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EC-Council

312-50V11 · Question #868

Henry Is a cyber security specialist hired by BlackEye - Cyber security solutions. He was tasked with discovering the operating system (OS) of a host. He used the Unkornscan tool to discover the OS…

The correct answer is B. 128. Default TTL values in IP packets are OS-specific and can be used as a passive OS fingerprinting technique. Windows systems use a default TTL of 128, making it identifiable during network scanning.

Scanning Networks

Question

Henry Is a cyber security specialist hired by BlackEye - Cyber security solutions. He was tasked with discovering the operating system (OS) of a host. He used the Unkornscan tool to discover the OS of the target system. As a result, he obtained a TTL value, which Indicates that the target system is running a Windows OS. Identify the TTL value Henry obtained, which indicates that the target OS is Windows.

Options

  • A64
  • B128
  • C255
  • D138

How the community answered

(53 responses)
  • A
    2% (1)
  • B
    92% (49)
  • C
    2% (1)
  • D
    4% (2)

Why each option

Default TTL values in IP packets are OS-specific and can be used as a passive OS fingerprinting technique. Windows systems use a default TTL of 128, making it identifiable during network scanning.

A64

A TTL of 64 is the default for Linux and Unix-based systems, not Windows.

B128Correct

Windows operating systems initialize IP packets with a default TTL of 128. When a scanning tool like Unicornscan receives a response with a TTL at or near 128, it infers the target is running a Windows OS. This passive fingerprinting technique works because each OS vendor sets a distinct starting TTL value in their network stack.

C255

A TTL of 255 is typically associated with network infrastructure devices such as Cisco routers or Solaris systems.

D138

138 is not a standard or recognized default TTL value assigned by any major operating system vendor.

Concept tested: Passive OS fingerprinting via IP TTL values

Source: https://learn.microsoft.com/en-us/troubleshoot/windows-server/networking/default-ttl-value-for-operating-systems

Topics

#OS fingerprinting#TTL values#Windows identification#passive fingerprinting

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