Embedded malware has been discovered in a popular PDF reader application and is currently being exploited in the wild. Because the supply chain was compromised, this malware is present in versions 10.0 through 10.3 of the software's official versions. The malware is not present in version 10.4.
Since the details around this malware are still emerging, the Chief Information Security Officer has asked the senior security analyst to collaborate with the IT asset inventory manager to find instances of the installed software in order to begin response activities. The asset inventory manager has asked an analyst to provide a regular expression that will identify the affected versions. The software installation entries are formatted as follows:
Reader 10.0
Reader 10.1
Reader 10.2
Reader 10.3
Reader 10.4
Which of the following regular expression entries will accurately identify all the affected versions?
Correct Answer: C
Comprehensive and Detailed Step-by-Step Explanation:
Understand the Question Requirements:The goal is to use a regular expression (regex) to match software versions 10.0 through 10.3, but exclude version 10.4.
Review Regex Syntax:
[ ] indicates a character set (matches any one character in the set).
[0-3] matches any digit between 0 and 3.
\. escapes the period (.) so it matches a literal period instead of acting as a wildcard.
( ) groups parts of the regex together.
Analyze Each Option:
Option A: Reader(*)[1][0].[0-4:
Incorrect. The use of (*) is not valid syntax in this context and [0-4 is incomplete or misformatted.
Option B: Reader[11[01X.f0-3'
Incorrect. This is an invalid regex syntax, mixing character sets and mismatched brackets.
Option C: Reader( )[1][0].[0-3:
Correct. This regex is valid and matches "Reader 10.0", "Reader 10.1", "Reader 10.2", and "Reader 10.3" while excluding "Reader 10.4".
Breakdown:
Reader: Matches the text "Reader".
[1][0]: Matches "10" as a combination of two characters.
\.: Matches the literal period.
[0-3]: Matches any single digit between 0 and 3.
Option D: Reader( )[1][0] X.[1-3:
Incorrect. The syntax X.[1-3 is invalid, and this does not match the required versions.
Conclusion:The regex in Option C correctly identifies all affected versions (10.0, 10.1, 10.2, 10.3) while excluding the unaffected version (10.4).
References:
CompTIA Advanced Security Practitioner (CASP+) Study Guide, Chapter on Vulnerability Management.
CompTIA CASP+ Exam Objectives: "Analyze risks associated with new vulnerabilities." Regular Expressions Documentation from CASP+ Official Reference Materials.
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