How to Hack an Election

Now that the election is behind us, the discussion has turned to potential involvement by foreign governments and whether they had their hand in altering the course of US democracy by tampering with the integrity of our election systems. The CIA has all but admitted that there was definite Russian interference aimed at tilting our election. Continue reading “How to Hack an Election”

How to Spot a Fake Facebook Account

Ever get a friend request from someone you don’t know and have never met before? More often than not, these accounts are created by criminals looking to harvest your personal information, or scam you in some other fashion.

It typically starts when you receive a friend request from someone you don’t know. And you have no mutual friends in common:


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Carrier Grade NAT and the DoS Consequences

Republished from Corero DDoS Blog:

The Internet has a very long history of utilizing mechanisms that may breathe new life into older technologies, stretching it out so that newer technologies may be delayed or obviated altogether. IPv4 addressing, and the well known depletion associated with it, is one such area that has seen a plethora of mechanisms employed in order to give it more shelf life.

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Is DDoS Mitigation as-a-Service Becoming a Defacto Offering for Providers?

Republished from Corero DDoS Blog:

It’s well known in the industry that DDoS attacks are becoming more frequent and increasingly debilitating, turning DDoS mitigation into a mission critical initiative. From the largest of carriers to small and mid-level enterprises, more and more Internet connected businesses are becoming a target of DDoS attacks. What was once a problem that only a select few dealt with is now becoming a regularly occurring burden faced by network operators.

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Black Hat OSPF Vulnerabilities: Much Ado About Nothing

Imagine a group of researchers planning to speak at a conference regarding a previously undiscovered vulnerability present in most homes that would allow a thief to rob your home of its valuables with complete ease.  You would probably be interested in hearing what they had to say so you could take the necessary precautions to protect your home.

Now imagine when they presented their findings, they went on to state that it was incredibly easy to do, so long as you left your front door open and also provided them with the security code for any alarm systems.  You would probably find this implausible and simply the proliferation of fear, uncertainty, and doubt.

That’s precisely what happened last week at the well-respected Black Hat security conference in Las Vegas when researchers from the Israel Institute of Technology and Advanced Defense Systems, Ltd. presented their findings of a serious vulnerability present in OSPF.  So serious in fact, the researchers stated the only way to properly mitigate the threat, short of fixing the protocol, is to switch to another routing protocol such as RIP or IS-IS.

The researchers went on to present their research of two previously undiscovered methods of poisoning routing information within an OSPF domain such that bogus information could be propagated and used for a multitude of malicious purposes.

The first attack allows for the creation of a remote false adjacency, whereby an unsuspecting victim router goes on to form an adjacency with a phantom router.  Once this adjacency is formed, the attacker can then flood the victim router with bogus Link-State Advertisements (LSAs).

The second attack allows the flooding of what are known as Disguised LSAs, whereby a victim router would accept spoofed LSAs which it believed were generated by another router within the OSPF domain.

While both of these previously unknown attack vectors might raise some eyebrows and create cause for concern, the researchers made some pretty big assumptions regarding the ability to perform such an attack.  The assumptions were that in order to perform such an attack, one would first need to insert a router into the network, and once this was accomplished they would then somehow need to obtain the MD5 authentication key that is widely used to secure the communications channel between OSPF neighbors.

Without a doubt, there is some merit to what these researchers have found and to a protocol junkie like myself I am always interested to learn the inner-workings of these protocols.  However, what they’ve completely overlooked is the first tenet of information security which is to ensure the physical environment is properly secured.  In most environments, gaining physical access to the network might prove difficult enough.  Nonetheless, if an attacker were able to insert such a device, the net effect would be that such attacks would be short-lived as it would be fairly trivial for a network administrator to isolate the offending device and remove it from the network.

Furthermore, and perhaps the biggest barrier to entry, they’ve failed to recognize that the likelihood of someone obtaining the authentication key.  While MD5 is known to have some serious deficiencies and vulnerable to collision attacks, it still represents a pretty high bar for the would-be attacker.  And various vendors are already rolling out HMAC-SHA for the authentication function within OSPFv2.

In addition, the researchers admitted that in their testing of the first exploit, the victim router tore down the adjacency to the phantom router after 125 seconds because the victim router did not receive the proper acknowledgement packets from the phantom router.  Once again, the net effect is that if the attackers were able to meet the first two assumptions, their attack would still be relatively short-lived.

While OSPF is widely used throughout the Internet as a whole, you probably have better odds of winning the lottery than actually experiencing an attack such as these researchers have demonstrated.  The researchers presented some pretty bold claims, but at the end of the day didn’t really present anything that wasn’t already widely known about the vulnerabilities inherent within the OSPF protocol given the assumptions the researchers made.  Their assumptions are based on two barriers to entry, which doesn’t make it impossible, but nonetheless incredibly difficult and highly implausible.  In my experience, attackers tend to move onto far easier targets.

There are a lot of things to worry about when it comes to protecting your corporate assets, but in my humble opinion, this is not one of them.  So rather than ripping out OSPF as these researchers would have you believe, you might perhaps be better served by taking a second look at your environment and ensuring the physical premises are properly secured.

Juniper SRX Tips :: Altering Default-Deny Behavior

In our previous article, we looked at using apply-groups to alter all the security policies uniformly on an SRX device such that they would all have an implicit logging statement. And while this is fine for all existing policies, it doesn’t log traffic which doesn’t match any explicitly defined security policy.

The reason for this is due to the fact that in Junos, traffic which doesn’t match an explicitly defined security policy matches against the default-deny policy.  However, given the fact that the default-deny policy is implicitly defined, apply-group configurations are of little benefit as apply-groups can only be inherited by those elements which have been explicitly defined.

Often in these cases, administrators will simply choose to create their own deny policies with the desired options and place this deny policy as the last policy for traffic going from one zone to another. However, in instances where there are many zones, it might prove too cumbersome and time consuming to manually configure this to accommodate all zones.

Clearly it would be more beneficial to have something akin to the Global Zone in ScreenOS which can be used to match on all traffic which doesn’t match against any of the explicitly defined security policies.  However, at the time of this writing, Global Zone functionality doesn’t exist in Junos.

The good news is that we can use the power of apply-groups once again to our benefit, this time to create an explicitly defined deny policy which will be inherited at the tail-end of all security policies defined within our configuration. Note that this will encompass both Inter-zone as well as Intra-zone traffic.

For this example, let’s assume that we want to log everything that would normally hit the default-deny policy. Let’s start by taking a look at our baseline configuration:

Here you can see we have a policy allowing all traffic outbound from the Users-subnet in the Trust zone towards the Untrust zone, and another policy allowing inbound HTTP traffic from the Untrust zone towards the Web Server in the Trust zone.  Now, in order to change the default-deny behavior and add additional options, we will use an apply-group to inherit a new policy at the tail-end of all previously defined policies, as follows:

Finally, let’s apply our apply-group at the [security policies] stanza within our configuration:

Now that we’ve completed the configuration, let’s examine the results of the application of our apply-group by taking a look at our security policies, this time by displaying the inherited configuration:

Once again, with just a couple of lines of code we can streamline the configuration to a large extent, in this case creating an explicitly defined deny policy which logs all traffic that would otherwise be silently discarded.  And best of all, we can do so without having to resort to manual configuration of each and every one.

In small installations this technique might be of little benefit, but in larger implementations consisting of dozens of zones with a combination of Interzone and Intrazone and bidirectional security policies, the benefit of such an approach cannot be understated.  Not only will this ease configuration burden, but it will ensure that all traffic which doesn’t match any of the existing security policies will be handled in a consistent manner.  Of course, as with previous examples, if there are certain policies that we don’t want to inherit this new default-deny, we can simply utilize the apply-group-except statement for each of those respective policies.

In our next article we will examine changing the built-in Junos application defaults so that we can customize timers and other parameters.

Juniper SRX Tips :: Uniform Security Policy Modification

Often there are instances where we want to affect all security policies configured on an SRX device.  For example, let’s say that we have thousands of policies configured on our firewall, and we want to enable logging for every single policy.  Obviously this would take some time if we were to do this manually on each and every individual policy, so an easier way is desired.

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