A framework for DNS based detection and mitigation of malware infections on a network
- Authors: Stalmans, Etienne , Irwin, Barry V W
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429827 , vital:72642 , 10.1109/ISSA.2011.6027531
- Description: Modern botnet trends have lead to the use of IP and domain fast-fluxing to avoid detection and increase resilience. These techniques bypass traditional detection systems such as blacklists and intrusion detection systems. The Domain Name Service (DNS) is one of the most prevalent protocols on modern networks and is essential for the correct operation of many network activities, including botnet activity. For this reason DNS forms the ideal candidate for monitoring, detecting and mit-igating botnet activity. In this paper a system placed at the network edge is developed with the capability to detect fast-flux domains using DNS queries. Multiple domain features were examined to determine which would be most effective in the classification of domains. This is achieved using a C5.0 decision tree classifier and Bayesian statistics, with positive samples being labeled as potentially malicious and nega-tive samples as legitimate domains. The system detects malicious do-main names with a high degree of accuracy, minimising the need for blacklists. Statistical methods, namely Naive Bayesian, Bayesian, Total Variation distance and Probability distribution are applied to detect mali-cious domain names. The detection techniques are tested against sample traffic and it is shown that malicious traffic can be detected with low false positive rates.
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An evaluation of lightweight classification methods for identifying malicious URLs
- Authors: Egan, Shaun P , Irwin, Barry V W
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429839 , vital:72644 , 10.1109/ISSA.2011.6027532
- Description: Recent research has shown that it is possible to identify malicious URLs through lexical analysis of their URL structures alone. This paper intends to explore the effectiveness of these lightweight classification algorithms when working with large real world datasets including lists of malicious URLs obtained from Phishtank as well as largely filtered be-nign URLs obtained from proxy traffic logs. Lightweight algorithms are defined as methods by which URLs are analysed that do not use exter-nal sources of information such as WHOIS lookups, blacklist lookups and content analysis. These parameters include URL length, number of delimiters as well as the number of traversals through the directory structure and are used throughout much of the research in the para-digm of lightweight classification. Methods which include external sources of information are often called fully featured classifications and have been shown to be only slightly more effective than a purely lexical analysis when considering both false-positives and false-negatives. This distinction allows these algorithms to be run client side without the introduction of additional latency, but still providing a high level of accu-racy through the use of modern techniques in training classifiers. Anal-ysis of this type will also be useful in an incident response analysis where large numbers of URLs need to be filtered for potentially mali-cious URLs as an initial step in information gathering as well as end us-er implementations such as browser extensions which could help pro-tect the user from following potentially malicious links. Both AROW and CW classifier update methods will be used as prototype implementa-tions and their effectiveness will be compared to fully featured analysis results. These methods are interesting because they are able to train on any labelled data, including instances in which their prediction is cor-rect, allowing them to build a confidence in specific lexical features. This makes it possible for them to be trained using noisy input data, making them ideal for real world applications such as link filtering and information gathering.
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