Marian Gawron

Hierarchical object log format for normalisation of security events

The differences in log file formats employed in a variety of services and applications remain to be a problem for security analysts and developers of intrusion detection systems. The proposed solution, i.e. the usage of common log formats, has a limited utilization within existing solutions for security management. In our paper, we reveal the reasons for this limitation. We show disadvantages of existing common log formats for normalisation of security events. To deal with it we have created a new log format that fits for intrusion detection purposes and can be extended easily. Taking previous work into account, we would like to propose a new format as an extension to existing common log formats, rather than a standalone specification.

Evaluation of in‐memory storage engine for machine learning analysis of security events

Modern security information and event management systems should be capable to store and process high amount of events or log messages in different formats and from different sources. This requirement often prevents such systems from usage of computational heavy algorithms for security analysis. To deal with this issue, we built our system based on an in‐memory database with an integrated machine learning library, namely, SAP HANA. Three approaches, that is, (1) deep normalisation of log messages, (2) storing data in the main memory and (3) running data analysis directly in the database, allow us to increase processing speed in such a way that machine learning analysis of security events becomes possible nearly in real time. Besides that, we developed a universal anomaly detection algorithm, which uses vector space model to represent and cluster textual log messages. Together with deep normalisation approach, this algorithm solves the problem of correlation for heterogenous security events containing many text fields. To prove our concepts, we measured the processing speed for the developed system on the data generated using Active Directory testbed, compared it with classical system architecture based on PostgreSQL database and showed the efficiency of our approach for high‐speed analysis of security events. Copyright

High-Speed Security Analytics Powered by In-Memory Machine Learning Engine

Modern Security Information and Event Management systems should be capable to store and process high amount of events or log messages in different formats and from different sources. This requirement often prevents such systems from usage of computational-heavy algorithms for security analysis. To deal with this issue, we built our system based on an in-memory data base with an integrated machine learning library, namely SAP HANA. Three approaches, i.e. (1) deep normalisation of log messages (2) storing data in the main memory and (3) running data analysis directly in the database, allow us to increase processing speed in such a way, that machine learning analysis of security events becomes possible nearly in real-time. To prove our concepts, we measured the processing speed for the developed system on the data generated using Active Directory tested and showed the efficiency of our approach for high-speed analysis of security events.

Automatic detection of vulnerabilities for advanced security analytics

The detection of vulnerabilities in computer systems and computer networks as well as the weakness analysis are crucial problems. The presented method tackles the problem with an automated detection. For identifying vulnerabilities the approach uses a logical representation of preconditions and postconditions of vulnerabilities. The conditional structure simulates requirements and impacts of each vulnerability. Thus an automated analytical function could detect security leaks on a target system based on this logical format. With this method it is possible to scan a system without much expertise, since the automated or computer-aided vulnerability detection does not require special knowledge about the target system. The gathered information is used to provide security advisories and enhanced diagnostics which could also detect attacks that exploit multiple vulnerabilities of the system.

Poisson-Based Anomaly Detection for Identifying Malicious User Behaviour

Nowadays, malicious user behaviour that does not trigger access violation or alert of data leak is difficult to be detected. Using the stolen login credentials the intruder doing espionage will first try to stay undetected: silently collect data from the company network and use only resources he is authorised to access. To deal with such cases, a Poisson-based anomaly detection algorithm is proposed in this paper. Two extra measures make it possible to achieve high detection rates and meanwhile reduce number of false positive alerts: 1 checking probability first for the group, and then for single users and 2 selecting threshold automatically. To prove the proposed approach, we developed a special simulation testbed that emulates user behaviour in the virtual network environment. The proof-of-concept implementation has been integrated into our prototype of a SIEM system -- Real-time Event Analysis and Monitoring System, where the emulated Active Directory logs from Microsoft Windows domain are extracted and normalised into Object Log Format for further processing and anomaly detection. The experimental results show that our algorithm was able to detect all events related to malicious activity and produced zero false positive results. Forethought as the module for our self-developed SIEM system based on the SAP HANA in-memory database, our solution is capable of processing high volumes of data and shows high efficiency on experimental dataset.

Leveraging Event Structure for Adaptive Machine Learning on Big Data Landscapes

Modern machine learning techniques have been applied to many aspects of network analytics in order to discover patterns that can clarify or better demonstrate the behavior of users and systems within a given network. Often the information to be processed has to be converted to a different type in order for machine learning algorithms to be able to process them. To accurately process the information generated by systems within a network, the true intention and meaning behind the information must be observed. In this paper we propose different approaches for mapping network information such as IP addresses to integer values that attempts to keep the relation present in the original format of the information intact. With one exception, all of the proposed mappings result in at most 64 bit long outputs in order to allow atomic operations using CPUs with 64 bit registers. The mapping output size is restricted in the interest of performance. Additionally we demonstrate the benefits of the new mappings for one specific machine learning algorithm k-means and compare the algorithms results for datasets with and without the proposed transformations.

Automatic vulnerability detection for weakness visualization and advisory creation

The detection of vulnerabilities in computer systems and computer networks as well as the representation of the results are crucial problems. The presented method tackles the problem with an automated detection and an intuitive representation. For detecting vulnerabilities the approach uses a logical representation of preconditions and postconditions of vulnerabilities. Thus an automated analytical function could detect security leaks on a target system. The gathered information is used to provide security advisories and enhanced diagnostics for the system. Additionally the conditional structure allows us to create attack graphs to visualize the network structure and the integrated vulnerability information. Finally we propose methods to resolve the identified weaknesses whether to remove or update vulnerable applications and secure the target system. This advisories are created automatically and provide possible solutions for the security risks.

CGA integration into IPsec/IKEv2 authentication

In IPv6 networks, two security mechanisms are available at the network-layer; SEcure Neighbor Discovery (SEND) and IP security (IPsec). Although both provide authentication, neither subsumes the other; both SEND and IPsec mechanisms should be deployed together to protect IPv6 networks. However, when a node uses both SEND and IPsec, the authentication has to be done twice, which increases the burden on the node and decreases its performance. In this paper, we propose an approach to enable them to work together under the mediation of an Authentication Management Block, where IPsec uses the public-private keys obtained by SEND rather than negotiating its own authentication credentials in order to save the time and facilitate the IPsec authentication deployment. We implement and evaluate our approach using ipsec-tools and DoCoMo SEND implementations. Our proof-of-concept experiment shows a considerable speedup of IPsec authentication time.

Automatic Vulnerability Classification Using Machine Learning

The classification of vulnerabilities is a fundamental step to derive formal attributes that allow a deeper analysis. Therefore, it is required that this classification has to be performed timely and accurate. Since the current situation demands a manual interaction in the classification process, the timely processing becomes a serious issue. Thus, we propose an automated alternative to the manual classification, because the amount of identified vulnerabilities per day cannot be processed manually anymore. We implemented two different approaches that are able to automatically classify vulnerabilities based on the vulnerability description. We evaluated our approaches, which use Neural Networks and the Naive Bayes methods respectively, on the base of publicly known vulnerabilities.

PVD: Passive vulnerability detection

The identification of vulnerabilities relies on detailed information about the target infrastructure. The gathering of the necessary information is a crucial step that requires an intensive scanning or mature expertise and knowledge about the system even though the information was already available in a different context. In this paper we propose a new method to detect vulnerabilities that reuses the existing information and eliminates the necessity of a comprehensive scan of the target system. Since our approach is able to identify vulnerabilities without the additional effort of a scan, we are able to increase the overall performance of the detection. Because of the reuse and the removal of the active testing procedures, our approach could be classified as a passive vulnerability detection. We will explain the approach and illustrate the additional possibility to increase the security awareness of users. Therefore, we applied the approach on an experimental setup and extracted security relevant information from web logs.