Unfortunately, the second type (without root) will not work for this, since we will need to utilize the VPN channel ourselves for our VPN, and to my knowledge, Android let’s you setup only 1 active VPN channel. So, you need 1.) a way to root and 2.) a good Firewall

Continue Reading →Firewall the Inside of your OpenVPN or L2TP/IPSec Tunnel on Android

I read an interesting article last night which highlited some problems with the way SSH process communication happens. I am writing a post about it because it is so simple and yet so effective.

Here is the scenario:
Let’s say that you have a linux system running the latest set of patches/OpenSSH. You have multiple users on the system, and one or more of them have sudo/su/escalated privileges. The idea is that when user ‘A’ connects to the system, user ‘C’ will be able to sniff out their password.

The details:
The idea is that almost all ssh daemons by default are configured to use “Privilege Separation”. This means that sshd spawns a process (child) that is unprivileged to listen for incoming network requests. After the user authenticates, another process gets created running as the authenticated user. The magic happens in between these two processes.

A simple example:
User ‘C’ ssh-es into the system, escalates their privledges (either by legitimate or non-legitimate means) and starts listening for newly created ssh ‘net’ processes. As soon as user ‘C’ sees a process being crated, they immediately attach strace to it.

A simple way to do it is by:

or even better:


Continue Reading →Sniffing SSH Password from the Server Side

This post is a bit different, but I think some people will find it very interesting. What got me to write this was an interesting article posted by Kevin Mitnick via his twitter account: http://news.cnet.com/8301-27080_3-20077732-245/kevin-mitnick-shows-how-easy-it-is-to-hack-a-phone/?part=rss&tag=feed&subj=News-Security. Kevin’s claim is that “Any 15-year-old that knows how to write a simple script can find a VoIP provider that spoofs caller ID and set this up in about 30 minutes”, and my only question is: what will you do with the other 25 minutes?

Spoofing your Caller ID is legal in the US only if done via VOIP services for legal and legitimate uses, or to block sending your caller ID, but again, only if it is used for legal purposes. An example of a legitimate use is spoofing your own home/cell phone number when making outbound calls via VOIP/SIP. Another example would be spoofing an outgoing number (a bit like NATing) when sitting at a private (let’s say for example 2,3,4, or 5 digit) extension. There are many scenarios where this is absolutely needed — like offices, enterprises, remote employees/road warriors, and phone support.
Spoofing your Caller ID is not legal for false identity, threatening/harassing someone, pranking, lying, or other such negative and immoral actions. If you are interested in some more information, you can find some here: http://www.gordostuff.com/2011/06/fcc-ups-caller-id-spoofing-penalties.html, and here: http://www.gordostuff.com/2011/02/is-faking-caller-id-legal-in-united.html. This said, I am providing this information for anyone who wants to learn about how this is done, or/and is interested in setting it up for their business or personal use, but ONLY for legal and legitimate uses. I am in no way responsible if you do something stupid or illegal. Here is a good background/history and more information on Caller ID Spoofing: http://www.calleridspoofing.info/

The assumption here is that you have some things already setup and working. The article is titled “Spoofing Caller ID on the fly from any phone” and not “how to spoof your Caller ID”. I am assuming that you have: a sip trunk provider with an outgoing plan, a DID, a SIP server with some advanced features (Asterisk and OpenPBX, or something like TrixBox), and most of all — a working setup. The first step is getting DISA (Direct Inward System Access – http://www.voip-info.org/wiki/view/Asterisk+cmd+DISA). The idea is that you will dial your DID phone number, and the sip trunk provider will route it to your IP address. From there, your server will handle the call and connect you inside your system. I absolutely suggest setting up a DISA password/passcode, otherwise, you leave yourself open to abuse and other people will be able to potentially make calls and use your sip account. It is also important to note that generally, you can simply set a from name and number right here in the DISA outbound options. But again, the idea is to make this dynamic. Ones you dial into your system, the next step is to setup an extension that will handle the rest of this. Leave your context “from-internal” if you want to be able to make external calls by default — necessary in order to bridge the active call to your destination. If you are using Asterisk or TrixBox, go to /etc/asterisk/extensions_custom.conf, and enter something like this:

Now here’s what’s happening: When you get your DID, you get the DISA context. From there, after you authenticate yourself with a pin and now you are in your system. At this point, you would hook in your custom context, in this case called “proof-of-concept-custom”. Make sure that the word “custom” is present somewhere. At this point, your recipe will be executed. The first thing you want to do is answer. You can look up each of these commands at the voip-info.org website. For example, Answer: http://www.voip-info.org/wiki/view/Asterisk+cmd+Answer. The next step is to wait 2 seconds. Then you will speak out the current caller ID. This is really just so you know where you are coming from – it is not neccessary. The play (mp3/wav/etc…) play is not really necessary either, but it can be used to queue up different actions. If you will play something, the suggestion is to Answer the channel before hand, and pause/wait for a bit. The next step is to read 10 digits into the “digito” variable. For good measure, and to prevent a mistake, you can speak out the digits again, and then set them as the current Caller ID (the spoofing part). At this point, you can play another sound to queue up the next action. As an extra precaution/security-by-obscurity step, you can prompt for another pin. In this case, it’s “98765”. After the pin has been successfully entered, you can signal via a sound, and then dial and bridge the call to the same number that you set as your Caller ID (impractical, but just for the purpose of a proof of concept). You can very easily modify this to ask for a destination number and call that destination number instead. Please note that this will charge you a twice from the point that you dial the call and bridge it — once for the current/already active call, and once for the new call that you are making to your destination.

Again, there are many legitimate and absolutely necessary cases for this. If you work in any company, most of the time they will not disclose private numbers. If the company is very large, they might simply not have/want to buy individual “routable” phone numbers. Your desk extension of “1234” can be masked behind a general number which routes to “directory/support” when called back. Another great case is someone who works from remote. Say that you work from home and are part of a support group. A customer calls you and reports a problem. Now you want to call the customer back, but you don’t want him to have your personal home number/cellphone – you can spoof your support number and call the customer back.

Something interesting to note is that VOIP/SIP system can choose to not respect Caller ID (cid) blocking/spoofing, and and 1-800/other TOLL-FREE numbers simply do not respect it.

The only point of this article is to demonstrate how easy it is to achieve this dynamically. Again, this is something that you can very easily set statically in the extension or DISA settings. This is not something new or mind blowing. You could have done this over 10 years ago. The point is that you can have a setup which can be activated from any phone and within 30 seconds or less, you can have a dynamically spoofed Caller ID number.

For anyone who has not been following what is going on with WikiLeaks, here is a good place to start:



WikiLeaks is a “whistle blowing” website. A quick search about it brings you to:

Wikileaks was a website that published anonymous submissions and leaks of sensitive governmental, corporate, organizational, or religious documents, while attempting to preserve the anonymity and untraceability of its contributors.

This week WikiLeaks released some sensitive US documents:

The classified diplomatic cables released by online whistleblower WikiLeaks and reported on by news organizations in the United States and Europe provided often unflattering assessments of foreign leaders, including those of Germany and Italy.

The cables also contained revelations about long-simmering nuclear trouble spots, detailing U.S., Israeli and Arab fears of Iran’s growing nuclear program; U.S. concerns about Pakistan’s atomic arsenal; and U.S. discussions about a united Korean peninsula as a long-term solution to North Korean aggression.

There are also U.S. memos encouraging U.S. diplomats at the United Nations to collect detailed data about the UN secretary-general, his team and foreign diplomats ― going beyond what is considered the normal run of information-gathering expected in diplomatic circles.

None of the revelations is particularly explosive, but their publication could prove problematic for the officials concerned.

The short version of what happened is that WikiLeaks was the target of many DDoS attacks. Eventually, the website was shut down. They decided to change their hosting provider and use Amazon’s AWS (Public Cloud Service). After a few days, Amazon shut down their website claiming that it violated their terms of service. They brought the site in another location, and then their DNS provider decided to shut them down.

The reality is that WikiLeaks is exercising their right of freedom of speech. The problem is that they have some very sensitive information, and this makes political high profile figures nervous. However, when you move past the details of what happened, you come to the realization and real concern — Public Cloud Censorship.

This is the perfect example of why companies are afraid of using Public Clouds (outsourcing your infrastructure to someone else). As you can see from this example, your entire business can be shut down in a matter of minutes, just because someone has a different opinion than yours. This brings massive concern and rightfully so. I really think that the long term solution is private clouds. Take this great technology and deploy it within your own datacenter. When you look at this from the top, it looks a lot like web hosting — you can either outsource your web hosting to a company like DreamHost and BlueHost, or you can do it yourself. There are benefits to both, but at the end, it comes down to your concern for privacy and freedom.

Along with many other people, I personally think that Amazon had the chance to do something great, and as the Guardian and EFF pointed out: “Instead, Amazon ran away with its tail between its legs.”

I have a Twitter Dilema, and I am very curious what people think. Here’s the problem:

If you make your tweets private (which is what I have done right now), you are not forcefully followed by spammers, BUT when you add friends, if they don’t add you back, they will not see your replies.

If you make your tweets public, you are force to deal with the 13 year olds which are trying to get 50,000 followers and 2 million tweets.

I personally think that this is a bug with twitter. If you have protected tweets, and think that someone is ‘safe enough’ to follow, twitter should automatically allow that individual to see your tweets, even though they are protected. This only makes sense. Heck, enable an option to toggle this.

What does everyone else think?