Browsing by Author "Toosi, Topi"
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- Efficient fuzzing payload generation for mobile application security testing
Perustieteiden korkeakoulu | Master's thesis(2024-05-20) Helin, AntonThe topic of this Master's thesis focuses on developing efficient fuzzing payloads for security testing of Android and iOS mobile applications. Fuzzing is a technique which has mostly been used to detect crashes, errors and performance issues within an application by using random and unpredictable inputs. Modern security issues are on a higher abstraction level and require more specific inputs to be discovered and exploited. Many extremely efficient algorithms for fuzzing have been developed in the past, but the entropy is too large for them to be efficient, if purely random inputs are generated. This has led to web application fuzzer tools which have specialized inputs for finding specific target problems. The outcome of the research includes a method, which produces and selects payloads to use for fuzzing a mobile application. The variables that affect these are the input formats of the target app and the vulnerabilities that want to be searched for. Depending on the available static analysis and the user, their accuracy can be adjusted. Examples and evaluation of it's use in practice have been included for several important vulnerability types. The main problem that was solved consisted of constructing input languages of mobile applications in context-free grammar format and optimizing the generation of payloads from the grammars. As Android applications are Java-based, fuzzing payloads had to adhere to Java syntax in many cases, and serialized Java-classes are used to transmit data. One of the main improvements found in this research is generating payloads for Java programs which are specifically running as an Android application, leading to much more optimal use. This also does not require perfect knowledge of the source code of the application, so applications can be tested based on entirely public information on a regular Android device. This reduces the resources required for a testing environment. - METHOD FOR DETECTING AGING RELATED FAILURES OF PROCESS SENSORS VIA NOISE SIGNAL MEASUREMENT
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019) Toosi, Topi; Sirola, Miki; Laukkanen, Jarkko; Heeswijk, Mark van; Karhunen, JuhaIn this article we examine the methods for detecting and predicting aging related process sensor failures by analyzing the noise of the sensor output signal. The study uses data from non-differential and differential pressure transmitters used in the pressure and water level measurements of the reactor pressure vessels of units 1 and 2 of the Olkiluoto nuclear power plant in Finland. The article contains a review of the current methods for detection of sensor failures. Additionally, we present a new method for detecting changes in the sensor output signal. The method creates fingerprints of the power spectra of the sensors by using Principal Component Analysis (PCA). The changes in these fingerprints together with the measurements of the redundant sensors can be used to detect indications of some of the impending sensor failures. In the experimental study we are able to produce stable fingerprints for both the non-differential and differential pressure transmitters. Also, a potential failure in one of the differential pressure transmitters in Olkiluoto unit 2 is detected by inspecting the fingerprints and analyzing the spectral changes of the transmitter output signal. - Prosessianturien ikääntymisen havaitseminen kohinamittauksen avulla
Perustieteiden korkeakoulu | Master's thesis(2016-06-13) Toosi, TopiTässä diplomityössä tutkitaan menetelmiä prosessiantureiden ikääntymiseen liittyvän vikaantumisen havaitsemiseksi anturin kohinasignaalista. Tutkimuksen kohteena ovat ydinvoimalaitosyksiköiden Olkiluoto 1 ja Olkiluoto 2 pinnankorkeuden ja paineen mittaukseen käytetyt paine-ero- ja painelähettimet. Työssä esitellään kirjallisuudesta löytyviä menetelmiä vikaantumiseen liittyvien indikaattoreiden: anturin kalibraation ja vasteajan muutosten sekä signaalin resonanssipiikkien muutosten tunnistamiseksi anturin signaalin tehospektristä. Lisäksi työssä esitellään menetelmä anturit yksilöivien sormenjälkien muodostamiseksi spektristä pääkomponenttianalyysin avulla. Seuraamalla näiden sormenjälkien muutoksia sekä eroja samaa suuretta mittaavien rinnakkaisten anturien välillä voidaan tunnistaa merkkejä anturien vikaantumisesta. Kokeellisissa mittauksissa menetelmällä pystytään muodostamaan stabiileja sormenjälkiä pintamittauksen paine-erolähettimistä. Sormenjälkimenetelmän ja spektrin muutosten avulla löydetään merkkejä mahdollisesta vikaantumisesta yhdessä Olkiluoto 2 hienopinnan mittaukseen käytettävässä anturissa. - Tehokkaat laskentamenetelmät ChIP-Seq-sekvensointiaineistojen analysointiin
Perustieteiden korkeakoulu | Bachelor's thesis(2011-11-28) Toosi, Topi