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Category Archives for "Security"

Debunking Trump’s “secret server”

According to this Slate article, Trump has a secret server for communicating with Russia. Even Hillary has piled onto this story.

This is nonsense. The evidence available on the Internet is that Trump neither (directly) controls the domain "trump-email.com", nor has access to the server. Instead, the domain was setup and controlled by Cendyn, a company that does marketing/promotions for hotels, including many of Trump's hotels. Cendyn outsources the email portions of its campaigns to a company called Listrak, which actually owns/operates the physical server in a data center in Philidelphia.


In other words,  Trump's response is (minus the political bits) likely true, supported by the evidence. It's the conclusion I came to even before seeing the response.

When you view this "secret" server in context, surrounded by the other email servers operated by Listrak on behalf of Cendyn, it becomes more obvious what's going on. In the same Internet address range of Trump's servers you see a bunch of similar servers, many named [client]-email.com. In other words, trump-email. Continue reading

GRE over IPSec Tunnel and NAT Between Cisco and VyOS

The goal of this tutorial is to provide a configuration for Cisco and VyOS network devices with configured PAT (Port Address Translation) that connect two remote sides A and B through point-to-point GRE tunnel encapsulated into a IPsec tunnel. In a previous tutorial we proved that GRE tunnels in conjunction with IPsec tunnels transmit multicast traffic while data integrity, authentication and confidentiality was in place. I also provided a simple configuration of GRE, IPsec tunnel and OSPF routing protocol on the Cisco and VyOS routers. In this tutorial I will go further and provide full configuration of  the all network devices including PAT and access-lists.  picture1_network_infrastructure

Picture 1 - Network Topology

Topology Description - Side A

Each side has a Layer 2 Cisco switch located in a LAN network. A switch connects hosts to its switchports. Each switchport is assigned to a particular VLAN. For instance, a host PC1 is connected to the switch SW1 and the switchport is assigned to a VLAN 100. Hosts in VLAN 100 (subnet 192.168.1.0/24) have guaranteed access to a remote subnet 192.168.2.0/24 via GRE/IPsec tunnel. A NAT access-list configured on a router R1 ensures that IP address of the host in VLAN 100 is not translated by PAT when a destination address is Continue reading

Configuring Raspberry Pi as a router

I'm setting up a little test network for IoT devices, one isolated a bit from my home network. This is a perfect job for a computer like the Raspberry Pi (or similar computers, such as the Odroid-C2, which is what I'm actually using here). I thought I'd blog the setup details in case anybody else wanted to setup their own isolated home network.

Choice of hardware

The Raspberry Pi B v3 is a fine choice, but there are many alternatives. I'm using the Odroid C2 instead. It's nearly the same, but the chief difference for my purposes is that the Ethernet adapter is native. On the RPi, the Ethernet adapter is actually connected via USB. Network utilities don't like USB Ethernet as much.

The choice of hardware dictates the operating system. Download the latest version of Ubuntu for the Odroid C2. They keep moving around where to get it, but you can google "odroid c2 downloads" to find it. My version is Ubuntu MATE 16.04 LTS.


Your home network

Your home network likely uses the addresses 192.168.1.xxx. This is also the range that most of the devices I'm testing will use as their initial defaults. Therefore, Continue reading

Reaction: DevOps and Security

Over at TechBeacon, my friend Chris Romeo has an article up about DevOps and security. It’s interesting to me because this is actually an area I’d never thought about before, even though it makes sense. Given DevOps is essentially writing software to control infrastructure (like routers, compute, and storage), and software needs to be written in a way that is secure, then it should be obvious that DevOps software should be developed with good security principles gleaned from software development as part of the foundation.

And here we face a challenge, as Chris says—

There is no standard that defines security for DevOps, and the chances of a standard ever developing is small because different organizations are doing things their own way, and can’t even agree on a standard name. And while there is a standard for the secure development lifecycle (ISO/IEC 27034-1), few organizations are ever validated against it.

The key point in here is that every organization is doing things their own way. This isn’t wrong, of course, because every organization must have some “snowflakiness” to justify its existence, and that “snowflakiness” is often likely to show up, in a large way, in something like handling resources within Continue reading

Lamers: the problem with bounties

In my last two posts, I pointed out that the anti-spam technique known as "DKIM" cryptographically verifies emails. This can be used to verify that some of the newsworthy emails are, indeed, correct and haven't been doctored. I offer a 1 btc (one bitcoin, around ~$600 at current exchange rates) bounty if anybody can challenge this assertion.

Unfortunately, bounties attract lamers who think they deserve the bounty. 


This guy insists he wins the bounty because he can add spaces to the email, and add fields like "Cc:" that DKIM doesn't check. Since DKIM ignores extra spaces and only checks important fields, these changes pass. The guy claims it's "doctored" because technically, he has changed things, even though he hasn't actually changed any of the important things (From, Date, Subject, and body content).

No. This doesn't qualify for the bounty. It doesn't call into question whether the Wikileaks emails say what they appear to say. It's so obvious that people have already contacted me and passed on it, Continue reading

Politifact: Yes we can fact check Kaine’s email

This Politifact post muddles over whether the Wikileaks leaked emails have been doctored, specifically the one about Tim Kaine being picked a year ago. The post is wrong -- we can verify this email and most of the rest.

In order to bloc spam, emails nowadays contain a form of digital signatures that verify their authenticity. This is automatic, it happens on most modern email systems, without users being aware of it.

This means we can indeed validate most of the Wikileaks leaked DNC/Clinton/Podesta emails. There are many ways to do this, but the easiest is to install the popular Thunderbird email app along with the DKIM Verifier addon. Then go to the Wikileaks site and download the raw source of the email https://wikileaks.org/podesta-emails/emailid/2986.

As you see in the screenshot below, the DKIM signature verifies as true.


If somebody doctored the email, such as changing the date, then the signature would not verify. I try this in the email below, changing the date from 2015 to 2016. This causes the signature to fail.


There are some reasons DKIM might fail, specifically if the sender uses short keys. This doesn't apply to GMail, which uses strong 2048 bit keys, Continue reading

Yes, we can validate the Wikileaks emails

Recently, WikiLeaks has released emails from Democrats. Many have repeatedly claimed that some of these emails are fake or have been modified, that there's no way to validate each and every one of them as being true. Actually, there is, using a mechanism called DKIM.

DKIM is a system designed to stop spam. It works by verifying the sender of the email. Moreover, as a side effect, it verifies that the email has not been altered.

Hillary's team uses "hillaryclinton.com", which as DKIM enabled. Thus, we can verify whether some of these emails are true.

Recently, in response to a leaked email suggesting Donna Brazile gave Hillary's team early access to debate questions, she defended herself by suggesting the email had been "doctored" or "falsified". That's not true. We can use DKIM to verify it.

You can see the email in question at the WikiLeaks site: https://wikileaks.org/podesta-emails/emailid/5205. The title suggests they have early access to debate questions, and includes one specifically on the death penalty, with the text:
since 1973, 156 people have been on death row and later set free. Since 1976, 1,414 people have been executed in the U.S

Some notes on today’s DNS DDoS

Some notes on today's DNS outages due to DDoS.

We lack details. As a techy, I want to know the composition of the traffic. Is it blindly overflowing incoming links with junk traffic? Or is it cleverly sending valid DNS requests, overloading the ability of servers to respond, and overflowing outgoing link (as responses are five times or more as big as requests). Such techy details and more make a big difference. Was Dyn the only target? Why were non-Dyn customers effected?

Nothing to do with the IANA handover. So this post blames Obama for handing control of DNS to the Russians, or some such. It's silly, and not a shred of truth to it. For the record, I'm (or was) a Republican and opposed handing over the IANA. But the handover was a symbolic transition of a minor clerical function to a body that isn't anything like the U.N. The handover has nothing to do with either Obama or today's DDoS. There's no reason to blame this on Obama, other than the general reason that he's to blame for everything bad that happened in the last 8 years.

It's not a practice attack. A Bruce Schneier post created Continue reading
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