Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 11) Show all publications
Afzal, Z. (2020). Life of a Security Middlebox: Challenges with Emerging Protocols and Technologies. (Doctoral dissertation). Karlstad: Karlstads universitet
Open this publication in new window or tab >>Life of a Security Middlebox: Challenges with Emerging Protocols and Technologies
2020 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The Internet of today has intermediary devices known as middleboxes that perform more functions than the normal packet forwarding function of a router. Security middleboxes are a subset of these middleboxes and face an increasingly difficult task to perform their functions correctly. These middleboxes make many assumptions about the traffic that may not hold true any longer with the advent of new protocols such as MPTCP and technologies like end-to-end encryption.

The work in this thesis focuses on security middleboxes and the challenges they face. We develop methods and solutions to help these security middleboxes continue to function correctly. In particular, we investigate the case of using MPTCP over traditional security infrastructure as well as the case of end-to-end encryption. We study how practical it is to evade a security middlebox by fragmenting and sending traffic across multiple paths using MPTCP. We then go on to propose possible solutions to detect such attacks and implement them. The potential MPTCP scenario where security middleboxes only have access to part of the traffic is also investigated and addressed. Moreover, the thesis contributes a machine learning based approach to help security middleboxes detect malware in encrypted traffic without decryption.

Abstract [en]

The Internet of today has intermediary devices known as middleboxes thatperform more functions than the normal packet forwarding function of arouter. Security middleboxes are a subset of these middleboxes and face anincreasingly difficult task to perform their functions correctly in the wake ofemerging protocols and technologies on the Internet. Security middleboxesmake many assumptions about the traffic, e.g., they assume that traffic froma single connection always arrives over the same path and they often expectto observe plaintext data. These along with many other assumptions may nothold true any longer with the advent of new protocols such as MPTCP andtechnologies like end-to-end encryption.

The work in this thesis focuses on security middleboxes and the challengesthey face in performing their functions in an evolving Internet where newnetworking protocols and technologies are regularly introduced. We developmethods and solutions to help these security middleboxes continue to functioncorrectly. In particular, we investigate the case of using MPTCP overtraditional security infrastructure as well as the case of end-to-end encryption.

We study how practical it is to evade a security middlebox by fragmentingand sending traffic across multiple paths using MPTCP. Attack traffic that isgenerated from a self-developed tool is used to evaluate such attacks to showthat these attacks are feasible. We then go on to propose possible solutionsto detect such attacks and implement them. The potential MPTCP scenariowhere security middleboxes only have access to part of the traffic is also investigated.Furthermore, we propose and implement an algorithm to performintrusion detection in such situations. Moreover, the thesis contributes a machinelearning based approach to help security middleboxes detect malware inencrypted traffic without decryption.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2020. p. 26
Series
Karlstad University Studies, ISSN 1403-8099 ; 2020:10
Keywords
network security, TCP, MPTCP, IDS, Snort, edit-distance, encryption
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Computer Science
Identifiers
urn:nbn:se:kau:diva-76291 (URN)978-91-7867-093-2 (ISBN)978-91-7867-103-8 (ISBN)
Public defence
2020-02-28, 21A342, Eva Erikssonsalen, Karlstad, 10:15 (English)
Opponent
Supervisors
Available from: 2020-02-05 Created: 2020-01-14 Last updated: 2020-02-05Bibliographically approved
Afzal, Z., Garcia, J., Lindskog, S. & Brunström, A. (2019). Using Partial Signatures in Intrusion Detection for Multipath TCP. In: Aslan Askarov, René Rydhof Hansen, Willard Rafnsson (Ed.), Secure IT-systems: 24th Nordic Conference, NordSec 2019, Aalborg, Denmark, November 18–20, 2019, Proceedings. Paper presented at NordSec2019: 24th Nordic Conference on Secure IT Systems, 18-20 November, 2019, Aalborg, Denmark, (pp. 71-86). Cham, Switzerland: Springer
Open this publication in new window or tab >>Using Partial Signatures in Intrusion Detection for Multipath TCP
2019 (English)In: Secure IT-systems: 24th Nordic Conference, NordSec 2019, Aalborg, Denmark, November 18–20, 2019, Proceedings / [ed] Aslan Askarov, René Rydhof Hansen, Willard Rafnsson, Cham, Switzerland: Springer, 2019, p. 71-86Conference paper, Published paper (Refereed)
Abstract [en]

Traditional security mechanisms such as signature basedintrusion detection systems (IDSs) attempt to find a perfect match of aset of signatures in network traffic. Such IDSs depend on the availabilityof a complete application data stream. With emerging protocols such asMultipath TCP (MPTCP), this precondition cannot be ensured, result-ing in false negatives and IDS evasion. On the other hand, if approximatesignature matching is used instead in an IDS, a potentially high numberof false positives make the detection impractical. In this paper, we showthat, by using a specially tailored partial signature matcher and knowl-edge about MPTCP semantics, the Snort3 IDS can be empowered withpartial signature detection. Additionally, we uncover the type of Snort3rules suitable for the task of partial matching. Experimental results withthese rules show a low false positive rate for benign traffic and highdetection coverage for attack traffic.

Place, publisher, year, edition, pages
Cham, Switzerland: Springer, 2019
Series
Lecture Notes in Computer Science, ISSN 0302-9743 ; 11875
National Category
Engineering and Technology
Research subject
Computer Science; Computer Science
Identifiers
urn:nbn:se:kau:diva-75755 (URN)10.1007/978-3-030-35055-0_5 (DOI)
Conference
NordSec2019: 24th Nordic Conference on Secure IT Systems, 18-20 November, 2019, Aalborg, Denmark,
Available from: 2019-11-14 Created: 2019-11-14 Last updated: 2020-01-14Bibliographically approved
Afzal, Z., Garcia, J., Lindskog, S. & Brunström, A. (2018). Slice Distance: An Insert-Only Levenshtein Distance with a Focus on Security Applications. In: Proceedings of NTMS 2018 Conference and Workshop: . Paper presented at 9th IFIP International Conference on New Technologies, Mobility and Security, 26-28 February 2018, Paris, France (pp. 1-5). New York: IEEE
Open this publication in new window or tab >>Slice Distance: An Insert-Only Levenshtein Distance with a Focus on Security Applications
2018 (English)In: Proceedings of NTMS 2018 Conference and Workshop, New York: IEEE, 2018, p. 1-5Conference paper, Published paper (Refereed)
Abstract [en]

Levenshtein distance is well known for its use in comparing two strings for similarity. However, the set of considered edit operations used when comparing can be reduced in a number of situations. In such cases, the application of the generic Levenshtein distance can result in degraded detection and computational performance. Other metrics in the literature enable limiting the considered edit operations to a smaller subset. However, the possibility where a difference can only result from deleted bytes is not yet explored. To this end, we propose an insert-only variation of the Levenshtein distance to enable comparison of two strings for the case in which differences occur only because of missing bytes. The proposed distance metric is named slice distance and is formally presented and its computational complexity is discussed. We also provide a discussion of the potential security applications of the slice distance.

Place, publisher, year, edition, pages
New York: IEEE, 2018
Keywords
Measurement, Pattern matching, Time complexity, Transforms, Security, DNA
National Category
Computer Sciences
Research subject
Computer Science
Identifiers
urn:nbn:se:kau:diva-67012 (URN)10.1109/NTMS.2018.8328718 (DOI)000448864200049 ()978-1-5386-3662-6 (ISBN)978-1-5386-3663-3 (ISBN)
Conference
9th IFIP International Conference on New Technologies, Mobility and Security, 26-28 February 2018, Paris, France
Projects
HITS, 4707
Funder
Knowledge Foundation, 4707
Available from: 2018-04-17 Created: 2018-04-17 Last updated: 2020-01-14Bibliographically approved
Afzal, Z. (2017). Towards Secure Multipath TCP Communication. (Licentiate dissertation). Karlstad: Karlstads universitet
Open this publication in new window or tab >>Towards Secure Multipath TCP Communication
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The evolution in networking coupled with an increasing demand to improve user experience has led to different proposals to extend the standard TCP. Multipath TCP (MPTCP) is one such extension that has the potential to overcome few inherent limitations in the standard TCP. While MPTCP's design and deployment progresses, most of the focus has been on its compatibility. The security aspect is confined to making sure that the MPTCP protocol itself offers the same security level as the standard TCP.

The topic of this thesis is to investigate the unexpected security implications raised by using MPTCP in the traditional networking environment. The Internet of today has security middle-boxes that perform traffic analysis to detect intrusions and attacks. Such middle-boxes make use of different assumptions about the traffic, e.g., traffic from a single connection always arrives along the same path. This along with many other assumptions may not be true anymore with the advent of MPTCP as traffic can be fragmented and sent over multiple paths simultaneously.

We investigate how practical it is to evade a security middle-box by fragmenting and sending traffic across multiple paths using MPTCP. Realistic attack traffic is used to evaluate such attacks against Snort IDS to show that these attacks are feasible. We then go on to propose possible solutions to detect such attacks and implement them in an MPTCP proxy. The proxy aims to extend the MPTCP performance advantages to servers that only support standard TCP, while ensuring that intrusions can be detected as before. Finally, we investigate the potential MPTCP scenario where security middle-boxes only have access to some of the traffic. We propose and implement an algorithm to perform intrusion detection in such situations and achieve a nearly 90% detection accuracy. Another contribution of this work is a tool, that converts IDS rules into equivalent attack traffic to automate the evaluation of a middle-box.

Abstract [en]

Multipath TCP (MPTCP) is an extension to standard TCP that is close to being standardized. The design of the protocol is progressing, but most of the focus has so far been on its compatibility. The security aspect is confined to making sure that the MPTCP protocol itself offers the same security level as standard TCP. The topic of this thesis is to investigate the unexpected security implications raised by using MPTCP in a traditional networking environment. Today, the security middleboxes make use of different assumptions that may not be true anymore with the advent of MPTCP.We investigate how practical it is to evade a security middlebox by fragmenting and sending traffic across multiple paths using MPTCP. Realistic attack traffic generated from a tool that is also presented in this thesis is used to show that these attacks are feasible. We then go on to propose possible solutions to detect such attacks and implement them in an MPTCP proxy. The proxy aims to extend secure MPTCP performance advantages. We also investigate the MPTCP scenario where security middleboxes can only observe some of the traffic. We propose and implement an algorithm to perform intrusion detection in such situations and achieve a high detection accuracy.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2017. p. 91
Series
Karlstad University Studies, ISSN 1403-8099 ; 2017:12
Keywords
network security, MPTCP, TCP, IDS, snort, edit-distance
National Category
Computer Sciences
Research subject
Computer Science
Identifiers
urn:nbn:se:kau:diva-48172 (URN)978-91-7063-763-6 (ISBN)978-91-7063-764-3 (ISBN)
Presentation
2017-04-28, 1B364, Karlstad, 13:00 (English)
Opponent
Supervisors
Projects
HITS
Available from: 2017-04-10 Created: 2017-03-17 Last updated: 2019-12-02Bibliographically approved
Afzal, Z., Rossebø, J., Chowdhury, M. & Talha, B. (2016). A Wireless Intrusion Detection System for 802.11 networks. In: PROCEEDINGS OF THE 2016 IEEE INTERNATIONAL CONFERENCE ON WIRELESS COMMUNICATIONS, SIGNAL PROCESSING AND NETWORKING (WISPNET): . Paper presented at International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), Chennai, India, 23-25 March 2016 (pp. 828-834). IEEE
Open this publication in new window or tab >>A Wireless Intrusion Detection System for 802.11 networks
2016 (English)In: PROCEEDINGS OF THE 2016 IEEE INTERNATIONAL CONFERENCE ON WIRELESS COMMUNICATIONS, SIGNAL PROCESSING AND NETWORKING (WISPNET), IEEE, 2016, p. 828-834Conference paper, Published paper (Refereed)
Abstract [en]

Wireless local area networks (WLANs) deployment is increasing rapidly. At the same time, WLANs have become an attractive target for many potential attackers. In spite of that, the de facto standard used to implement most WLANs (IEEE 802.11) has what appear to be residual vulnerabilities related to identity spoofing. In this paper, a pragmatic study of two common attacks on the standard is conducted. These attacks are then implemented on test beds to learn attack behavior. Finally, novel attack signatures and techniques to detect these attacks are devised and implemented in a proof of concept Wireless Intrusion Detection System (WIDS).

Place, publisher, year, edition, pages
IEEE, 2016
National Category
Computer Sciences
Research subject
Computer Science
Identifiers
urn:nbn:se:kau:diva-46218 (URN)10.1109/WiSPNET.2016.7566249 (DOI)000388601800172 ()978-1-4673-9338-6 (ISBN)
Conference
International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), Chennai, India, 23-25 March 2016
Available from: 2016-09-19 Created: 2016-09-19 Last updated: 2019-12-02Bibliographically approved
Afzal, Z. & Lindskog, S. (2016). IDS rule management made easy. In: Electronics, Computers and Artificial Intelligence (ECAI), 2016 8th International Conference on: . Paper presented at 8th International Conference on Electronics, Computers and Artificial Intelligence (ECAI), 30 June-2 July 2016, Ploiesti, Romania. IEEE
Open this publication in new window or tab >>IDS rule management made easy
2016 (English)In: Electronics, Computers and Artificial Intelligence (ECAI), 2016 8th International Conference on, IEEE, 2016Conference paper, Published paper (Refereed)
Abstract [en]

Signature-based intrusion detection systems (IDSs) are commonly utilized in enterprise networks to detect and possibly block a wide variety of attacks. Their application in industrial control systems (ICSs) is also growing rapidly as modem ICSs increasingly use open standard protocols instead of proprietary. Due to an ever changing threat landscape, the rulesets used by these IDSs have grown large and there is no way to verify their precision or accuracy. Such broad and non-optimized rulesets lead to false positives and an unnecessary burden on the IDS, resulting in possible degradation of the security. This work proposes a methodology consisting of a set of tools to help optimize the IDS rulesets and make rule management easier. The work also provides attack traffic data that is expected to benefit the task of IDS assessment.

Place, publisher, year, edition, pages
IEEE, 2016
Series
International Conference on Electronics Computers and Artificial Intelligence, ISSN 2378-7147
National Category
Computer Sciences
Identifiers
urn:nbn:se:kau:diva-48016 (URN)10.1109/ECAI.2016.7861119 (DOI)000402541200055 ()978-1-5090-2048-5 (ISBN)978-1-5090-2047-8 (ISBN)
Conference
8th International Conference on Electronics, Computers and Artificial Intelligence (ECAI), 30 June-2 July 2016, Ploiesti, Romania
Projects
HITS, 4707
Funder
Knowledge Foundation
Available from: 2017-02-24 Created: 2017-02-24 Last updated: 2020-01-14Bibliographically approved
Afzal, Z., Lindskog, S., Brunström, A. & Lidén, A. (2016). Towards Multipath TCP Aware Security Technologies. In: 2016 8th IFIP International Conference onNew Technologies, Mobility and Security (NTMS): . Paper presented at 8th IFIP International Conference on New Technologies, Mobility and Security (NTMS), Larnaca, Cyprus 21-23 November 2016 (pp. 1-8). New York: IEEE
Open this publication in new window or tab >>Towards Multipath TCP Aware Security Technologies
2016 (English)In: 2016 8th IFIP International Conference onNew Technologies, Mobility and Security (NTMS), New York: IEEE, 2016, p. 1-8Conference paper, Published paper (Refereed)
Abstract [en]

Multipath TCP (MPTCP) is a proposed extension to TCP that enables a number of performance advantages that have not been offered before. While the protocol specification is close to being finalized, there still remain some unaddressed challenges regarding the deployment and security implications of the protocol. This work attempts to tackle some of these concerns by proposing and implementing MPTCP aware security services and deploying them inside a proof of concept MPTCP proxy. The aim is to enable hosts, even those without native MPTCP support, to securely benefit from the MPTCP performance advantages. Our evaluations show that the security services that are implemented enable proper intrusion detection and prevention to thwart potential attacks as well as threshold rules to prevent denial of service (DoS) attacks.

Place, publisher, year, edition, pages
New York: IEEE, 2016
National Category
Computer Sciences
Identifiers
urn:nbn:se:kau:diva-47594 (URN)10.1109/NTMS.2016.7792485 (DOI)000391578700063 ()978-1-5090-2914-3 (ISBN)
Conference
8th IFIP International Conference on New Technologies, Mobility and Security (NTMS), Larnaca, Cyprus 21-23 November 2016
Projects
HITS, 4707
Funder
Knowledge Foundation
Available from: 2017-01-06 Created: 2017-01-06 Last updated: 2020-01-14Bibliographically approved
Afzal, Z., Lindskog, S. & Lidén, A. (2015). A Multipath TCP Proxy. In: : . Paper presented at The 11th Swedish National Computer Networking Workshop (SNCNW), Karlstad, Sweden, May 28–29, 2015.
Open this publication in new window or tab >>A Multipath TCP Proxy
2015 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Multipath TCP (MPTCP) is an extension to traditionalTCP that enables a number of performance advantages,which were not offered before. While the protocol specificationis close to being finalized, there still remain some concernsregarding deployability and security. This paper describes theon going work to develop a solution that will facilitate thedeployment of MPTCP. The solution will not only allow non-MPTCP capable end-hosts to benefit from MPTCP performancegains, but also help ease the network security concerns that manymiddleboxes face due to the possibility of data stream beingfragmented across multiple subflows.

National Category
Computer Sciences
Identifiers
urn:nbn:se:kau:diva-39059 (URN)
Conference
The 11th Swedish National Computer Networking Workshop (SNCNW), Karlstad, Sweden, May 28–29, 2015
Projects
HITS, 4707
Funder
Knowledge Foundation
Available from: 2016-01-18 Created: 2016-01-18 Last updated: 2019-11-11Bibliographically approved
Afzal, Z. & Lindskog, S. (2015). Automated Testing of IDS Rules. In: Software Testing, Verification and Validation Workshops (ICSTW), 2015 IEEE Eighth International Conference on: . Paper presented at 6th International Workshop on Security Testing (SECTEST) - IEEE Eighth International Conference on Software Testing, Verification and Validation Workshops (ICSTW), 13-17 April 2015, Graz. IEEE
Open this publication in new window or tab >>Automated Testing of IDS Rules
2015 (English)In: Software Testing, Verification and Validation Workshops (ICSTW), 2015 IEEE Eighth International Conference on, IEEE, 2015Conference paper, Published paper (Refereed)
Abstract [en]

As technology becomes ubiquitous, new vulnerabilities are being discovered at a rapid rate. Security experts continuously find ways to detect attempts to exploit those vulnerabilities. The outcome is an extremely large and complex rule set used by Intrusion Detection Systems (IDSs) to detect and prevent the vulnerabilities. The rule sets have become so large that it seems infeasible to verify their precision or identify overlapping rules. This work proposes a methodology consisting of a set of tools that will make rule management easier.

Place, publisher, year, edition, pages
IEEE, 2015
National Category
Computer Sciences
Research subject
Computer Science
Identifiers
urn:nbn:se:kau:diva-38996 (URN)10.1109/ICSTW.2015.7107461 (DOI)000373338600057 ()978-1-4799-1885-0 (ISBN)
Conference
6th International Workshop on Security Testing (SECTEST) - IEEE Eighth International Conference on Software Testing, Verification and Validation Workshops (ICSTW), 13-17 April 2015, Graz
Projects
HITS, 4707
Funder
Knowledge Foundation
Available from: 2016-01-11 Created: 2016-01-11 Last updated: 2019-11-11Bibliographically approved
Afzal, Z. & Lindskog, S. (2015). Multipath TCP IDS Evasion and Mitigation. In: Javier Lopez & Chris J. Mitchell (Ed.), Information Security: 18th International Conference, ISC 2015, Trondheim, Norway, September 9-11, 2015, Proceedings. Paper presented at The 18th Information Security Conference (ISC), Trondheim, Norway, September 9-11, 2015. (pp. 265-282). Springer, 9290
Open this publication in new window or tab >>Multipath TCP IDS Evasion and Mitigation
2015 (English)In: Information Security: 18th International Conference, ISC 2015, Trondheim, Norway, September 9-11, 2015, Proceedings / [ed] Javier Lopez & Chris J. Mitchell, Springer, 2015, Vol. 9290, p. 265-282Conference paper, Published paper (Refereed)
Abstract [en]

The existing network security infrastructure is not ready for future protocols such as Multipath TCP (MPTCP). The outcome is that middleboxes are configured to block such protocols. This paper studies the security risk that arises if future protocols are used over unaware infrastructures. In particular, the practicality and severity of cross-path fragmentation attacks utilizing MPTCP against the signature-matching capability of the Snort intrusion detection system (IDS) is investigated. Results reveal that the attack is realistic and opens the possibility to evade any signature-based IDS. To mitigate the attack, a solution is also proposed in the form of the MPTCP Linker tool. The work outlines the importance of MPTCP support in future network security middleboxes.

Place, publisher, year, edition, pages
Springer, 2015
Series
Lecture Notes in Computer Science, ISSN 0302-9743 ; 9290
National Category
Computer Sciences
Research subject
Computer Science
Identifiers
urn:nbn:se:kau:diva-39058 (URN)10.1007/978-3-319-23318-5_15 (DOI)000363678700015 ()978-3-319-23317-8 (ISBN)
Conference
The 18th Information Security Conference (ISC), Trondheim, Norway, September 9-11, 2015.
Projects
HITS, 4707
Funder
Knowledge Foundation
Available from: 2016-01-18 Created: 2016-01-18 Last updated: 2020-01-14Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9886-6651

Search in DiVA

Show all publications