Toward Sensitive Information Redaction

Computer Science / www.isec.utulsa.edu

Toward Sensitive Information Redaction in a Collaborative,

Multilevel Security Environment

Peter Gehres, Nathan Singleton, George Louthan, John Hale

WikiSym 2010, Gdansk, Poland, July 8, 2010


Overview •  Background •  Related Work •  Motivation •  SecureWiki •  Challenges •  Potential Environments •  Acknowledgments



Background •  Multilevel Security (MLS)

–  Traditional military security model –  Each object is described by

•  Sensitivity level (unclassified, confidential, secret, top secret) •  Compartments (e.g nuclear, europe, missle defense)

•  Bell-La Padula –  Based on the MLS model –  Read Down –  Write Up


Background, cont. •  Text Redaction

–  Tradtional redaction •  Black out using a marker •  Cut out using scissors

–  Digital techniques •  Remove the underlying data •  Challenges:

–  Metadata –  Incomplete redaction

An example of traditional redaction


Related Work •  Intellipedia

–  Based on MediaWiki –  Three distinct wikis for unclassified, confidential and secret on

separate physical networks –  Problem: Many places to go for information on a single subject


Related Work •  Tearline Wiki

–  Aggregates multiple wikis with "tear lines" between the classifications

–  Problems •  Information is still segregated •  Still in testing at the NSA •  Proprietary technology

From Galois Brief, “Tearline Wiki: Information collaboration across security domains”


Motivations

•  To promote information sharing in sensitive environments –  Government –  Healthcare –  Corporate Intellectual Property

•  To combine all information about a subject into a single, consolidated view by increasing granularity


SecureWiki - Architecture •  Store all article markup in separate data store

•  Generate keys to indicate redacted text in markup

•  Store keys in key store and generate tokens used to replace markup in page (mapped to a key by the key store)

•  Replace tokens with markup during render of page (after checking authentication)


SecureWiki

Architecture Diagram


SecureWiki - Example

Excerpt from http://en.wikipedia.org/wiki/KFC


Initial Page Request

SECRET


Initial Page Request

SECRET


The “Unclassified” Recipe


Wiki Markup

[snip]

In 1983, writer [[William Poundstone]] examined the recipe in his book ''[[Big Secrets]]''. He

reviewed Sanders' [[patent]] application, and advertised in college newspapers for present or

former employees willing to share their knowledge. From the former he deduced that Sanders had

diverged from other common fried-chicken recipes by varying the amount of oil used with the

amount of chicken being cooked, and starting the cooking at a higher temperature (about

{{convert|400|F|-1}}) for the first minute or so and then lowering it to {{convert|250|F|-1}} for the

remainder of the cooking time. {\redact 123} Following his buyout in 1964, Colonel Sanders

himself expressed anger at such changes, saying:

[snip]



SECRET



SECRET



SECRET

abc


The “Confidential” Recipe


Wiki Markup [snip]

{\redact 456}

On February 9, 2009, the secret recipe returned to KFC's Louisville headquarters in a more secure, computerized

vault.

In 1983, writer [[William Poundstone]] examined the recipe in his book ''[[Big Secrets]]''. He reviewed

Sanders' [[patent]] application, and advertised in college newspapers for present or former employees willing to

share their knowledge. From the former he deduced that Sanders had diverged from other common fried-chicken

recipes by varying the amount of oil used with the amount of chicken being cooked, and starting the cooking at a

higher temperature (about {{convert|400|F|-1}}) for the first minute or so and then lowering it to {{convert|250|F|-1}}

for the remainder of the cooking time. Several of Poundstone's contacts also provided samples of the seasoning

mix, and a food lab found that it consisted solely of [[sugar]], [[flour]], [[salt]], [[black pepper]] and [[monosodium

glutamate]] (MSG). He concluded that it was entirely possible that, in the years since Sanders sold the chain, later

owners had begun skimping on the recipe to save costs

[snip]



SECRET



SECRET



SECRET

def


Wiki Markup [snip]

Before the move, KFC disclosed the following details about the recipe and its security arrangements:

* The recipe, which includes exact amounts of each component, is written in pencil on a single sheet of notebook

paper and signed by Sanders.

* The recipe was locked in a filing cabinet with two separate combination locks. The cabinet also included vials of

each of the {\redact 789} herbs and spices used.

* Only two executives had access to the recipe at any one time. KFC refuses to disclose the names and titles of

either executive

* One of the two executives said that no one had come close to guessing the contents of the secret recipe, and

added that the actual recipe would include some surprises.

On February 9, 2009, the secret recipe returned to KFC's Louisville headquarters in a more secure, computerized

vault.

[snip]

[snip]



SECRET



SECRET



SECRET


Final Output – “Secret” Recipe


Challenges •  Metadata

–  A page’s existence may be classified –  Data inference

•  Verification of security controls –  Certification and accreditation

•  Declassifying Information –  Bell-La Padula prohibits write-down

•  Implementation –  Hooks into parser –  Saving data –  Revision History?


Potential Environments •  Military and government

•  Medical research –  Collaboration in blind/double-blind studies –  Compliance with HIPPA PII/PHI requirements

•  Corporations –  Chinese Wall implementation –  Inter-departmental segregation –  Inter-corporation collaboration


Conclusions •  Redaction in wikis is possible with high granularity for

secure environments.

•  SecureWiki integrates the information into a single view based on the user's access level.

•  SecureWiki has potential not only in government but also corporate, healthcare and other environments.


Future Work •  Develop a proof of concept

–  Determine the real challenges in implementation –  Expand the workflow of the system

•  Determine the wiki framework (MediaWiki?) –  Ability to add our framework without modifying (too much)

core code –  Access controls –  Known vulnerabilities


Acknowledgements •  Mr. Philippe Beaudette, Head of Reader Relations,

Wikimedia Foundation

•  Dr. Rose Gamble, Professor, The University of Tulsa

•  This material is based on research sponsored by DARPA under agreement number FA8750-09-1-0208. The U.S. Government is authorized to reproduce and distribute reprints for Governmental purposes notwithstanding any copyright notation thereon. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of DARPA or the U.S. Government.


Questions?

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Toward Sensitive Information Redaction