CHFI Mobile and Malware Forensics Practice Question
A security analyst observes a suspicious process creating multiple mutexes with names like 'XxX_12345' and 'XxX_67890' and making outbound connections to an IP address 185.130.5.1 on port 443. Which behavioral indicator is MOST consistent with malware communication?
⚠ Common exam trap
The CHFI exam often tests the misconception that any outbound connection on port 443 is automatically legitimate HTTPS traffic, but the trap here is that malware frequently uses this port for C2, and the mutex pattern is a key differentiator from benign software.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The mutexes indicate an attempt to prevent multiple instances, and outbound connections suggest C2 activity
The creation of mutexes with a consistent naming pattern (e.g., 'XxX_12345') is a classic anti-replication mechanism used by malware to ensure only one instance runs on a system, preventing conflicts and detection. The outbound connections to a specific IP on port 443 (HTTPS) are highly indicative of command-and-control (C2) communication, as malware often uses encrypted channels to blend in with legitimate traffic. Option C correctly identifies both the mutex's purpose (preventing multiple instances) and the network behavior (C2 activity), making it the most consistent with malware communication.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The process is performing data exfiltration via DNS tunneling
Why it's wrong here
DNS tunneling exfiltration would manifest as a stream of DNS queries encoding stolen data in subdomain labels or TXT records, sent to and from a resolver on UDP/TCP 53. The alert here describes direct outbound connections to a single IP on 443, with no DNS query artifacts, so the traffic pattern matches HTTPS-based command-and-control rather than DNS tunneling.
- ✗
The process is attempting to spread to other machines via SMB
Why it's wrong here
SMB-based lateral movement requires sessions on TCP 445 (or 139) with SMB negotiation, named-pipe access, and often the use of administrative shares or exploit payloads such as EternalBlue; none of that appears in the observation. The only network activity cited is outbound communication to 185.130.5.1 on 443, which is unrelated to SMB propagation and suggests a C2 channel.
- ✓
The mutexes indicate an attempt to prevent multiple instances, and outbound connections suggest C2 activity
Why this is correct
Malware commonly creates specific named mutexes to ensure only one instance runs, preventing duplicate infections and making analysis harder; the presence of these mutexes is a behavioral indicator. Multiple outbound TLS connections to a fixed external IP on 443 are a classic command-and-control pattern, especially when the IP is a known suspicious address like 185.130.5.1, so combined these observations point to C2 activity.
- ✗
The process is a legitimate application using mutexes for inter-process communication
Why it's wrong here
Although legitimate applications can use mutexes for inter-process synchronization, the mutex names observed, combined with an outbound connection to a suspicious non-standard external IP on 443, are not consistent with normal application behavior. A benign process would have a recognized binary, known publisher, and documented network endpoints; this process exhibits neither, making the legitimate-app explanation unsupported.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CHFI practice question is part of Courseiva's free EC-Council certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CHFI exam.