Author:
Hamza Rahmani
Affiliation:
College of Telecommunications, The University of Tunisia, Tunisia
Abstract:
Among various types of attacks on an Ethernet network, “sniffing attack” is probably one of the most difficult attacks to handle. Sniffers are programs that allow a host to capture any packets in an Ethernet network, by putting the host’s Network Interface Card (NIC) into the promiscuous mode. When a host’s NIC is in the normal mode, it captures only the packets sent to the host. Since many basic services, such as FTP, Telnet and SMTP, send passwords and data in clear text in the packets, sniffers can be used by hackers to capture passwords and confidential data.
A number of anti-sniffers have been developed, such as PMD [18], PromiScan [17] and L0pht AntiSniff [19]. An anti-sniffer is a program that tries to detect the hosts running sniffers, in a Local Area Network (LAN).
Current anti-sniffers are mainly based on three detection techniques, namely: the ARP detection, the DNS detection, and the RTT (Round Trip Time) detection techniques [13 and 16]. However, sniffers are becoming
very advanced so that anti-sniffers are unable to detect them. The main drawback of these detection techniques is that they rely on the ARP, ICMP and/or DNS reply messages generated by the sniffing hosts. Therefore, in order to stay undetectable by anti-sniffers, advanced sniffers do not generate such reply messages while sniffing.
This paper discusses an anti-sniffer based on a new detection technique. The technique uses mainly ARP cache poisoning attack to detect sniffing hosts in an Ethernet network. The technique is implemented in a tool, called SupCom anti-sniffer, which automatically gives system administrator a better helping hand regarding the detection of sniffers. Four anti-sniffers, PMD [18], PromiScan [17], L0pht AntiSniff [19] and SupCom anti-sniffer, are tested and the evaluation results show that SupCom anti-sniffer succeeded to detect more sniffing hosts than the other
anti-sniffers.
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