The reader is referred here to an earlier article for the basics of sniffer detection. When sniffers are working on switches, the chances of detecting them are higher. In such a scenario the sniffer is not a passive device; it performs certain activities by which it can be detected.
ARP spoofing can be detected using a program called ARP Watch. It is used to monitor the ARP cache of a machine to see if there is duplication. If there is, it could trigger alarms and lead to detection of sniffers. It can be obtained at online.securityfocus.com/data/tools/arpwatch.tar.Z
As is clear from the above sections, one method of sniffing in a switched environment is using ARP spoofing, and the machine that will most probably be ARP spoofed is the gateway. One thing that can be done is to add the MAC address of the gateway permanently to your ARP cache. This can be done by giving the -s flag to the arp command. Read more about this on the arp man page. Alternatively, you could use the /etc/ethers file for placing the MAC addresses of the important machines to prevent spoofing of those machines.
Final words of advice: Use encryption. Switch to SSH and SCP instead of Telnet and FTP.
Sumit Dhar works for SLMsoft.com.
|Android Candy: Intercoms||Apr 23, 2015|
|"No Reboot" Kernel Patching - And Why You Should Care||Apr 22, 2015|
|Return of the Mac||Apr 20, 2015|
|DevOps: Better Than the Sum of Its Parts||Apr 20, 2015|
|Play for Me, Jarvis||Apr 16, 2015|
|Drupageddon: SQL Injection, Database Abstraction and Hundreds of Thousands of Web Sites||Apr 15, 2015|
- Tips for Optimizing Linux Memory Usage
- "No Reboot" Kernel Patching - And Why You Should Care
- DevOps: Better Than the Sum of Its Parts
- Return of the Mac
- Android Candy: Intercoms
- Drupageddon: SQL Injection, Database Abstraction and Hundreds of Thousands of Web Sites
- Designing Foils with XFLR5
- Non-Linux FOSS: .NET?
- Play for Me, Jarvis