836 research outputs found
A user-oriented network forensic analyser: the design of a high-level protocol analyser
Network forensics is becoming an increasingly important tool in the investigation of cyber and computer-assisted crimes. Unfortunately, whilst much effort has been undertaken in developing computer forensic file system analysers (e.g. Encase and FTK), such focus has not been given to Network Forensic Analysis Tools (NFATs). The single biggest barrier to effective NFATs is the handling of large volumes of low-level traffic and being able to exact and interpret forensic artefacts and their context – for example, being able extract and render application-level objects (such as emails, web pages and documents) from the low-level TCP/IP traffic but also understand how these applications/artefacts are being used. Whilst some studies and tools are beginning to achieve object extraction, results to date are limited to basic objects. No research has focused upon analysing network traffic to understand the nature of its use – not simply looking at the fact a person requested a webpage, but how long they spend on the application and what interactions did they have with whilst using the service (e.g. posting an image, or engaging in an instant message chat). This additional layer of information can provide an investigator with a far more rich and complete understanding of a suspect’s activities. To this end, this paper presents an investigation into the ability to derive high-level application usage characteristics from low-level network traffic meta-data. The paper presents a three application scenarios – web surfing, communications and social networking and demonstrates it is possible to derive the user interactions (e.g. page loading, chatting and file sharing ) within these systems. The paper continues to present a framework that builds upon this capability to provide a robust, flexible and user-friendly NFAT that provides access to a greater range of forensic information in a far easier format
Sonification of Network Traffic Flow for Monitoring and Situational Awareness
Maintaining situational awareness of what is happening within a network is
challenging, not least because the behaviour happens within computers and
communications networks, but also because data traffic speeds and volumes are
beyond human ability to process. Visualisation is widely used to present
information about the dynamics of network traffic dynamics. Although it
provides operators with an overall view and specific information about
particular traffic or attacks on the network, it often fails to represent the
events in an understandable way. Visualisations require visual attention and so
are not well suited to continuous monitoring scenarios in which network
administrators must carry out other tasks. Situational awareness is critical
and essential for decision-making in the domain of computer network monitoring
where it is vital to be able to identify and recognize network environment
behaviours.Here we present SoNSTAR (Sonification of Networks for SiTuational
AwaReness), a real-time sonification system to be used in the monitoring of
computer networks to support the situational awareness of network
administrators. SoNSTAR provides an auditory representation of all the TCP/IP
protocol traffic within a network based on the different traffic flows between
between network hosts. SoNSTAR raises situational awareness levels for computer
network defence by allowing operators to achieve better understanding and
performance while imposing less workload compared to visual techniques. SoNSTAR
identifies the features of network traffic flows by inspecting the status flags
of TCP/IP packet headers and mapping traffic events to recorded sounds to
generate a soundscape representing the real-time status of the network traffic
environment. Listening to the soundscape allows the administrator to recognise
anomalous behaviour quickly and without having to continuously watch a computer
screen.Comment: 17 pages, 7 figures plus supplemental material in Github repositor
Privacy-Friendly Collaboration for Cyber Threat Mitigation
Sharing of security data across organizational boundaries has often been
advocated as a promising way to enhance cyber threat mitigation. However,
collaborative security faces a number of important challenges, including
privacy, trust, and liability concerns with the potential disclosure of
sensitive data. In this paper, we focus on data sharing for predictive
blacklisting, i.e., forecasting attack sources based on past attack
information. We propose a novel privacy-enhanced data sharing approach in which
organizations estimate collaboration benefits without disclosing their
datasets, organize into coalitions of allied organizations, and securely share
data within these coalitions. We study how different partner selection
strategies affect prediction accuracy by experimenting on a real-world dataset
of 2 billion IP addresses and observe up to a 105% prediction improvement.Comment: This paper has been withdrawn as it has been superseded by
arXiv:1502.0533
An explainable AI-based intrusion detection system for DNS over HTTPS (DoH) attacks
Over the past few years, Domain Name Service (DNS) remained a prime target for hackers as it enables them to gain first entry into networks and gain access to data for exfiltration. Although the DNS over HTTPS (DoH) protocol has desirable properties for internet users such as privacy and security, it also causes a problem in that network administrators are prevented from detecting suspicious network traffic generated by malware and malicious tools. To support their efforts in maintaining a secure network, in this paper, we have implemented an explainable AI solution using a novel machine learning framework. We have used the publicly available CIRA-CIC-DoHBrw-2020 dataset for developing an accurate solution to detect and classify the DNS over HTTPS attacks. Our proposed balanced and stacked Random Forest achieved very high precision (99.91%), recall (99.92%) and F1 score (99.91%) for the classification task at hand. Using explainable AI methods, we have additionally highlighted the underlying feature contributions in an attempt to provide transparent and explainable results from the model
Non-intrusive anomaly detection for encrypted networks
The use of encryption is steadily increasing. Packet payloads that are encrypted are becoming increasingly difficult to analyze using IDSs. This investigation uses a new non-intrusive IDS approach to detect network intrusions using a K-Means clustering methodology. It was found that this approach was able to detect many intrusions for these datasets while maintaining the encrypted confidentiality of packet information. This work utilized the KDD \u2799 and NSL-KDD evaluation datasets for testing
Salattujen komento- ja ohjauskanavien havaitseminen verkkosormenjälkien avulla
The threat landscape of the Internet has evolved drastically into an environment where malware are increasingly developed by financially motivated cybercriminal groups who mirror legitimate businesses in their structure and processes. These groups develop sophisticated malware with the aim of transforming persistent control over large numbers of infected machines into profit. Recent developments have shown that malware authors seek to hide their Command and Control channels by implementing custom application layer protocols and using custom encryption algorithms. This technique effectively thwarts conventional pattern-based detection mechanisms.
This thesis presents network fingerprints, a novel way of performing network-based detection of encrypted Command and Control channels. The goal of the work was to produce a proof of concept system that is able to generate accurate and reliable network signatures for this purpose. The thesis presents and explains the individual phases of an analysis pipeline that was built to process and analyze malware network traffic and to produce network fingerprint signatures.
The analysis system was used to generate network fingerprints that were deployed to an intrusion detection system in real-world networks for a test period of 17 days. The experimental phase produced 71 true positive detections and 9 false positive detections, and therefore proved that the established technique is capable of performing detection of targeted encrypted Command and Control channels. Furthermore, the effects on the performance of the underlying intrusion detection system were measured. These results showed that network fingerprints induce an increase of 2-9% to the packet loss and a small increase to the overall computational load of the intrusion detection system.Internetin uhkaympäristön radikaalin kehittymisen myötä edistyksellisiä haittaohjelmia kehittävät kyberrikollisryhmät ovat muuttuneet järjestäytyneiksi ja taloudellista voittoa tavoitteleviksi organisaatioiksi. Nämä rakenteiltaan ja prosesseiltaan laillisia yrityksiä muistuttavat organisaatiot pyrkivät saastuttamaan suuria määriä tietokoneita ja saavuttamaan yhtämittaisen hallintakyvyn. Tutkimukset ovat osoittaneet, että tuntemattomien salausmenetelmien ja uusien sovellustason protokollien käyttö haittaohjelmien komento- ja hallintakanavien piilottamiseksi tietoverkoissa ovat kasvussa. Tämän kaltaiset tekniikat vaikeuttavat oleellisesti perinteisiä toistuviin kuvioihin perustuvia havaitsemismenetelmiä.
Tämä työ esittelee salattujen komento- ja hallintakanavien havaitsemiseen suunnitellun uuden konseptin, verkkosormenjäljet. Työn tavoitteena oli toteuttaa prototyyppijärjestelmä, joka analysoi ja prosessoi haittaohjelmaliikennettä, sekä kykenee tuottamaan tarkkoja ja tehokkaita haittaohjelmakohtaisia verkkosormenjälkitunnisteita. Työ selittää verkkosormenjälkien teorian ja käy yksityiskohtaisesti läpi kehitetyn järjestelmän eri osiot ja vaiheet.
Järjestelmästä tuotetut verkkosormenjäljet asennettiin 17 päiväksi oikeisiin tietoverkkoihin osaksi tunkeilijan havaitsemisjärjestelmää. Testijakso tuotti yhteensä 71 oikeaa haittaohjelmahavaintoa sekä 9 väärää havaintoa. Menetelmän käyttöönoton vaikutukset tunkeilijan havaitsemisjärjestelmän suorituskykyyn olivat 2 – 9 % kasvu pakettihäviössä ja pieni nousu laskennallisessa kokonaiskuormituksessa. Tulokset osoittavat, että kehitetty järjestelmä kykenee onnistuneesti analysoimaan haittaohjelmaliikennettä sekä tuottamaan salattuja komento- ja hallintakanavia havaitsevia verkkosormenjälkiä
Controlled Data Sharing for Collaborative Predictive Blacklisting
Although sharing data across organizations is often advocated as a promising
way to enhance cybersecurity, collaborative initiatives are rarely put into
practice owing to confidentiality, trust, and liability challenges. In this
paper, we investigate whether collaborative threat mitigation can be realized
via a controlled data sharing approach, whereby organizations make informed
decisions as to whether or not, and how much, to share. Using appropriate
cryptographic tools, entities can estimate the benefits of collaboration and
agree on what to share in a privacy-preserving way, without having to disclose
their datasets. We focus on collaborative predictive blacklisting, i.e.,
forecasting attack sources based on one's logs and those contributed by other
organizations. We study the impact of different sharing strategies by
experimenting on a real-world dataset of two billion suspicious IP addresses
collected from Dshield over two months. We find that controlled data sharing
yields up to 105% accuracy improvement on average, while also reducing the
false positive rate.Comment: A preliminary version of this paper appears in DIMVA 2015. This is
the full version. arXiv admin note: substantial text overlap with
arXiv:1403.212
Using HTML5 to Prevent Detection of Drive-by-Download Web Malware
The web is experiencing an explosive growth in the last years. New
technologies are introduced at a very fast-pace with the aim of narrowing the
gap between web-based applications and traditional desktop applications. The
results are web applications that look and feel almost like desktop
applications while retaining the advantages of being originated from the web.
However, these advancements come at a price. The same technologies used to
build responsive, pleasant and fully-featured web applications, can also be
used to write web malware able to escape detection systems. In this article we
present new obfuscation techniques, based on some of the features of the
upcoming HTML5 standard, which can be used to deceive malware detection
systems. The proposed techniques have been experimented on a reference set of
obfuscated malware. Our results show that the malware rewritten using our
obfuscation techniques go undetected while being analyzed by a large number of
detection systems. The same detection systems were able to correctly identify
the same malware in its original unobfuscated form. We also provide some hints
about how the existing malware detection systems can be modified in order to
cope with these new techniques.Comment: This is the pre-peer reviewed version of the article: \emph{Using
HTML5 to Prevent Detection of Drive-by-Download Web Malware}, which has been
published in final form at \url{http://dx.doi.org/10.1002/sec.1077}. This
article may be used for non-commercial purposes in accordance with Wiley
Terms and Conditions for Self-Archivin
- …