Archives For Saltzer and Schroeder principles

20140122-072236.jpg

A clank of botnets

More bad news for the Internet this week as a plague of BotNets launched a successful wave of denial of service attacks on Dyn, a dynamic domain name service provider. The attacks on Dyn propagated through to services such as Twitter (OK no great loss), Github, The Verge, Playstation Network, Box and Wix. Continue Reading…

It is a common requirement to either load or update applications over the air after a distributed system has been deployed. For embedded systems that are mass market this is in fact a fundamental necessity. Of course once you do have an ability to load remotely there’s a back door that you have to be concerned about, and if the software is part of a vehicle’s control system or an insulin pump controller the consequences of leaving that door unsecured can be dire. To do this securely requires us to tackle the insecurities of the communications protocol head on.

One strategy is to insert a protocol ‘security layer’ between the stack and the application. The security layer then mediate between the application and the Stack to enforce the system’s overall security policy. For example the layer could confirm:

  • that the software update originated from an authenticated source,
  • that the update had not been modified,
  • that the update itself had been authorised, and
  • that the resources required by the downloaded software conform to any onboard safety or security policy.

There are also obvious economy of mechanism advantages when dealing with protocols like the TCP/IP monster. Who after all wants to mess around with the entirety of the TCP/IP stack, given that Richard Stevens took three volumes to define the damn thing? Similarly who wants to go through the entire process again when going from IP5 to IP6? 🙂

Cyber security (Image Source: IT-Lex, via Google Images)

Safety versus security

There is a certain school of thought that views safety and security as essentially synonymous, and therefore that the principles of safety engineering are directly applicable to that of security, and vice versa. You might caricature this belief as the management idea that all one needs to do to generate a security plan is to take an existing safety plan and replace ‘safety’ with ‘security’ or ‘hazard’ with ‘threat’. A caricature yes, but one that’s not that much removed from reality 🙂

Continue Reading…

iVote_Logo

The best defence of a secure system is openness

Ensuring the security of high consequence systems rests fundamentally upon the organisation that sustains that system. Thus organisational dysfunction can and does manifest itself as an inability to deal with security in an effective fashion. To that end the ‘shoot the messenger’ approach of the NSW Electoral Commission to reports of security flaws in the iVote electronic voting system does not bode well for that organisation’s ability to deal with such challenges. Continue Reading…

More speed bumps on the road to the Internet of Everything

Continue Reading…

iOS-7 (Image source: Apple)

What iOS 7’s SSL/TLS security patch release tells us

While the commentators, pundits and software guru’s pontificate over Apple’s SSL/TLS goto fail bug’s root cause, the bug does provide an interesting perspective on Least Common Mechanism one of the least understood of Saltzer and Schroede’rs security principles. For those interested in the detail of what actually went wrong with ‘SSLProcessServerKeyExchange()’ click over to the Sophos post on the subject.

Continue Reading…

Linguistic security, and the second great crisis of computing

The components that make up distributed systems fundamentally need to talk to each other order to achieve coordinated behaviour. This introduces the need for components to have a common set of expectation of behaviour, including recognising the difference between valid and invalid messages. And fairly obviously this has safety and security implications. Enter the study of linguistic security to address the vulnerabilities introduced by the to date unrecognised expressive power of the languages we communicate with.

Continue Reading…