Recently, Botnet has become one of the most severe threats on the Internet because it is hard to be prevented and cause huge losses. Prior intrusion detection system researches focused on traditional threats like virus, worm or Trojan. However, traditional intrusion detection system cannot detect Botnet activities before Botmasters launch final attack. In Botnet attack, in order to control a large amount of compromised hosts (bots), Botmasters use public internet service as communication and control channel (C&C Channel). IRC (Internet Relay Chat) is the most popular communication service which Botmasters use to send command to their bots. Once bots receive commands from Botmasters, they will do the corresponding abnormal action. It seems that Botnet activities could be detected by observing abnormal IRC traffic. In this paper, we will focus on IRC Server and, we will use four unique characteristics of abnormal channel, (1) the prefix of Botmaster communication in C&C channel, (2) the response messages of bots, (3) average response time from bots, and (4) average length of message, to detect abnormal Channel in IRC Server. We develop an on-line IRC IDS to detect abnormal IRC channel. In the proposed system, abnormal IRC channel can be detect and we can (1) identify the infected hosts (bots) and Botmaster in C&C Channel, (2) trackback the IP of Bots and Botmaster, (3) identify Bots before Botmasters launch final attack, and (4) find the pattern of abnormal channel. The experiments show that the proposed system can indeed detect abnormal IRC channel and find out bots and Botmaster.

Chemnitz, Techn. Univ., Diplomarb., 2005.

Seminario para optar al grado de Licenciado en Comunicación Social / El autor no autoriza el acceso a texto completo de su documento / A mediados de la década pasada, cuando Internet fue proclamado como el gran avance tecnológico que revolucionaría al ámbito de las comunicaciones y, por extensión, a la sociedad en su conjunto, no fueron pocas las voces que se mostraron escépticas ante colosal expectativa. Aseveraron que el tiempo demostraría lo contrario, que se trataba de una invención mediática más, que sus supuestas bondades se reducían a simple parafernalia digital, y que, tal como sucedió en su momento con el cine, la radio y la televisión, caería por su propio peso. Pasada casi una década desde aquellos días, la incredulidad ilustrada no trascendió la anécdota y los hechos han terminado por dar la razón a quienes soñaron en la red a la aldea global que el sociólogo Marshall McLuhan había profetizado en los años ’60. Es cierto. Internet se ha convertido en una herramienta imprescindible de este orbe globalizado, y nuestro mundo tal como hoy lo conocemos no puede ser entendido sin su existencia. Y tal como se anunciaba, la teleñara informática ha traspasado las barreras de la información, enebrando sus hilos en todo aspecto de la vida humana. Ni siquiera la esfera privada escapa a su influencia y ya no resulta extraño que comunidades enteras se hayan erigido en invisibles pilares de códigos binarios. “¿Comunidades no físicas? ¿Es eso posible?”, se preguntarán los mismos señores escépticos, y en cualquier parte del planeta hallarán la respuesta. Incluso aquí en Chile, con miles de pequeñas tribus de internautas que en el anonimato arácnido construyen un nuevo concepto de grupo social, aquél donde la interacción humana deja atrás milenios de obstáculos, etiquetas y discriminaciones. Aquél que, a continuación, hemos de presentar.

The concept of community has been of great importance to sociologists throughout the discipline's history. There has been numerous definitions used in research. However, according to the literature, most agree that community must consist of geographical proximity, regular interactions, and shared goals. These definitions, and any consensus, are again being challenged by the creation of new communicative technologies. In particular, with the creation of new social spaces by computer technologies such as the Internet, the potential exists for community to occur in many new ways. This paper looks at the types of community that can exist in the various social spaces created by the Internet. These spaces are conceptualized and explained comparing the various ways and types of communication that are occurring in the various facets of Internet. The literature indicates that community is occurring in some of these Internet technologies, such as USENET. However, no such literature exists for IRC networks. This research focuses on an examination of the type of community that occurs on the Internet's synchronous Internet Relay Chat network using computer-mediated-communication. Naturalistic inquiry is used to examine how community exists in two separate channels of an Internet Relay Chat network. The concepts of geographical proximity, regular interaction, and shared goals are examined in relation to this technology. In a final analysis, the importance in examining the community occurring in these new social spaces is detailed. This type of social space is fast becoming a very important area for researchers as Internet usage is growing daily and becoming more prevalent in everyday society. / Master of Science

No description available.

No description available.

L’influence du champ magnétique sur l’évolution stellaire reste à déterminer, notamment lors de la transition de la branche asymptotique des géantes (AGB) vers les Nébuleuses planétaires (PN) des étoiles de masse intermédiaire et solaire, et de la transition des supergéantes rouges (RSG) vers le stade des supernova (SN) ouWolf Rayet (WR) pour les étoiles massives. Le champ magnétique joue probablement un rôle important dans le processus de perte de masse et de leur changement de morphologie, passant d’un objet sphérique à un objet asymétrique avec émissions de jets de matière. Pendant ma thèse j’ai étudié l’enveloppe circumstellaire de Betelgeuse, une RSG. J’ai utilisé l’antenne radio IRAM-30m, pour réaliser le premier relevé spectral à 1,3 et 3 mm. Il en ressort que Betelgeuse est chimiquement jeune ; seulement 7 espèces ont été détectées. Cependant, pour la première fois lemaser SiO a été détecté pour cette étoile, ce qui pourrait permettre d’estimer le champ magnétique de l’enveloppe de cette étoile. La seconde partie de ma thèse a été d’estimer l’intensité du champ magnétique pour un échantillon d’AGBs et PNe grâce au radical CN sensible à l’effet Zeeman. L’intensité du champ magnétique selon l’axe de visé (Blos ) est estimée entre -7,5 et 14,2 mG. En comparant avec de précédentes études à toutes les longueurs d’onde, nous pouvons conclure que le champ magnétique décroit en 1/r où r est la distance à l’étoile. Pour l’étoile IRC+10216 le champ magnétique est estimé pour plusieurs positions de son enveloppe allant de -7,2 à 9,5 mG : Blos n’est pas homogène et aligné dans l’enveloppe. / The influence of themagnetic field on the stellar evolutions has still to be determined, particularly for the transition from the asymptotic giant branch (AGB) to planetary nebulae (PN) for intermediate and solar mass stars, and the transition from red supergiant (RSG) to supernova (SN) or Wolf Rayet (WR) for massive stars. The magnetic field plays likely an important role in the mass loss process, and the star morphology changes from a spherical to an asymmetric object with outflows. During my thesis, I studied the circumstellar envelope of Betelgeuse, an RSG. I used the radio telescope IRAM-30m, to make a spectral survey at 1,3 and 3 mm.We detect only 7 species hence revealing that Betelgeuse is chemically young. However we detect for the first time the SiO maser, which will make possible to estimate themagnetic field in the envelope of this star. The second part of my thesis was to estimate the intensity of the magnetic field for a sample of AGBs and PNe using the CN radical sensitive to the Zeeman effect. The intensity of the magnetic field along the line of sight (Blos) is estimated between -7.5 and 14.2 mG. Comparing with previous studies at all wavelengths, we can conclude that the magnetic field decreases in 1/r with r the distance to the star. For the star IRC+10216, Blos is estimated for several positions of the envelope between -7.2 and 9.5 mG : Blos is not homogeneous and aligned in the CSE.

Das Information Resource Center (IRC) des amerikanischen Generalkonsulats in Leipzig spielt seit vielen Jahren eine aktive Rolle im bibliothekarischen Netzwerk der Bundesländer Sachsen, Sachsen-Anhalt und Thüringen. Zurzeit besteht ein aktives Arbeitsverhältnis mit rund 40 Bibliotheken, zu denen wissenschaftliche und öffentliche Bibliotheken sowie Schulbibliotheken gehören, aber auch die Deutsche Nationalbibliothek in Leipzig. Seit 2006 wurden im Rahmen des America@YourLibrary (A@YL) Programms der USBotschaft in Berlin 5 Bibliotheken, nämlich die Stadtbibliothek Leipzig, die Stadtbibliothek Chemnitz, die Bibliothek der Europa-Schule in Görlitz, die Stadtbibliothek in Magdeburg, und die Stadtund Landesbibliothek in Erfurt A@YL, Partnerbibliotheken des US-Generalkonsulats...

I have developed a new general-purpose deterministic 2D radiative transfer code for astrophysical dusty environments named LELUYA (www.leluya.org). It can provide the solution to an arbitrary axially symmetric multi-grain dust distribution around an arbitrary heating source. By employing a new numerical method, the implemented algorithm automatically traces the dust density and optical depth gradients, creating the optimal unstructured triangular grid. The radiative transfer equation includes dust scattering, absorption and emission. Unique to LELUYA is also its ability to self-consistently reshape the sublimation/condensation dust cavity around the source to accommodate for the anisotropic diffuse radiation. LELUYAs capabilities are demonstrated in the study of the asymptotic giant branch (AGB) star IRC+10011. The stellar winds emanating from AGB stars are mostly spherically symmetric, but they evolve into largely asymmetric planetary nebulae during later evolutionary phases. The initiation of this symmetry breaking process is still unexplained. IRC+10011 represents a rare example of a clearly visible asymmetry in high-resolution near-infrared images of the circumstellar dusty AGB wind. LELUYA shows that this asymmetry is produced by two bipolar cones with 1/r0.5 density profile, imbedded in the standard 1/r2 dusty wind profile. The cones are still breaking though the 1/r2 wind, suggesting they are driven by bipolar jets. They are about 200 years old, thus a very recent episode in the final phase of AGB evolution before turning into a proto-planetary nebula, where the jets finally break out from the confining spherical wind. IRC+10011 provides the earliest example of this symmetry breaking thus far.

Over the past decade, webcriminality has become a real issue. Because they allow the botmasters to control hundreds to millions of machines, botnets became the first-choice attack platform for the network attackers, to launch distributed denial of service attacks, steal sensitive information and spend spam emails. This work aims at designing and implementing a honeynet, specific to IRC bots. Our system works in 3 phasis: (1) binaries collection, (2) simulation, and (3) activity capturing and monitoring. Our phase 2 simulation uses an IRC redirection to extract the connection information thanks to a IRC redirection (using a DNS redirection and a "fakeserver"). In phase 3, we use the information previously extracted to launch our honeyclient, which will capture and monitor the traffic on the C&C channel. Thanks to our honeynet, we create a database of the activity of IRC botnets (their connection characteristics, commands on the C&C ), and hope to learn more about their behavior and the underground market they create.