<![CDATA[[SecurityRatty] tag: usenix]]> http://securityratty.com/tag/usenix Wed, 10 Oct 2007 18:48:17 +0000 iRatty Engine http://blogs.law.harvard.edu/tech/rss <![CDATA[TrueCrypt's Deniable File System]]> http://securityratty.com/article/723a30942bcc2bbbe6f365b4d74045e7 http://securityratty.com/article/723a30942bcc2bbbe6f365b4d74045e7 new paper that breaks the deniable encryption feature of TrueCrypt version 5.1a. Basically, modern operating systems leak information like mad, making deniability a very difficult requirement to satisfy.
ABSTRACT: We examine the security requirements for creating a Deniable File System (DFS), and the efficacy with which the TrueCrypt disk-encryption software meets those requirements. We find that the Windows Vista operating system itself, Microsoft Word, and Google Desktop all compromise the deniability of a TrueCrypt DFS. While staged in the context of TrueCrypt, our research highlights several fundamental challenges to the creation and use of any DFS: even when the file system may be deniable in the pure, mathematical sense, we find that the environment surrounding that file system can undermine its deniability, as well as its contents. Finally, we suggest approaches for overcoming these challenges on modern operating systems like Windows.
The students did most of the actual work. I helped with the basic ideas, and contributed the threat model. Deniability is a very hard feature to achieve.
There are several threat models against which a DFS could potentially be secure:
  • One-Time Access. The attacker has a single snapshot of the disk image. An example would be when the secret police seize Alice’s computer.
  • Intermittent Access. The attacker has several snapshots of the disk image, taken at different times. An example would be border guards who make a copy of Alice’s hard drive every time she enters or leaves the country.
  • Regular Access. The attacker has many snapshots of the disk image, taken in short intervals. An example would be if the secret police break into Alice’s apartment every day when she is away, and make a copy of the disk each time.
Since we wrote our paper, TrueCrypt released version 6.0 of its software, which claims to have addressed many of the issues we've uncovered. In the paper, we said:
We analyzed the most current version of TrueCrypt available at the writing of the paper, version 5.1a. We shared a draft of our paper with the TrueCrypt development team in May 2008. TrueCrypt version 6.0 was released in July 2008. We have not analyzed version 6.0, but observe that TrueCrypt v6.0 does take new steps to improve TrueCrypt’s deniability properties (e.g., via the creation of deniable operating systems, which we also recommend in Section 5). We suggest that the breadth of our results for TrueCrypt v5.1a highlight the challenges to creating deniable file systems. Given these potential challenges, we encourage the users not to blindly trust the deniability of such systems. Rather, we encourage further research evaluating the deniability of such systems, as well as research on new yet light-weight methods for improving deniability.
So we cannot break the deniability feature in TrueCrypt 6.0. But, honestly, I wouldn't trust it. There have been two news articles (and a SlashDot thread) about the paper. One talks about a generalization to encrypted partitions. If you don't encrypt the entire drive, there is the possibility -- and it seems very probable -- that information about the encrypted partition will leak onto the unencrypted rest of the drive. Whole disk encryption is the smartest option. Our paper will be presented at the 3rd USENIX Workshop on Hot Topics in Security (HotSec '08). I've written about deniability before.
]]> Fri, 18 Jul 2008 02:56:02 +0000 truecrypt deniable file system file system truecrypt version system truecrypt dfs deniable truecrypt disk-encryption software systems TrueCrypt's Deniable File System <![CDATA[Show 028 - An Interview with Bill Cheswick]]> http://securityratty.com/article/e2b76fcc8fd5ae0b6ef0cc50f2744a36 http://securityratty.com/article/e2b76fcc8fd5ae0b6ef0cc50f2744a36 Bill Cheswick

On the 28th episode of The Silver Bullet Security Podcast, Gary interviews Bill Cheswick, a lead member of technical staff at AT&T Research and all around security guru. Bill has been working in computer security for over 35 years. He coined the term “proxy” in 1990 with reference to firewalls, and co-authored the book Firewalls and Internet Security which was used to train an entire generation of sys admins. Gary and Bill discuss whether we’re winning or losing the computer security war, how security threats have evolved from pimply-faced teenagers to organized crime, whether we should move security into “the cloud,” and whether re-naming “Christmas lights” to “solstice lights” would bypass NJ holiday decoration ordinances.

]]> Tue, 15 Jul 2008 15:30:25 +0000 bill bill cheswick computer security computer security war solstice lights att research holiday decoration ordinances apache web server term proxy Show 028 - An Interview with Bill Cheswick <![CDATA[MetriCon 3.0]]> http://securityratty.com/article/6fc4e1e7c6a2bcb752da2cfcc280a220 http://securityratty.com/article/6fc4e1e7c6a2bcb752da2cfcc280a220 Along with OWASP's AppSec conferences, MetriCon is at the top of my list of conferences. MetriCon brings together people with varied background and a common interest in making security more objective and measurable. This year's conference chair is Dan Geer and the agenda and speakers looks like the best yet. MetriCon 3.0 is July 29 in San Jose, along with the Usenix Security conference.

]]> Thu, 03 Jul 2008 11:56:32 +0000 metricon metricon brings security usenix security conference appsec conferences conferences san jose conference chair dan geer MetriCon 3.0 <![CDATA[Upcoming Talks and Training]]> http://securityratty.com/article/d68ebfdb5917f37e9c36ff618bc2fbcb http://securityratty.com/article/d68ebfdb5917f37e9c36ff618bc2fbcb Here is my current list of talks and training


  • "Breaking Web Services," Monday July 7: OWASP Twin Cities  - "SOA and Web services promise wonderful interoperability, but distributed systems create lots of room for fantastic failures. This session will explore the gory details of unique vulnerabilities at each layer of the SOA stack - from the WSDL interfaces to XML processing (XSD, XPath and XQuery), to the implementation languages liike Java and C#, to new security standards like WS-Security and SAML.

    I gave a version of  this talk with Brian Chess at the 2008 RSA Conference.

  •  "Web Services and SSO: There and Back Again" at Ping's SSO Summit. July 25, Keystone, CO - "What happens to your identity information and business data after you press "SUBMIT" on a website? These bits have a journey as dangerous as Frodo Baggins' travels through Mordor. This talk traces the path from the website through the perils that lurk in the enterprise and legacy systems. We will explore what threats are encountered along the way, and how to design a cost effective security architecture with Security Token Servers using open standards."   
  •  "SOA, web services, and XML Security" 1 day training at Usenix Security July 29. This is a public 1 day version of my training see the link for details
]]> Thu, 03 Jul 2008 10:32:26 +0000 security usenix security july ws-security xml security july web services day version security standards soa Upcoming Talks and Training <![CDATA[An improved clock-skew measurement technique for revealing hidden services]]> http://securityratty.com/article/cf8c25995dfd225667b93b60ff885c6a http://securityratty.com/article/cf8c25995dfd225667b93b60ff885c6a In 2006 I published a paper on remotely estimating a computer’s temperature, based on clock skew. I showed that by inducing load on a Tor hidden service, an attacker could cause measurable changes in clock skew and so allow the computer hosting the service to be re-identified. However, it takes a very long time (hours to days) to obtain a sufficiently accurate clock-skew estimate, even taking a sample every few seconds. If measurements are less granular than the 1 kHz TCP timestamp clock source I used, then it would take longer still.

This limits the attack since in many cases TCP timestamps may be unavailable. In particular, Tor hidden services operate at the TCP layer, stripping all TCP and IP headers. If an attacker wants to estimate clock skew over the hidden service channel, the only directly available clock source may be the 1 Hz HTTP timestamp. The quantization noise in this case is three orders of magnitude above the TCP timestamp case, making the approach I used in the paper effectively infeasible.

While visiting Cambridge in summer 2007, Sebastian Zander developed an improved clock skew measurement technique which would dramatically reduce the noise of clock-skew measurements from low-frequency clocks. The basic idea, shown below, is to only request timestamps very close to a clock transition, where the quantization noise is lowest. This requires the attacker to firstly lock-on to the phase of the clock, then keep tracking it even when measurements are distorted by network jitter.

Synchronized vs random sampling

Sebastian and I wrote a paper — An Improved Clock-skew Measurement Technique for Revealing Hidden Services — describing this technique, and showing results from testing it on a Tor hidden service installed on PlanetLab. The measurements show a large improvement over the original paper, with two orders of magnitude lower noise for low-frequency clocks (like the HTTP case). This approach will allow previous attacks to be executed faster, and make previously infeasible attacks possible.

The paper will be presented at the USENIX Security Symposium, San Jose, CA, US, 28 July – 1 August 2008.

]]> Thu, 26 Jun 2008 01:12:21 +0000 clock-skew measurement technique clock clock-skew clock transition clock source clock skew magnitude lower noise tcp tcp timestamps An improved clock-skew measurement technique for revealing hidden services <![CDATA[OMG, This is Sooo "Kid in A Candy Store" :-)]]> http://securityratty.com/article/9b3bac7b19792be59d269c8a75c73330 http://securityratty.com/article/9b3bac7b19792be59d269c8a75c73330 First USENIX Workshop on the Analysis of System Logs (WASL '08)
December 7, 2008
San Diego, CA, USA"

CFP here.
About me: http://www.chuvakin.org
]]> Thu, 08 May 2008 10:21:00 +0000 usenix workshop system logs san diego org usa wasl analysis cfp december OMG, This is Sooo "Kid in A Candy Store" :-) <![CDATA[Designing Processors to Support Hacking]]> http://securityratty.com/article/004b7b28860368244b04893395cb7923 http://securityratty.com/article/004b7b28860368244b04893395cb7923 This won best-paper award at the First USENIX Workshop on Large-Scale Exploits and Emergent Threats: "Designing and implementing malicious hardware," by Samuel T. King, Joseph Tucek, Anthony Cozzie, Chris Grier, Weihang Jiang, and Yuanyuan Zhou.

Hidden malicious circuits provide an attacker with a stealthy attack vector. As they occupy a layer below the entire software stack, malicious circuits can bypass traditional defensive techniques. Yet current work on trojan circuits considers only simple attacks against the hardware itself, and straightforward defenses. More complex designs that attack the software are unexplored, as are the countermeasures an attacker may take to bypass proposed defenses.

We present the design and implementation of Illinois Malicious Processors (IMPs). There is a substantial design space in malicious circuitry; we show that an attacker, rather than designing one speci?c attack, can instead design hardware to support attacks. Such ?exible hardware allows powerful, general purpose attacks, while remaining surprisingly low in the amount of additional hardware. We show two such hardware designs, and implement them in a real system. Further, we show three powerful attacks using this hardware, including a login backdoor that gives an attacker complete and highlevel access to the machine. This login attack requires only 1341 additional gates: gates that can be used for other attacks as well. Malicious processors are more practical, more flexible, and harder to detect than an initial analysis would suggest.

Theoretical? Sure. But combine this with stories of counterfeit computer hardware from China, and you've got yourself a potentially serious problem.

]]> Thu, 24 Apr 2008 09:52:33 +0000 additional additional hardware hardware exible hardware design hardware design counterfeit computer hardware attacks support attacks Designing Processors to Support Hacking <![CDATA[Blue Box #69: Linksys SPA-941 vulnerability, SIP DDoS, New release of SIPVicious, Asterisk security roadmap, other VoIP security news, listener commen]]> http://securityratty.com/article/27c750855cc69253762c55b647a5e9a8 http://securityratty.com/article/27c750855cc69253762c55b647a5e9a8

Synopsis:Blue Box #69: Linksys SPA-941 vulnerability, SIP DDoS, New release of SIPVicious, Asterisk security roadmap, other VoIP security news, listener comments and more

Welcome to Blue Box: The VoIP Security Podcast #69, a 46-minute podcast  from Dan York and Jonathan Zar covering VoIP security news, comments and opinions.   

Download the show here (MP3, 21MB) or subscribe to the RSS feed to download the show automatically. 

You may also listen to this podcast right now:

Show Content:

Show Content:

Comments, suggestions and feedback are welcome either as replies to this post  or via e-mail to blueboxpodcast@gmail.com.  Audio comments sent as attached MP3 files are definitely welcome and will be played in future shows.  You may also call the listener comment line at either +1-206-350-7280 or via SIP to 'bluebox@voipuser.org' to leave a comment there. 

Thank you for listening and please do let us know what you think of the show.

]]> Sat, 27 Oct 2007 10:33:08 +0000 listener comment line comment line comments listener comments asterisk security roadmap voip security news comment asterisk linksys spa Blue Box #69: Linksys SPA-941 vulnerability, SIP DDoS, New release of SIPVicious, Asterisk security roadmap, other VoIP security news, listener commen <![CDATA[Show 019 - An Interview with Mikko Hyppönen]]> http://securityratty.com/article/8d4c1ac50d91bb2578e47e4ff74686d5 http://securityratty.com/article/8d4c1ac50d91bb2578e47e4ff74686d5 Mikko Hyppönen

For the 19th episode of The Silver Bullet Security Podcast, Gary interviews Mikko Hyppönen, Chief Research Officer at F-Secure. During this show, Gary and Mikko discuss Helsinki and Finnish pronunciation, whether mobile viruses are all hype or a legitimate threat, if the iPhone as a closed system is good or bad for security, and Mikko’s prediction for the appearance of the first mobile botnet. They also chat about Finnish hip-hop.

]]> Thu, 18 Oct 2007 11:21:38 +0000 mikko mikko discuss helsinki gary interviews mikko gary chief research officer finnish hip-hop finnish pronunciation f-secure 19th episode Show 019 - An Interview with Mikko Hyppönen <![CDATA[Blue Box #69: Linksys SPA-941 vulnerability, SIP DDoS, New release of SIPVicious, Asterisk security roadmap, other VoIP security news, listener commen]]> http://securityratty.com/article/7b5b101e127e6ca8bf4e918498c6e398 http://securityratty.com/article/7b5b101e127e6ca8bf4e918498c6e398

Synopsis:Blue Box #69: Linksys SPA-941 vulnerability, SIP DDoS, New release of SIPVicious, Asterisk security roadmap, other VoIP security news, listener comments and more

Welcome to Blue Box: The VoIP Security Podcast #69, a 46-minute podcast  from Dan York and Jonathan Zar covering VoIP security news, comments and opinions.   

Download the show here (MP3, 21MB) or subscribe to the RSS feed to download the show automatically. 

You may also listen to this podcast right now:

Show Content:

Show Content:

Comments, suggestions and feedback are welcome either as replies to this post  or via e-mail to blueboxpodcast@gmail.com.  Audio comments sent as attached MP3 files are definitely welcome and will be played in future shows.  You may also call the listener comment line at either +1-206-350-7280 or via SIP to 'bluebox@voipuser.org' to leave a comment there. 

Thank you for listening and please do let us know what you think of the show.

]]> Wed, 10 Oct 2007 18:48:17 +0000 listener comment line comment line comments listener comments asterisk security roadmap voip security news comment asterisk linksys spa Blue Box #69: Linksys SPA-941 vulnerability, SIP DDoS, New release of SIPVicious, Asterisk security roadmap, other VoIP security news, listener commen