Biblio

The increasing diffusion of malware endowed with steganographic techniques requires to carefully identify and evaluate a new set of threats. The creation of a covert channel to hide a communication within network traffic is one of the most relevant, as it can be used to exfiltrate information or orchestrate attacks. Even if network steganography is becoming a well-studied topic, only few works focus on IPv6 and consider real network scenarios. Therefore, this paper investigates IPv6 covert channels deployed in the wild. Also, it presents a performance evaluation of six different data hiding techniques for IPv6 including their ability to bypass some intrusion detection systems. Lastly, ideas to detect IPv6 covert channels are presented.

Currently 5G communication networks are gaining on importance among industry, academia, and governments worldwide as they are envisioned to offer wide range of high-quality services and unfaltering user experiences. However, certain security, privacy and trust challenges need to be addressed in order for the 5G networks to be widely welcomed and accepted. That is why in this paper, we take a step towards these requirements and we introduce a dedicated SDN-based integrated security framework for the Internet of Radio Light (IoRL) system that is following 5G architecture design. In particular, we present how TCP SYN-based scanning activities which typically comprise the first phase of the attack chain can be detected and mitigated using such an approach. Enclosed experimental results prove that the proposed security framework has potential to become an effective defensive solution.

Currently, due to improvements in defensive systems network covert channels are increasingly drawing attention of cybercriminals and malware developers as they can provide stealthiness of the malicious communication and thus to bypass existing security solutions. On the other hand, the utilized data hiding methods are getting increasingly sophisticated as the attackers, in order to stay under the radar, distribute the covert data among many connections, protocols, etc. That is why, the detection of such threats becomes a pressing issue. In this paper we make an initial step in this direction by presenting a data mining-based detection of such advanced threats which relies on pattern discovery technique. The obtained, initial experimental results indicate that such solution has potential and should be further investigated.

Network covert channels are currently typically seen as a security threat which can result in e.g. confidential data leakage or in a hidden data exchange between malicious parties. However, in this paper we want to investigate network covert channels from a less obvious angle i.e. we want to verify whether it is possible to use them as a green networking technique. Our observation is that usually covert channels utilize various redundant "resources" in network protocols e.g. unused/reserved fields that would have been transmitted anyway. Therefore, using such "resources" for legitimate transmissions can increase the total available bandwidth without sending more packets and thus offering potential energy savings. However, it must be noted that embedding and extracting processes related to data hiding consumes energy, too. That is why, in this paper we try to establish whether the potentially saved energy due to covert channels utilization exceeds the effort needed to establish and maintain covert data transmission. For this purpose, a proof-of-concept implementation has been created to experimentally measure the impact of network covert channels on resulting energy consumption. The obtained results show that the approach can be useful mostly under specific circumstances, i.e., when the total energy consumption of the network devices is already relatively high. Furthermore, the impact of different types of network covert channels on the energy consumption is examined to assess their usefulness from the green networking perspective.

Network covert channels enable stealthy communications for malware and data exfiltration. For this reason, the development of effective countermeasures for covert channels is important for the protection of individuals and organizations. However, due to the number of available covert channel techniques, it can be considered impractical to develop countermeasures for all existing covert channels. In recent years, researchers started to develop countermeasures that (instead of only countering one particular hiding technique) can be applied to a whole family of similar hiding techniques. These families are referred to as hiding patterns. The main contribution of this paper is that we extend the idea of hiding patterns by introducing the concept of countermeasure variation. Countermeasure variation is the slight modification of a given countermeasure that was designed to detect covert channels of one specific hiding pattern so that the countermeasure can also detect covert channels that are representing other hiding patterns. We exemplify countermeasure variation using the compressibility score originally presented by Cabuk et al. The compressibility score is used to detect covert channels of the 'inter-packet times' pattern and we show that countermeasure variation allows the application of the compressibility score to detect covert channels of the 'size modulation' pattern, too.

Even if information hiding can be used for licit purposes, it is increasingly exploited by malware to exfiltrate data or to coordinate attacks in a stealthy manner. Therefore, investigating new methods for creating covert channels is fundamental to completely assess the security of the Internet. Since the popularity of the carrier plays a major role, this paper proposes to hide data within VoIP traffic. Specifically, we exploit Voice Activity Detection (VAD), which suspends the transmission during speech pauses to reduce bandwidth requirements. To create the covert channel, our method transforms a VAD-activated VoIP stream into a non-VAD one. Then, hidden information is injected into fake RTP packets generated during silence intervals. Results indicate that steganographically modified VAD-activated VoIP streams offer a good trade-off between stealthiness and steganographic bandwidth.