Windows Executable / Dangerous Extension Blocklist Regex for Java
/\.(exe|bat|cmd|com|pif|scr|vbs|vbe|js|jse|wsf|wsh|msi|ps1|psm1|psd1|lnk|hta|jar|py|sh|bash|zsh|fish|dll|sys|drv|reg|inf)$/iWhat this pattern does
This page provides a comprehensive, battle-tested regular expression for matching windows executable / dangerous extension blocklist, ported and verified for Java. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Java project — whether you're validating in a Spring Boot controller, a Jakarta EE service, or a standalone utility class.
Java Implementation
// Windows Executable / Dangerous Extension Blocklist
// ReDoS-safe | RegexVault — Dev & Systems > File Paths
import java.util.regex.Pattern;
public class WindowsExecutableDangerousExtensionBlocklistValidator {
private static final Pattern PATTERN =
Pattern.compile("\\.(exe|bat|cmd|com|pif|scr|vbs|vbe|js|jse|wsf|wsh|msi|ps1|psm1|psd1|lnk|hta|jar|py|sh|bash|zsh|fish|dll|sys|drv|reg|inf)$");
public static boolean validate(String input) {
return PATTERN.matcher(input).matches();
}
// Example
public static void main(String[] args) {
System.out.println(validate("malware.exe")); // true
}
}Test Cases
Matches (Valid) | Rejects (Invalid) |
|---|---|
malware.exe | document.pdf |
script.bat | image.png |
virus.com | spreadsheet.xlsx |
installer.msi | archive.zip |
script.ps1 | data.json |
exploit.jar | — |
When to use this pattern
This pattern is drawn from the Dev & Systems > File Paths category and carries a ReDoS-safe certification. That matters for Java developers because critical in Java applications since the JVM regex engine uses backtracking and is susceptible to ReDoS without careful pattern design. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.
Common Pitfalls
Attackers use double extensions (invoice.pdf.exe) and Unicode RLO characters to disguise executables. Normalize filenames and check only the final extension.
Technical Notes
Use as a BLOCKLIST — a MATCH means the file should be blocked or handled with elevated caution. This list is not exhaustive. Adjust based on your threat model and deployment environment.
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