Phishing in the Clouds

Again on Phishing, this time with a new twist.

We all know and by now use complex SaaS Cloud services, like Microsoft’s Office 365, Google’s G Suite, Amazon services and so on. They are all very modular, meaning that there are multiple data storage services and multiple application services from which to choose and use. Often a user must authorise a Cloud App to access her/his own data, and the App can be also by an external provider (a “partner” of the service). The Authorisation is usually implemented with OAuth which, in a few words, is a secure delegation access protocol based on the exchange of cryptographic keys.

So what is the scam? Simple: you receive an email which looks like coming from [name your Cloud provider here] and asks you to authorise an App (which looks authentic) to access your data. You do not need to insert any password since you are already logged-in your Cloud service platform, but just to click on the button, and that’s it!

You have given access to all your Cloud data and services to a fraudster, who can get your data and act as you!

For more details read for example this article by ArsTechnica.

Cloud, Network Security and SASE

We know very well that years ago we lost the concept of (security) network perimeter. Still too often we approach network security with the underlying idea of perimeter defenses: inside the permiter all is ok, and the “firewall” protects us from the outside world.

But in the current world of increasing Cloud / Software as a Service (SaaS) services and Software Defined Networking (SDN), it becomes increasingly impossible to manage IT security from the center of the traditional network and to deploy the protections on the edges. We need to manage the security of traditional and legacy applications, cloud applications, internal and mobile users, all at the same time and with a single approach.

From the networking security point of view this should require to look at our network as a (software defined) mesh of connections composed underneath by different backbones, trunks, local networks and VPNs. Security, access and privileges should be identity-driven and globally distributed on the network. This should imply that the preferred architecture to implement and govern such a security network should be cloud-based if not cloud-native.

If I understand correctly, this is, at least in part, the idea of the most recent approach to Network Security proposed by Gartner and called “Secure Access Service Edge – SASE” (see here and here for more infos).

Is it truly impossible to separate VMs running on the same HW?

More and more results appear, like this last one, on weaknesses and vulnerabilities of Virtual Machines running on usual (commodity) hardware. The most troublesome results are not due to software vulnerabilities, but rely only on the hardware architecture which supports it. If cryptographic private keys can be stolen and covert channels can be established evading the current isolation mechanisms provided by hardware and virtualization software (see also my previous posts on Clouds), how much can we trust at least the IaaS Cloud Services?

Cloud Security and HW Security Features

Security is hard, we know quite well by now, but instead of getting easier it seems that, as time goes by, it is getting harder.

Consider Public Cloud: in a Public Cloud environment, the threat scenario is much more complex than in a dedicated, on-premises HW one. Assuming that in both cases the initial HW and SW configuration is secure, the threat scenario for services running on dedicated, on-premises HW consists of external attacks either directly from the network or mediated by the system users who could (unintentionally) download malware into the service. Instead the threat scenario in a Public Cloud environment must also include attacks from other services running on the same HW (other virtual machines, tenants, dockers etc.) and attacks from the infrastructure itself running the services (hypervisors on host machines).

Protecting virtual machines and cloud services from other machines and services running on the same HW and from the hypervisor is hard. New hardware features are needed to be able to effectively separate the guest services from each other and from the host. But even hardware features are not easy to design and implement to these purposes.

For example, Intel has introduced the SGX hardware extensions to create enclaves to manage in HW very sensitive data like cryptographic keys. In this paper it has been shown, as initially feared by Rutkowska, that these HW extensions both provide security features to the users but also to the attackers, who can exploit them to create practically invisible and undetectable malware. In the article it is actually shown in a particular scenario, how it is possible to recover some secret RSA keys used for digital signatures sealed in one enclave from another enclave. Since not even the hypervisor can see what there is in one enclave, the malware is practically undetectable.

IT security is a delicate balance between many factors, HW, SW, functionalities, human behaviour etc. and the more complex is this ecosystem, the easier it is to find loopholes in it and ways to abuse it.

Hardware Vulnerabilities (Again), Cloud and Mobile Security

Have a very Happy New Year!

… and to start 2017 on a great note, I write again about Hardware Vulnerabilities with comments on Cloud and Mobile Security.

The opportunity for this blog entry has been provided to me by the talk “What could possibly go wrong with <insert x86 instruction here>? Side effects include side-channel attacks and bypassing kernel ASLR” by Clémentine Maurice and Moritz Lipp at Chaos Computer Club 2016 which I suggest to watch (it lasts 50 minutes and it is not really technical despite its title).

A super-short summary of the talk is that it is possible to mount very effective side- (in particular time-) channel attacks on practically any modern Operating System which allow to extrafiliate data, open communication channel and spy on activities like keyboards inputs. All of this using only lecit commands and OS facilities, but in some innovative ways.

The reason for which these attacks are possibile is that the hardware does not prevent them, actually some hardware features, added to improve performances, make these attacks easier or even possible (see also my previous post on Hardware Vulnerabilities about this). So from the Security point of view these Hardware features should be considered as Vulnerabilities.

What is it possible to do with these techniques? Considering Cloud, it is possible to monitor the activities of another Virtual Machine running on the same hardware, extract secrect cryptography keys (but this depends on how the algorithm and protocols are implemented), establish hidden communication channels etc.

Similarly for Mobile, it is possible to have a totally lecit App to monitor the keyboard activity, or 2 Apps to establish a hidden communication so that one reads some data and the other sends it to a remote destination, all without violating any security rule (actually each one having very limited privilegies and restricted setups).

Morevoer it seeems easy to embed this kind of attacks in lecit applications and current anti-virus seem to lack the capabilities needed to intercept them. Indeed the activites performed to implement these attacks look almost identical to the ones performed by any program and it seems that only a particular performance monitoring could discover them.


Homomorphic encryption and trusting the Clouds

Homomorphic encryption is an old idea but only in 2009 and the work of Gentry started to have some possible practical applications. Since then there have been quite impressive improvements in the research in this field of cryptography, also due to the need to improve the security of data managed by Cloud systems.

In brief, homomorphic algorithms are cryptographic algorithms that allow to do computations, like sums, multiplications, searches etc., on encrypted data giving encrypted results, without knowing the encryption key.

It should be obvious that these algorithms would be very useful for Clouds’ applications since the owner of the data would be able to use the data remotely by keeping at the same time the data, and the result of the computations, always encrypted in the Cloud application.

Unfortunately homomorphic encryption is not ready yet for general use, but it has just appeared an interesting research paper by Microsoft Reasearch announcing the release of a SEAL (Simple Encryption Arithmetic Library), a library for using homomorphic encryption in bioinformatics, genomic and other research areas.

News of the week

Some news of this week that caught my eye:

  • A claim for a new “indestructible” rootkit: BadBIOS: true or advertisement? See here.
  • Lavabit and Silent Circle join forces in the Dark Mail Alliance to create a really secure end-to-end email service. See here.
  • Amazon will build a 600M USD cloud for the CIA, IBM is not too happy about that… See here.
  • Bitcoin “crisis” and the advent of Litecoin, what is it going on in the world of online currencies? See here for a report and here for the latest news.