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Visualizing working sets

Evangelos P. Markatos
1997 ACM SIGOPS Operating Systems Review  
The regularity of access patterns can also be used in disk block placement policies so that nearby-accessed pages be placed in nearby p h ysical disk blocks.  ... 
doi:10.1145/271019.271021 fatcat:h45tehwlo5hrnlqxtqjvv2ydda

Privacy-Preserving Social Plugins

Georgios Portokalidis, Michalis Polychronakis, Angelos D. Keromytis, Evangelos P. Markatos
2012 USENIX Security Symposium  
The widespread adoption of social plugins, such as Facebook's Like and Google's +1 buttons, has raised concerns about their implications to user privacy, as they enable social networking services to track a growing part of their members' browsing activity. Existing mitigations in the form of browser extensions can prevent social plugins from tracking user visits, but inevitably disable any kind of content personalization, ruining the user experience. In this paper we propose a novel design for
more » ... rivacypreserving social plugins that decouples the retrieval of user-specific content from the loading of a social plugin. In contrast to existing solutions, this design preserves the functionality of existing social plugins by delivering the same personalized content, while it protects user privacy by avoiding the transmission of user-identifying information at load time. We have implemented our design in SafeButton, an add-on for Firefox that fully supports seven out of the nine social plugins currently provided by Facebook, including the Like button, and partially due to API restrictions the other two. As privacy-preserving social plugins maintain the functionality of existing social plugins, we envisage that they could be adopted by social networking services themselves for the benefit of their members. To that end, we also present a pure JavaScript design that can be offered transparently as a service without the need to install any browser add-ons.
dblp:conf/uss/PortokalidisPKM12 fatcat:zxmkkawrhffdfivvxc6iusc25m

Scap

Antonis Papadogiannakis, Michalis Polychronakis, Evangelos P. Markatos
2013 Proceedings of the 2013 conference on Internet measurement conference - IMC '13  
 Truncate streams to handle large traffic volume  Early discarding of uninteresting traffic  Assign priorities to streams  Overload control  Utilize multi-core systems for stream processing 10 markatos  ...  @ics.forth.gr -www.syssec-project.eu -HIPEAC-Athens 10/10/2014  Analyze the first N bytes of each stream  Cut the long tails if not interesting  Use Scap and set cutoff size per each stream 14 markatos  ... 
doi:10.1145/2504730.2504750 dblp:conf/imc/PapadogiannakisPM13 fatcat:hotfalye75h7rb7bt63blwcwp4

Tolerating Overload Attacks Against Packet Capturing Systems

Antonis Papadogiannakis, Michalis Polychronakis, Evangelos P. Markatos
2012 USENIX Annual Technical Conference  
The probability of not detecting an attack after N timeouts have expired is (1 − P (det)) N , and thus the probability of detecting the attack after N timeouts is 1 − (1 − P (det)) N : we see that the  ...  Also, the detection probability from Equation 2 implies that, on average, SPP will need T = 1/P (det) + 1 timeouts to detect the attack.  ... 
dblp:conf/usenix/PapadogiannakisPM12 fatcat:o74rzzop6fak7lw5dj3ynoiany

Generating realistic workloads for network intrusion detection systems

Spyros Antonatos, Kostas G. Anagnostakis, Evangelos P. Markatos
2004 Software engineering notes  
While the use of network intrusion detection systems (nIDS) is becoming pervasive, evaluating nIDS performance has been found to be challenging. The goal of this study is to determine how to generate realistic workloads for nIDS performance evaluation. We develop a workload model that appears to provide reasonably accurate estimates compared to real workloads. The model attempts to emulate a traffic mix of different applications, reflecting characteristics of each application and the way these
more » ... nteract with the system. We have implemented this model as part of a traffic generator that can be extended and tuned to reflect the needs of different scenarios. We also present an approach to measuring the capacity of a nIDS that does not require the setup of a full network testbed.
doi:10.1145/974044.974078 dblp:conf/wosp/AntonatosAM04 fatcat:ydilhdsldfamvkrixbazthrmku

Network–Level Polymorphic Shellcode Detection Using Emulation [chapter]

Michalis Polychronakis, Kostas G. Anagnostakis, Evangelos P. Markatos
2006 Lecture Notes in Computer Science  
Michalis Polychronakis and Evangelos P. Markatos are also with the University of Crete. We would like to thank the anonymous reviewers for their valuable feedback.  ... 
doi:10.1007/11790754_4 fatcat:ipvy732axzgglpbqgcozxt7ff4

Using reference counters in update based coherent memory [chapter]

Evangelos P. Markatos, Catherine E. Chronaki
1994 Lecture Notes in Computer Science  
Otherwise, p reads M remotely.  ...  When a page is replicated close to a processor p that accesses it, all future accesses to that page by p will be local, a fact that may result in performance improvement.  ... 
doi:10.1007/3-540-58184-7_162 fatcat:5dwyvebhgffp3i2rqp2trsevs4

MOR: Monitoring and Measurements through the Onion Router [chapter]

Demetris Antoniades, Evangelos P. Markatos, Constantine Dovrolis
2010 Lecture Notes in Computer Science  
A free and easy to use distributed monitoring and measurement platform would be valuable in several applications: monitoring network or server infrastructures, performing research experiments using many ISPs and test nodes, or checking for network neutrality violations performed by service providers. In this paper we present MOR, a technique for performing distributed measurement and monitoring tasks using the geographically diverse infrastructure of the Tor anonymizing network. Through several
more » ... case studies, we show the applicability and value of MOR in revealing the structure and function of large hosting infrastructures and detecting network neutrality violations. Our experiments show that about 7.5% of the tested organizations block at least one popular application port and about 5.5% of them modify HTTP headers. ISP 4. 1 . 3 . .
doi:10.1007/978-3-642-12334-4_14 fatcat:qikrjno7cjd3dnxcbml7blh6lu

Generating realistic workloads for network intrusion detection systems

Spyros Antonatos, Kostas G. Anagnostakis, Evangelos P. Markatos
2004 Software engineering notes  
While the use of network intrusion detection systems (nIDS) is becoming pervasive, evaluating nIDS performance has been found to be challenging. The goal of this study is to determine how to generate realistic workloads for nIDS performance evaluation. We develop a workload model that appears to provide reasonably accurate estimates compared to real workloads. The model attempts to emulate a traffic mix of different applications, reflecting characteristics of each application and the way these
more » ... nteract with the system. We have implemented this model as part of a traffic generator that can be extended and tuned to reflect the needs of different scenarios. We also present an approach to measuring the capacity of a nIDS that does not require the setup of a full network testbed.
doi:10.1145/974043.974078 fatcat:mcgv7fbgr5gj5dizlhefsrx6di

The Rise and Fall of Fake News sites: A Traffic Analysis [article]

Manolis Chalkiadakis, Alexandros Kornilakis, Panagiotis Papadopoulos, Evangelos P. Markatos, Nicolas Kourtellis
2021 arXiv   pre-print
Over the past decade, we have witnessed the rise of misinformation on the Internet, with online users constantly falling victims of fake news. A multitude of past studies have analyzed fake news diffusion mechanics and detection and mitigation techniques. However, there are still open questions about their operational behavior such as: How old are fake news websites? Do they typically stay online for long periods of time? Do such websites synchronize with each other their up and down time? Do
more » ... ey share similar content through time? Which third-parties support their operations? How much user traffic do they attract, in comparison to mainstream or real news websites? In this paper, we perform a first of its kind investigation to answer such questions regarding the online presence of fake news websites and characterize their behavior in comparison to real news websites. Based on our findings, we build a content-agnostic ML classifier for automatic detection of fake news websites (i.e. accuracy) that are not yet included in manually curated blacklists.
arXiv:2103.09258v1 fatcat:3gz4g45exralbora7usmnwwgby

Network-level polymorphic shellcode detection using emulation

Michalis Polychronakis, Kostas G. Anagnostakis, Evangelos P. Markatos
2006 Journal in Computer Virology  
Michalis Polychronakis and Evangelos P. Markatos are also with the University of Crete. We would like to thank the anonymous reviewers for their valuable feedback.  ... 
doi:10.1007/s11416-006-0031-z fatcat:jzacuavb7jdg7ftpjsjpwnnzsi

Dynamic Monitoring of Dark IP Address Space (Poster) [chapter]

Iasonas Polakis, Georgios Kontaxis, Sotiris Ioannidis, Evangelos P. Markatos
2011 Lecture Notes in Computer Science  
A number of security-related research topics are based on the monitoring of dark IP address space. Unfortunately there is large administrative overhead associated with the dynamic assignment of a specific subnet for monitoring purposes, such as the deployment of a honeypot farm or a distributed intrusion detection system. In this paper, we propose a system that enables the dynamic allocation of an unadvertised IP address subnet for use by a monitoring sensor. The system dynamically selects
more » ... rk subnets that have been allocated to the organization but are not being advertised, advertises them, and subsequently forwards all received traffic destined to the selected subnet to a monitoring sensor.
doi:10.1007/978-3-642-20305-3_20 fatcat:lderrc22ybccrdkvjvf2i3q55i

The remote enqueue operation on networks of workstations [chapter]

Evangelos P. Markatos, Manolis G. H. Katevenis, Penny Vatsolaki
1998 Lecture Notes in Computer Science  
Markatos, M Katevenis, and P.  ...  Although enqueueing noti cations in remote queues can be done completely in software, we p r o p o s e a h a r d w are remote enqueue operation that atomically enqueues a message noti cation in a remote  ... 
doi:10.1007/bfb0052203 fatcat:475a7zrstjadzc7j25m4x4lp5u

The Hitchhiker's Guide to Facebook Web Tracking with Invisible Pixels and Click IDs [article]

Paschalis Bekos, Panagiotis Papadopoulos, Evangelos P. Markatos, Nicolas Kourtellis
2022 arXiv   pre-print
Over the past years, advertisement companies have used a variety of tracking methods to persistently track users across the web. Such tracking methods usually include (first-party) cookies, third-party cookies, cookie synchronisation, as well as a variety of fingerprinting mechanisms. To complement these tracking approaches, Facebook recently introduced a new tracking method that attaches a one-time tag as a URL parameter (namely FBCLID) on outgoing links to other websites. Although one-time
more » ... s do not seem to have enough information to persistently track users, we demonstrate that this tag, despite its ephemeral nature, when combined with Facebook Pixel, can aid in persistent tracking of users across space (i.e., different websites) and time (i.e., both in the past as well as in the future). We show that this tag can be used to track web users' activity in the distant past -- even before those users had a Facebook account. In addition, by combining this tag with cookies that have rolling expiration dates, Facebook can also track users' browsing activities in the far future as well. Our experimental results suggest that more than 20% of the popular websites out there have adopted this technology, and thus can contribute to this kind of user tracking on the web. Our longitudinal study shows that user tracking can go as back as 2015, or even as 2013 (when the precursor of this technology was first introduced by Facebook). To put it simply, if a user creates for the first time a Facebook account today, Facebook could track her web browsing activity as far back as 2015.
arXiv:2208.00710v1 fatcat:3q4kteknq5dtlbampyyk4f7fnq

we.b

Demetris Antoniades, Iasonas Polakis, Georgios Kontaxis, Elias Athanasopoulos, Sotiris Ioannidis, Evangelos P. Markatos, Thomas Karagiannis
2011 Proceedings of the 20th international conference on World wide web - WWW '11  
Demetris Antoniades, Iasonas Polakis, Georgios Kontaxis, Elias Athanasopoulos and Evangelos P. Markatos are also with the University of Crete.  ... 
doi:10.1145/1963405.1963505 dblp:conf/www/AntoniadesPKAIMK11 fatcat:erguwpxjp5gatbsd6j4sk4quza
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