312-50V10 · Question #158
A penetration tester is conducting a port scan on a specific host. The tester found several ports opened that were confusing in concluding the Operating System (OS) version installed. Considering the
The correct answer is B. The host is likely a printer.. The simultaneous presence of ports 515 (LPD), 631 (IPP), and 9100 (RAW/JetDirect) are all printing-specific protocols, making a network printer the most likely identification. No general-purpose OS or router would expose all three of these ports by default.
Question
A penetration tester is conducting a port scan on a specific host. The tester found several ports opened that were confusing in concluding the Operating System (OS) version installed. Considering the NMAP result below, which of the following is likely to be installed on the target machine by the OS? Starting NMAP 5.21 at 2011-03-15 11:06 NMAP scan report for 172.16.40.65 Host is up (1.00s latency). Not shown: 993 closed ports PORT STATE SERVICE 21/tcp open ftp 23/tcp open telnet 80/tcp open http 139/tcp open netbios-ssn 515/tcp open 631/tcp open ipp 9100/tcp open MAC Address: 00:00:48:0D:EE:89
Options
- AThe host is likely a Linux machine.
- BThe host is likely a printer.
- CThe host is likely a router.
- DThe host is likely a Windows machine.
How the community answered
(18 responses)- A6% (1)
- B83% (15)
- D11% (2)
Why each option
The simultaneous presence of ports 515 (LPD), 631 (IPP), and 9100 (RAW/JetDirect) are all printing-specific protocols, making a network printer the most likely identification. No general-purpose OS or router would expose all three of these ports by default.
While a Linux system can run print services like CUPS on port 631, the combination of ports 515, 631, and 9100 together is the embedded device fingerprint of a hardware network printer, not a general-purpose Linux host.
Ports 515 (Line Printer Daemon), 631 (Internet Printing Protocol), and 9100 (RAW/JetDirect) are the three standard network printing ports used by embedded printer hardware from vendors like HP, Canon, and Epson. The simultaneous presence of all three printing-specific ports - especially 9100 which is the HP JetDirect signature port - is a definitive device fingerprint for a network printer. No standard OS installation or router would natively expose all three of these ports without a dedicated embedded print engine.
Routers expose management and routing protocol ports but would not natively open ports 515, 631, and 9100 simultaneously, as those are specific to embedded print engine hardware.
A Windows machine may run the Windows Print Spooler but does not natively open ports 515, 631, and 9100 simultaneously by default - this specific three-port combination identifies embedded printer hardware.
Concept tested: OS and device fingerprinting via open port analysis
Source: https://nmap.org/book/osdetect.html
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