CND Practice Question: Incident Detection Response And Threat Prediction
A CND analyst is configuring Snort IDS to detect a specific payload pattern within HTTP traffic where an attacker attempts to exploit a directory traversal vulnerability using the string '../'. Which Snort rule header and option configuration correctly detects this pattern within the URI component of HTTP requests?
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
✓
alert tcp any any -> $HOME_NET 80 (msg:"Directory Traversal Attempt"; content:"../"; http_uri; sid:100001; rev:1;)
To inspect HTTP URIs specifically, Snort provides the 'uricontent' or modern 'http_uri' modifier within rule options. The rule must use tcp protocol, specify external/any networks targeting internal web servers, and use the 'http_uri' sticky buffer or modifier to inspect the URI payload for '../'.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
pass tcp $EXTERNAL_NET any -> $HOME_NET 443 (msg:"Traversal"; content:"../"; http_client_body; sid:100001; rev:1;)
Why it's wrong here
HTTPS traffic on port 443 is encrypted, preventing Snort from inspecting HTTP URIs without SSL/TLS decryption, and http_client_body targets POST bodies rather than URIs.
- ✓
alert tcp any any -> $HOME_NET 80 (msg:"Directory Traversal Attempt"; content:"../"; http_uri; sid:100001; rev:1;)
Why this is correct
This rule correctly targets HTTP traffic on port 80, applies the http_uri modifier to the content match for '../', and includes a unique SID.
- ✗
alert ip any any -> any any (msg:"Directory Traversal"; uricontent:"../"; sid:100001; rev:1;)
Why it's wrong here
Using raw IP protocol without specifying TCP and failing to restrict scope to web traffic causes excessive false positives.
- ✗
log udp any any -> $HOME_NET 80 (msg:"Directory Traversal"; content:"../"; depth:2; sid:100001; rev:1;)
Why it's wrong here
HTTP traffic operates over TCP, not UDP. Furthermore, depth restricts byte search limits incorrectly.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official EC-Council exam blueprint
This CND 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 CND exam.