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200-201 Practice Question: An analyst sees an alert: 'ET POLICY Outgoing…
An analyst sees an alert: 'ET POLICY Outgoing HTTP Request with Suspicious User-Agent (Mozilla/5.0 compatible; MSIE 6.0; Windows NT 5.1)'. The source is an internal host that typically uses Windows 10. What should the analyst suspect?
⚠ Common exam trap
Cisco often tests the concept that an anomalous User-Agent string inconsistent with the host's known OS is a red flag for malware, not an indication of the actual OS version.
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 traffic is likely generated by malware
The User-Agent string 'Mozilla/5.0 compatible; MSIE 6.0; Windows NT 5.1' mimics Internet Explorer 6 on Windows XP (NT 5.1). Since the source host normally runs Windows 10, this outdated and mismatched User-Agent is a strong indicator of malware attempting to disguise its traffic as legacy browser activity to evade detection.
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 traffic is from a web proxy
Why it's wrong here
A web proxy would rewrite or strip the User-Agent, not emit an obsolete MSIE 6.0 string from a Windows 10 host. The mismatch between the claimed Windows NT 5.1 platform and the actual Windows 10 endpoint indicates spoofed or malware-generated traffic. Proxies are checked when investigating egress filtering or content inspection, not User-Agent anomalies.
- ✗
The host is running Windows XP
Why it's wrong here
The host is known to run Windows 10, so a Windows NT 5.1 User-Agent cannot reflect the real OS; it is spoofed by malware or a scripted tool. Windows XP would be the conclusion only if asset data confirmed that OS, which the stem explicitly contradicts. The anomaly is the forged header, not the endpoint's platform.
- ✗
The host is running a browser update
Why it's wrong here
A Windows 10 host reporting an MSIE 6.0 user-agent indicates spoofed or hardcoded client software, suggesting malware or unauthorised tooling rather than a browser update. It is tempting because outdated user-agents often accompany patching, but genuine Windows 10 browsers never present Internet Explorer 6 identifiers.
- ✓
The traffic is likely generated by malware
Why this is correct
The legacy MSIE 6.0 user-agent on Windows NT 5.1 (XP) contradicts the host's expected Windows 10 baseline, so the string is spoofed rather than genuine. Malware commonly hard-codes outdated user-agents for HTTP command-and-control or payload retrieval, making this anomalous egress consistent with infection.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.