Insinuator


Some outright rants from a bunch of infosec practitioners.

Archive for August 2010

This is currently the most frequent search term leading Internet users to the Troopers website.
Probably Sheran Gunasekera’s great presentation “Bugs & Kisses – Spying on BlackBerry users for fun” is the piece they are after. Whatever they look for, this search term may help to shed light to an aspect that seems a bit overlooked in the ongoing debate about governments (U.A.E., Saudi Arabia, India) trying to get their hands on communication acts performed with BlackBerries in their countries.
[For those interested in that discussion this blog entry of Bruce Schneier may serve as a starting point.]

Given that most readers of this blog using a BlackBerry will most likely do so with a BlackBerry Enterprise Server (BES) installation, in this post I’ll focus on those deployments and will subsequently not cover BlackBerry Internet Service (BIS) scenarios.

RIM, very understandably, stresses the fact that in the current BES architecture – presumably – they [RIM] can only process (thus “see”) the data stream encrypted (by symmetric ciphers regarded sufficiently secure) between the BES servers usually placed on corporate soil and the endpoint devices (the Blackberries themselves).

What they don’t mention is the simple fact that cryptographic techniques quite often only secure some data’s transport path, but not elements on the endpoints (where the data is unencrypted and further processed). What if either the (BlackBerry) devices provide means to eavesdrop on the traffic –  and Sheran discussed the relevant APIs in his talk, referring to the “Etisalat case” where in 2009 the major U.A.E. telecommunications provider distributed a software application for Blackberries that essentially allowed somebody [who?] to eavesdrop on emails by sending a copy of each email to a certain server – or even the BES itself is “somehow interfered with”? This article from Indiatimes at least suggests the latter possibility for BES servers located in India. Here’s a quoted excerpt:
“Significantly, the only time an enterprise email sent from a BlackBerry device remains in an un-encrypted or ‘readable’ format is when it resides in the enterprise server. ‘Feeding the email from the enterprise server to the ISP’s monitoring systems can, accordingly, help security agencies access the communication in pure text form’, DoT [India’s Department of Telecommunications] proposal said.”

So, in short, just discussing if BlackBerry based communication can be intercepted in transit may be a bit short-sighted. Thinking about the devices and the code they run (and who’s allowed to install applications, by what means/from which sources, yadda yadda yadda) or considering “some countries’ regulatory requirements” when deploying BES servers might be helpful, too.

It should be noted that we do not allege RIM any dishonest motives whatsoever (actually we have a quite positive stance as for the overall security posture of their products, if nothing else see for example this newsletter analysing the over-the-air generation of master encryption keys between the BES and the devices).
We just want to raise some awareness to the mentioned “blind spots” in the current debate.

Have a great day,

Enno

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For those of you who missed it: Microsoft released the associated advisory yesterday, together with a hotfix introducing a new registry key that allows users to control the DLL search path algorithm. For a detailed explanation of the problem we refer to the excellent article on Ars Technica.

For the record: no, AV (anti-virus software) will – in most cases – not protect you from security problems related to this one. And, no, there is no easy patch for this one either.

Carefully reading the “Mitigating Factors” and “Workarounds” section in the MS advisory or this entry from our blog might provide ideas how to address this or similar stuff (in the future).

Wishing you all some sunny summer days,

Enno

Update: this article gives some more technical details and this one describes some real attack paths against popular applications. Sorry, guys, good luck with fighting this one with traditional AV…

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Just wanted to let you know that we sent out ERNW Newsletter 32 end of last week. As we promised it includes the results of  research regarding the question “Is browser virtualization a valid security control in order to mitigate browser based security risks?”.

Simon did a great job with writing the latest newsletter. It’s a 30-page document which should help you to have a basis for well-informed decisions when it comes to the deployment of an application virtualization technology.

Download a signed version of the PDF here, or visit the archive to browse other issues of our highly technical newsletters.

Best wishes,
Florian

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Aug/10

11

Try Loki!

Loki is set free!

Everybody who is interested in our newest tool ‘Loki’ is welcomed to head over to ERNW’s tool section and download it. Take this monster for a spin and let us know in the comments how you like it. Loki’s coding father Daniel is more than happy to answer your questions and criticism.

You don’t even know what Loki is?

In short: An advanced security testing tool for layer 3 protocols.

In long: Have a read in the Blackhat2010 presentation slides and mark TROOPERS11 in your calendar to meet the guys behind the research and for sure get a live demo of the capabilities – development is still ongoing, so prepare yourself for even more supported protocols and attack types.

And again: Talking about TROOPERS11… we’ve already selected the first round of speakers. Details to be published soon :)

Have a great day!
Florian

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One of the biggest pains in the ass of most ISOs – and subsequently subject of fierce debates between business and infosec – is the topic of “Browser Security”, i.e. essentially the question “How to protect the organization from malicious code  brought into the environment by users surfing the Internet?”.

Commonly the chain of events (of a typical malware infection act) can be broken down to the following steps:

1.) Some code – no matter if binary or script code – gets transferred (mostly: downloaded) to some system “from the Internet”, that means “over the network”.

2.) This code is executed by some local piece of software (where “execution” might just mean “parse a PDF” ;-).
[btw, if you missed it: after Black Hat Adobe announced an out-of-band patch scheduled for 08/16, so stay tuned for another Adobe Reader patch cycle next week…]

3.) This code causes harm (either on it’s own, either by reloaded payloads) to the local system, to the network the system resides in or to other networks.

Discussing potential security controls can be centered around these steps, so we have

a) The area of network based controls, that means all sorts of “malicious content protection” devices like proxies filtering (mainly HTTP and FTP) traffic based on signatures, URL blacklists etc., and/or network based intrusion prevention systems (IPSs).
Practically all organizations use some of this stuff (however quite a number of them – unfortunately – merely banks on these pieces). Let me state this clearly: overall using network based (filtering) controls contributes significantly to “overall protection from browser based threats” and we won’t discuss the advantages/disadvantages of this approach right here+now.
Still it should be noted that this is what we call a “detective/reactive control”, as it relies on somehow detecting the threat and scrubbing it after the detection act).

b) Controls in the “limit the capability to execute potentially harmful code” space. Which can be broken down to things like
– minimizing the attack surface (e.g. by not running Flash, iTunes etc. at all). The regular readers of this blog certainly knows our stance as for this approach ;-).
– configuration tweaks to limit the script execution capabilities of some components involved, like all the stuff to be found in IE’s zone model and associated configuration options (see this document for a detailed discussion of this approach).
– patching (the OS, the browser, the “multimedia extensions” like Flash and Quicktime, the PDF reader etc.) to prevent some “programmatic abuse” of the respective components.

Again, we won’t dive into an exhaustive discussion of the advantages/disadvantages of this approach right here+now.

c) Procedures or technologies striving to limit the harm in case an exploit happens “in browser space” (which, as of our definition, encompasses all add-ons like Flash, Quicktime etc.). This includes DEP, IE protected mode, sandboxing browsers etc.

Given the weaknesses the network based control approach might have (in particular in times of targeted attacks. oops, sorry, of course I mean: in times of the Advanced Persistent Threat [TM] ;-)) and the inability (or reluctance?) to tackle the problem on the “code execution” front-line in some environments, in the interim another potential control has gained momentum in “progressive infosec circles”: using virtualization technologies to isolate the browser from the (“core”) OS, other applications or just the filesystem.
Three main variants come to mind here: full OS virtualization techniques (represented, for example, by Oracle VirtualBox or VMware Workstation), application virtualization solutions (like Microsoft App-V or VMware ThinApp) and, thirdly, what I call “hosted browsing” (where some MS Terminal Server farm potentially located in a DMZ, or even “the cloud” may serve as “[browser] hosting infrastructure”).
In general, on an architecture level this is a simple application of the principle of “isolation” – and I really promise to discuss that set of architectural security principles we use at ERNW at some point in this blog ;-).

While I know that some of you, dear readers, use virtualization technologies to “browse safely” on a daily (but individual use) basis, there’s still some obstacles for large scale use of this approach, like how to store/transfer or print documents, how to integrate client certificates – in particular when on smart cards – into these scenarios, how to handle “aspects of persistence” (keeping cookies, bookmarks vs. not keeping potentially infected “browser session state”) etc.
And, even if all these problems can be solved, the big question would be: does it help, security-wise? Or, in infosec terms: to what degree is the risk landscape changed if such an approach would be used to tackle the “Browser Security Problem”?

To contribute to this discussion we’ve performed some tests with an application virtualization solution (VMware ThinApp) recently. The goal of the tests was to determine if exploits can be stopped from causing harm if they happened within a virtualized deployment, which modes of deployment to use, which additional tweaks to apply etc.
The results can be found in our next newsletter to be published at the end of this week. This post’s purpose was to provide some structure as for “securing the browser” approaches. and to remind you that – in the end of the day – each potential security control must be evaluated from two main angles: “What’s the associated business impact and operational effort?” and “How much does it mitigate risk[s]?”.
Have a great day,
Enno

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