Now we Discuss some internal and advanced scanning Methods..
First of Which is OS Fingerprinting…
What is OS Fingerprinting ??
OS fingerprinting is the method to determine the operating system that is running on the target system.
The two different types of fingerprinting are:
• Active stack fingerprinting
• Passive fingerprinting
Active Stack FingerPrinting:
Based on the fact that OS vendors implement the TCP stack differently.Specially crafted packets are sent to remote OSs and response is noted. The responses are then compared with a database to determine the OS.
Passive banner grabbing refers to indirectly scanning a system to reveal its server’s operating system.
It is also based on the differential implantation of the stack and the various ways an OS responds to it.
It uses sniffing techniques instead of the scanning techniques. It is less accurate than active fingerprinting.
TOOL USED FOR OS FINGERPRINTING :p0f Os Fingerprinting Tool
- machines that connect to your box (SYN mode),
- machines you connect to (SYN+ACK mode),
- machine you cannot connect to (RST+ mode),
- machines whose communications you can observe.
- firewall presence, NAT use (useful for policy enforcement),
- existence of a load balancer setup,
- the distance to the remote system and its uptime,
- other guy’s network hookup (DSL, OC3, avian carriers) and his ISP.