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CS0-003 · Question #546

A security analyst runs tcpdump on the 10.203.10.22 machine and observes thousands of packets as shown below: Which of the following activities explains the tcpdump output?

The correct answer is D. Malware beaconing. Malware beaconing explains the tcpdump output as it typically involves a compromised host periodically sending small packets to a command and control (C2) server, often mimicking legitimate traffic patterns to evade detection.

Submitted by fatima_kr· Mar 6, 2026Security operations

Question

A security analyst runs tcpdump on the 10.203.10.22 machine and observes thousands of packets as shown below:

Which of the following activities explains the tcpdump output?

Exhibit

CS0-003 question #546 exhibit

Options

  • AIncoming nmap -sA scan
  • Bhping3 --udp scan over the network
  • CC2 communications leaving the network
  • DMalware beaconing

How the community answered

(51 responses)
  • A
    4% (2)
  • B
    14% (7)
  • C
    6% (3)
  • D
    76% (39)

Why each option

Malware beaconing explains the `tcpdump` output as it typically involves a compromised host periodically sending small packets to a command and control (C2) server, often mimicking legitimate traffic patterns to evade detection.

AIncoming nmap -sA scan

An incoming `nmap -sA` (ACK scan) would show many incoming packets to the 10.203.10.22 machine, typically for port scanning, not thousands of sustained outbound packets.

Bhping3 --udp scan over the network

An `hping3 --udp` scan would typically show a flood of UDP packets, likely to various ports or destinations, characteristic of a scanning tool, which is distinct from persistent C2 communication.

CC2 communications leaving the network

While C2 communications involve traffic leaving the network, malware beaconing is a more specific and common form of C2 communication characterized by periodic, low-volume activity, making it a more precise fit for the described output.

DMalware beaconingCorrect

Malware beaconing refers to the periodic, often low-volume communication sent from a compromised host to a command and control (C2) server to check for new instructions or confirm its active status. This type of traffic aligns with a compromised machine maintaining contact with its controller, which tcpdump would capture as repeated outbound connections from the internal host.

Concept tested: Network Traffic Analysis (Malware Beaconing)

Source: https://learn.microsoft.com/en-us/microsoft-365/security/defender-endpoint/detect-and-investigate-advanced-attacks#common-malicious-network-activity

Topics

#Network traffic analysis#tcpdump#Malware beaconing#C2 communication

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