A multitude of wireless technologies are used by air traffic communication systems during different flight phases. From a conceptual perspective, all of them are insecure as security was never part of their design and the evolution of wireless security in aviation did not keep up with the state of the art. Recent contributions from academic and hacking communities have exploited this inherent vulnerability and demonstrated attacks on some of these technologies. However, these inputs revealed that a large discrepancy between the security perspective and the point of view of the aviation community exists. In this thesis, we aim to bridge this gap and combine wireless security knowledge with the perspective of aviation professionals to improve the safety of air traffic communication networks. To achieve this, we develop a comprehensive new threat model and analyse potential vulnerabilities, attacks, and countermeasures. Since not all of the required aviation knowledge is codified in academic publications, we examine the relevant aviation standards and also survey 242 international aviation experts. Besides extracting their domain knowledge, we analyse the awareness of the aviation community concerning the security of their wireless systems and collect expert opinions on the potential impact of concrete attack scenarios using insecure technologies. Based on our analysis, we propose countermeasures to secure air traffic communication that work transparently alongside existing technologies. We discuss, implement, and evaluate three different approaches based on physical and data link layer information obtained from live aircraft. We show that our countermeasures are able to defend against the injection of false data into air traffic control systems and can significantly and immediately improve the security of air traffic communication networks under the existing real-world constraints. Finally, we analyse the privacy consequences of open air traffic control protocols. We examine sensitive aircraft movements to detect large-scale events in the real world and illustrate the futility of current attempts to maintain privacy for aircraft owners.

Thesis (MA)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: A lack of English proficiency and failure to use standard phraseology played a role in two of the world’s largest aviation disasters in South Germany and Tenerife, respectively. As a result, the crucial role of effective pilot-ATC (air traffic controller) communication came under scrutiny and measures were put in place to ensure that aviation safety is not jeopardised by language-related problems. For example, the International Civil Aviation Organisation (ICAO) implemented English language proficiency standards and testing. The study reported in this thesis investigated the use of Aviation English and standard phraseology, which is used in radiotelephony communication by the operational aviation community. Aviation English consists of a range of operationally-relevant language functions and dialogue management, e.g. orders, requests, and offers to act; a blend of formulaic standard phraseology and plain or everyday speech if and when a non-routine situation occurs. Data on pilots’ and ATCs’ perceptions of the role of language in air traffic communication, their perspectives on English as lingua franca in aviation, and English language proficiency standards and testing were collected by means of a questionnaire. The respondents included full-time professional pilots (domestic and international flights), part-time professional pilots and pilots who fly for leisure, and ATCs in Air Traffic Navigation Service units that handle domestic and/or international flights. Recordings of on-site air traffic communication from two airport towers were obtained and were used to study the use of Aviation English and standard phraseology in pilot-ATC communication in South Africa. The results indicated that the majority of pilots and ATCs believe that language-related problems can cause fatal accidents and serious incidents. Pilots and ATCs in South Africa do experience threatening and potentially hazardous situations as a result of communication problems, however, they are confident that communication problems are resolved quickly and successfully in order to avoid accidents. The analysis of the voice recordings correlated with the pilots’ and ATCs’ perceptions that in spite of communication problems (languagerelated and non-language-related) occurring in South African airspace, pilots and ATCs have strategies in place to resolve them effectively and they are also able to use plain English to negotiate understanding and meaning. The majority of the respondents indicated that they agree that English should be used as the lingua franca in aviation around the world and they regard the English language proficiency of South African pilots and ATCs as satisfactory. The majority support ICAO’s English language proficiency standards and testing. The recordings presented a small percentage of transmissions with read-back/hear-back errors, but a substantial number of instances of radio distortions and background noise which interfered with the intelligibility of the transmissions, correlated with the results of the questionnaire. A small percentage of transmissions contained deviations from Aviation English and standard phraseology and/or the use of plain English. The researcher is of the opinion that this initial investigation into Aviation English serves to indicate some avenues for fruitful linguistic investigations into Aviation English and pilot-ATC communication in South Africa. / AFRIKAANSE OPSOMMING: Ontoereikende taalvaardigheid in Engels en nalating om standaard frases te gebruik, het bygedra tot twee van die ernstigste vliegongelukke in lugvaartgeskiedenis, naamlik in Suid-Duitsland en Tenerife, onderskeidelik. As gevolg van die ongelukke, het die kritieke rol van effektiewe kommunikasie tussen vlieëniers en lugverkeerleiers onder die loep gekom, en maatreëls is ingestel om te verseker dat lugvaartveiligheid nie deur taalverwante probleme benadeel word nie. Die Internasionale Burgerlugvaartorganisasie (IBLO) het byvoorbeeld, onder andere, taalvaardigheidsstandaarde en -toetsing vir vlieëniers en lugverkeerleiers ingestel. Die studie in hierdie tesis ondersoek die gebruik van Lugvaart-Engels (“Aviation English”) en standaard frases wat in radiokommunikasie deur die operasionele lugvaartgemeenskap gebruik word. Lugvaart-Engels bestaan uit ’n reeks operasioneel-toepaslike taalfunksies en gespreksbestuurmiddels, bv. instruksies, versoeke en ander handelinge; ’n mengsel van formele standaard frases en alledaagse Engels vir gevalle waar buitengewone of nie-roetine situasies hulle voordoen. ’n Vraelys is gebruik om inligting oor vlieëniers en lugverkeerleiers se sienings van die rol van taal in lugverkeerleiding in te samel, asook sienings oor die gebruik van Engels as lingua franca in lugverkeer en die IBLO se taalvaardigheidsstandaarde en toetsing vir vlieëniers en lugverkeerleiers. Die deelnemers sluit vlieëniers (voltyds en deeltyds, asook private en beroepsvlieëniers) in en lugverkeerleiers in lugverkeernavigasie-eenhede wat binnelandse en internasionale verkeer hanteer. Lewendige opnames wat van twee lughawetorings bekom is, is gebruik om taalverwante en ander kommunikasieprobleme tussen vlieëniers en lugverkeerleiers te ondersoek. Die resultate dui daarop dat die meerderheid vlieëniers en lugverkeerleiers van mening is dat taalverwante probleme tot noodlottige ongelukke en ernstige insidente kan lei. Daar is verder deur die deelnemers bevestig dat hulle dikwels in gevaarlike situasies beland waar kommunikasieprobleme tot die gevaar bygedra het, maar hulle is van mening dat kommunikasieprobleme in die Suid-Afrikaanse lugruim tydig en effektief opgelos word om ongelukke te vermy. Die opnames het met die bevindings van die vraelys ooreengestem en het aangedui dat, ten spyte van kommunikasieprobleme (taalverwant en nie-taalverwant) in die Suid-Afrikaanse lugruim, vlieëniers en lugverkeerleiers oor die vermoë beskik om sodanige probleme vinnig en suksesvol op te los. Dit het ook aan die lig gekom dat vlieëniers en lugverkeerleiers in Suid- Afrika daartoe in staat is om in alledaagse Engels te kommunikeer om enige onduidelikheid of buitengewone versoeke en instruksies te hanteer. Die meeste van die deelnemers meen dat vlieëniers en lugverkeerleiers in Suid-Afrika se taalvaardigheid in Engels bevredigend is en taalvaardigheidstandaarde en -toetsing word sterk ondersteun. Die lewendige opnames het ’n klein persentasie terugleesfoute bevat, maar ’n groot aantal gevalle van radiosteurings en agtergrondgeraas het met die hoorbaarheid en verstaanbaarheid van die kommunikasie ingemeng, wat met die resultate van die vraelys ooreengestem het. ’n Klein persentasie van die uitsendings het afwykings van Lugvaart-Engels en standaard frases en/of die gebruik van alledaagse Engels bevat. Die navorser is van mening dat hierdie studie die weg baan vir potensiële navorsing binne linguistiek ten opsigte van Lugvaart-Engels en die kommunikasie tussen vlieëniers en lugverkeerleiers in Suid-Afrika.

Air traffic communication is one of the most vital systems for air traffic management controllers. It is used every day to allow millions of people to travel safely and efficiently across the globe. But many of the systems considered industry-standard are used without any sort of encryption and authentication meaning that they are vulnerable to different wireless attacks. In this thesis vulnerabilities within an air traffic management system called ADS-B will be investigated. The structure and theory behind this system will be described as well as the reasons why ADS-B is unencrypted. Two attacks will then be implemented and performed in an open-source air traffic management simulator called openScope. ADS-B data from these attacks will be gathered and combined with actual ADS-B data from genuine aircrafts. The collected data will be cleaned and used for machine learning purposes where three different algorithms will be applied to detect attacks. Based on our findings, where two out of the three machine learning algorithms used were able to detect 99.99% of the attacks, we propose that machine learning algorithms should be used to improve ADS-B security. We also think that educating air traffic controllers on how to detect and handle attacks is an important part of the future of air traffic management.