200-201 Security Monitoring Practice Question
An analyst finds a YARA rule that matches a file containing the string 'MZ' at offset 0 and includes 'CreateRemoteThread'. This rule likely identifies:
⚠ Common exam trap
The trap is that 'MZ' and 'CreateRemoteThread' are individually generic — candidates may overthink and pick a benign file type, but the exam expects recognition that MZ + Windows injection API = malicious Windows PE, not a document or Linux binary.
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
✓
A malicious executable
The YARA rule matches a file starting with the 'MZ' magic bytes at offset 0 and containing the string 'CreateRemoteThread', which together identify a Windows Portable Executable (PE) that performs process injection. 'MZ' is the DOS header signature of every Windows executable, and CreateRemoteThread is a Windows API commonly used for DLL injection and process hollowing. This combination strongly indicates a malicious executable.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A benign PDF
Why it's wrong here
PDF files begin with the '%PDF' magic bytes, not 'MZ' at offset 0, and CreateRemoteThread is a Windows API import absent from benign document structure. A rule for a benign PDF would match PDF-specific objects, streams and metadata rather than executable headers.
- ✗
A network packet capture
Why it's wrong here
'MZ' at offset 0 is the DOS/PE executable header, so the rule targets a Windows binary, not captured network traffic; YARA scans files and memory, not packet streams. Packet capture analysis would instead use protocol dissectors or BPF filters on a pcap.
- ✓
A malicious executable
Why this is correct
The 'MZ' signature at offset 0 confirms a Windows PE executable, while 'CreateRemoteThread' indicates process injection capability. Together these satisfy the stem's detection criteria for a malicious executable, since legitimate binaries rarely combine a valid PE header with remote thread creation for code injection.
- ✗
A Linux ELF binary
Why it's wrong here
Linux ELF binaries start with the 0x7F 'ELF' magic number, not 'MZ', and CreateRemoteThread is a Windows API with no ELF equivalent. A YARA rule identifying ELF files would key on the ELF header and Linux-specific symbols or sections.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 200-201 practice question is part of Courseiva's free Cisco 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 200-201 exam.