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The evolution to modern phased array architectures

October 20, 2015
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Journal Article
Author:
Jeffrey S. Herd
…
Published in:
Proceedings of the IEEE, Vol. 104, No. 3, March 2016, pp. 519-529.
Topic:
radar
R&D area:
R&D group:

Summary

Phased array technology has been evolving steadily with advances in solid-state microwave integrated circuits, analysis and design tools, and reliable fabrication practices. With significant government investments, the technologies have matured to a point where phased arrays are widely used in military systems. Next-generation phased arrays will employ high levels of digitization, which enables a wide range of improvements in capability and performance. Digital arrays leverage the rapid commercial evolution of digital processor technology. The cost of phased arrays can be minimized by utilizing high-volume commercial microwave manufacturing and packaging techniques. Dramatic cost reductions are achieved by employing a tile array architecture, which greatly reduces the number of printed circuit boards and connectors in the array.
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Summary

Phased array technology has been evolving steadily with advances in solid-state microwave integrated circuits, analysis and design tools, and reliable fabrication practices. With significant government investments, the technologies have matured to a point where phased arrays are widely used in military systems. Next-generation phased arrays will employ high levels of...

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The evolution to modern phased array architectures

Mission assurance as a function of scale

October 14, 2015
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Conference Paper
Author:
Pierre C. Trepagnier
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Published in:
36th NATO Information Systems Technology Panel, 14-16 October 2015.
Topic:
systems analysis
R&D area:
R&D group:

Summary

Since all Department of Defense (DoD) missions depend on cyber assets and capabilities, a dynamic and accurate cyber dependency analysis is a critical component of mission assurance. Mission analysis aims to identify hosts and applications that are "mission critical" so they can be monitored, and resources preferentially allocated to mitigate risks. For missions limited in duration and scale (tactical missions), dependency analysis is possible to conceptualize in principle, although currently difficult to realize in practice. However, for missions of long duration and large scale (strategic missions), the situation is murkier. In particular, cyber researchers struggle to find technologies that will scale up to large numbers of hosts and applications, since a typical strategic DoD mission might expect to leverage a large enterprise network. In this position paper, we argue that the difficulty is fundamental: as the mission timescale becomes longer and longer, and the number of hosts associated with the mission becomes larger and larger, the mission encompasses the entire network, and mission defense becomes indistinguishable from classic network defense. Concepts generally associated with mission assurance, such as fight-through, are not well suited to these long timescales and large networks. This train of thought leads us to reconsider the concept of "scalability" as it applies to mission assurance, and suggest that a hierarchical abstraction approach be applied. Large-scale, long duration mission assurance may be treated as the interaction of many small-scale, short duration tactical missions.
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Summary

Since all Department of Defense (DoD) missions depend on cyber assets and capabilities, a dynamic and accurate cyber dependency analysis is a critical component of mission assurance. Mission analysis aims to identify hosts and applications that are "mission critical" so they can be monitored, and resources preferentially allocated to mitigate...

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Mission assurance as a function of scale

Control jujutsu: on the weaknesses of fine-grained control flow integrity

October 12, 2015
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Conference Paper
Author:
Hamed Okhravi
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Published in:
22nd ACM Conf. on Computer and Communications Security, 12-16 October 2015.
Topic:
systems analysis
R&D area:
R&D group:

Summary

Control flow integrity (CFI) has been proposed as an approach to defend against control-hijacking memory corruption attacks. CFI works by assigning tags to indirect branch targets statically and checking them at runtime. Coarse-grained enforcements of CFI that use a small number of tags to improve the performance overhead have been shown to be ineffective. As a result, a number of recent efforts have focused on fine-grained enforcement of CFI as it was originally proposed. In this work, we show that even a finegrained form of CFI with unlimited number of tags and a shadow stack (to check calls and returns) is ineffective in protecting against malicious attacks. We show that many popular code bases such as Apache and Nginx use coding practices that create flexibility in their intended control flow graph (CFG) even when a strong static analyzer is used to construct the CFG. These flexibilities allow an attacker to gain control of the execution while strictly adhering to a fine-grained CFI. We then construct two proof-of-concept exploits that attack an unlimited tag CFI system with a shadow stack. We also evaluate the difficulties of generating a precise CFG using scalable static analysis for real-world applications. Finally, we perform an analysis on a number of popular applications that highlights the availability of such attacks.
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Summary

Control flow integrity (CFI) has been proposed as an approach to defend against control-hijacking memory corruption attacks. CFI works by assigning tags to indirect branch targets statically and checking them at runtime. Coarse-grained enforcements of CFI that use a small number of tags to improve the performance overhead have been...

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Control jujutsu: on the weaknesses of fine-grained control flow integrity

Timely rerandomization for mitigating memory disclosures

October 12, 2015
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Conference Paper
Author:
David Bigelow
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Published in:
22nd ACM Conf. on Computer and Communications Security, 12-16 October 2015.
Topic:
systems architecture
R&D area:
R&D group:

Summary

Address Space Layout Randomization (ASLR) can increase the cost of exploiting memory corruption vulnerabilities. One major weakness of ASLR is that it assumes the secrecy of memory addresses and is thus ineffective in the face of memory disclosure vulnerabilities. Even fine-grained variants of ASLR are shown to be ineffective against memory disclosures. In this paper we present an approach that synchronizes randomization with potential runtime disclosure. By applying rerandomization to the memory layout of a process every time it generates an output, our approach renders disclosures stale by the time they can be used by attackers to hijack control flow. We have developed a fully functioning prototype for x86_64 C programs by extending the Linux kernel, GCC, and the libc dynamic linker. The prototype operates on C source code and recompiles programs with a set of augmented information required to track pointer locations and support runtime rerandomization. Using this augmented information we dynamically relocate code segments and update code pointer values during runtime. Our evaluation on the SPEC CPU2006 benchmark, along with other applications, show that our technique incurs a very low performance overhead (2.1% on average).
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Summary

Address Space Layout Randomization (ASLR) can increase the cost of exploiting memory corruption vulnerabilities. One major weakness of ASLR is that it assumes the secrecy of memory addresses and is thus ineffective in the face of memory disclosure vulnerabilities. Even fine-grained variants of ASLR are shown to be ineffective against...

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Timely rerandomization for mitigating memory disclosures

Enhancing the far-ultraviolet sensitivity of silicon complementary metal oxide semiconductor imaging arrays

October 1, 2015
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Journal Article
Author:
Kurt D. Retherford
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Published in:
J. Astron. Telesc. Instrum. Syst., Vol. 1, No. 4, Oct. - Dec. 2015, 046001.
Topic:
semiconductor (CMOS)
R&D area:
R&D group:

Summary

We report our progress toward optimizing backside-illuminated silicon P-type intrinsic N-type complementary metal oxide semiconductor devices developed by Teledyne Imaging Sensors (TIS) for far-ultraviolet (UV) planetary science applications. This project was motivated by initial measurements at Southwest Research Institute of the far-UV responsivity of backside-illuminated silicon PIN photodiode test structures, which revealed a promising QE in the 100 to 200 nm range. Our effort to advance the capabilities of thinned silicon wafers capitalizes on recent innovations in molecular beam epitaxy (MBE) doping processes. Key achievements to date include the following: (1) representative silicon test wafers were fabricated by TIS, and set up for MBE processing at MIT Lincoln Laboratory; (2) preliminary far-UV detector QE simulation runs were completed to aid MBE layer design; (3) detector fabrication was completed through the pre-MBE step; and (4) initial testing of the MBE doping process was performed on monitoring wafers, with detailed quality assessments.
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Summary

We report our progress toward optimizing backside-illuminated silicon P-type intrinsic N-type complementary metal oxide semiconductor devices developed by Teledyne Imaging Sensors (TIS) for far-ultraviolet (UV) planetary science applications. This project was motivated by initial measurements at Southwest Research Institute of the far-UV responsivity of backside-illuminated silicon PIN photodiode test structures...

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Enhancing the far-ultraviolet sensitivity of silicon complementary metal oxide semiconductor imaging arrays

Enhanced signal processing algorithms for the ASR-9 Weather Systems Processor

October 1, 2015
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Journal Article
Author:
John Y. Cho
Published in:
J. Atmos. Ocean. Technol., Vol. 32, No. 10, October 2015, pp. 1847-59.
Topic:
algorithms
R&D area:
R&D group:

Summary

New signal processing algorithms for the Airport Surveillance Radar-9 (ASR-9) Weather Systems Processor (WSP) are introduced. The Moving Clutter Spectral Processing for Uneven-Sampled Data with Dealiasing (MCSPUDD) algorithm suite removes isolated moving clutter targets and corrects aliased velocity values on a per-range-gate basis. The spectral differencing technique is applied to the low- and high-beam data to produce a dual-beam velocity estimate that is more accurate than the current autocorrelation-lag-1-based approach. Comparisons with Terminal Doppler Weather Radar (TDWR) data show that estimate errors are reduced by 8%, 15%, and 15% for the low-, high-, and dual-beam velocities, respectively.
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Summary

New signal processing algorithms for the Airport Surveillance Radar-9 (ASR-9) Weather Systems Processor (WSP) are introduced. The Moving Clutter Spectral Processing for Uneven-Sampled Data with Dealiasing (MCSPUDD) algorithm suite removes isolated moving clutter targets and corrects aliased velocity values on a per-range-gate basis. The spectral differencing technique is applied to...

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Enhanced signal processing algorithms for the ASR-9 Weather Systems Processor

Characterizing phishing threats with natural language processing

September 28, 2015
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Conference Paper
Author:
Michael C. Kotson
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Published in:
2015 IEEE Conf. on Communications and Network Security (CNS), 28-30 September 2015.
Topic:
systems analysis
R&D area:
R&D group:

Summary

Spear phishing is a widespread concern in the modern network security landscape, but there are few metrics that measure the extent to which reconnaissance is performed on phishing targets. Spear phishing emails closely match the expectations of the recipient, based on details of their experiences and interests, making them a popular propagation vector for harmful malware. In this work we use Natural Language Processing techniques to investigate a specific real-world phishing campaign and quantify attributes that indicate a targeted spear phishing attack. Our phishing campaign data sample comprises 596 emails - all containing a web bug and a Curriculum Vitae (CV) PDF attachment - sent to our institution by a foreign IP space. The campaign was found to exclusively target specific demographics within our institution. Performing a semantic similarity analysis between the senders' CV attachments and the recipients' LinkedIn profiles, we conclude with high statistical certainty (p < 10^-4) that the attachments contain targeted rather than randomly selected material. Latent Semantic Analysis further demonstrates that individuals who were a primary focus of the campaign received CVs that are highly topically clustered. These findings differentiate this campaign from one that leverages random spam.
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Summary

Spear phishing is a widespread concern in the modern network security landscape, but there are few metrics that measure the extent to which reconnaissance is performed on phishing targets. Spear phishing emails closely match the expectations of the recipient, based on details of their experiences and interests, making them a...

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Characterizing phishing threats with natural language processing

Very large graphs for information extraction (VLG) - detection and inference in the presence of uncertainty

September 21, 2015
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Project Report
Author:
Benjamin A. Miller
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Published in:
MIT Lincoln Laboratory Report VLG-2
Topic:
signal processing
R&D area:
R&D group:

Summary

In numerous application domains relevant to the Department of Defense and the Intelligence Community, data of interest take the form of entities and the relationships between them, and these data are commonly represented as graphs. Under the Very Large Graphs for Information Extraction effort--a one year proof-of-concept study--MIT LL developed novel techniques for anomalous subgraph detection, building on tools in the signal processing research literature. This report documents the technical results of this effort. Two datasets--a snapshot of Thompson Reuters' Web of Science database and a stream of web proxy logs--were parsed, and graphs were constructed from the raw data. From the phenomena in these datasets, several algorithms were developed to model the dynamic graph behavior, including a preferential attachment mechanism with memory, a streaming filter to model a graph as a weighted average of its past connections, and a generalized linear model for graphs where connection probabilities are determined by additional side information or metadata. A set of metrics was also constructed to facilitate comparison of techniques. The study culminated in a demonstration of the algorithms on the datasets of interest, in addition to simulated data. Performance in terms of detection, estimation, and computational burden was measured according to the metrics. Among the highlights of this demonstration were the detection of emerging coauthor clusters in the Web of Science data, detection of botnet activity in the web proxy data after 15 minutes (which took 10 days to detect using state-of-the-practice techniques), and demonstration of the core algorithm on a simulated 1-billion-vertex graph using a commodity computing cluster.
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Summary

In numerous application domains relevant to the Department of Defense and the Intelligence Community, data of interest take the form of entities and the relationships between them, and these data are commonly represented as graphs. Under the Very Large Graphs for Information Extraction effort--a one year proof-of-concept study--MIT LL developed...

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Very large graphs for information extraction (VLG) - detection and inference in the presence of uncertainty

Cyber network mission dependencies

September 18, 2015
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Technical Report
Author:
Alexia Schulz
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Published in:
MIT Lincoln Laboratory Report TR-1189
Topic:
systems analysis
R&D area:
R&D group:

Summary

Cyber assets are critical to mission success in every arena of the Department of Defense. Because all DoD missions depend on cyber infrastructure, failure to secure network assets and assure the capabilities they enable will pose a fundamental risk to any defense mission. The impact of a cyber attack is not well understood by warfighters or leadership. It is critical that the DoD develop better cognizance of Cyber Network Mission Dependencies (CNMD). This report identifies the major drivers for mapping missions to network assets, introduces existing technologies in the mission-mapping landscape, and proposes directions for future development.
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Summary

Cyber assets are critical to mission success in every arena of the Department of Defense. Because all DoD missions depend on cyber infrastructure, failure to secure network assets and assure the capabilities they enable will pose a fundamental risk to any defense mission. The impact of a cyber attack is...

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Cyber network mission dependencies

The AFRL-MITLL WMT15 System: there's more than one way to decode it!

September 17, 2015
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Conference Paper
Author:
Jeremy Gwinnup
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Published in:
Proc. 10th Workshop on Statistical Machine Translation, 17-18 September 2015, pp. 112-9.
Topic:
machine translation
R&D area:
R&D group:

Summary

This paper describes the AFRL-MITLL statistical MT systems and the improvements that were developed during the WMT15 evaluation campaign. As part of these efforts we experimented with a number of extensions to the standard phrase-based model that improve performance on the Russian to English translation task creating three submission systems with different decoding strategies. Out of vocabulary words were addressed with named entity postprocessing.
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Summary

This paper describes the AFRL-MITLL statistical MT systems and the improvements that were developed during the WMT15 evaluation campaign. As part of these efforts we experimented with a number of extensions to the standard phrase-based model that improve performance on the Russian to English translation task creating three submission systems...

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The AFRL-MITLL WMT15 System: there's more than one way to decode it!
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