Regex Editor & Tester

Detects malicious attachment header tricks in emails: matches 'filename=' where the name appears to be a document or image (hwp, pdf, jpg, png) via a double-extension trick, followed by 5+ spaces used to push the true executable extension (.scr, .exe, .com, .bat) out of view. Case-insensitive flag catches FILENAME=, .EXE, etc. Useful for spam/malware filtering and phishing detection, especially Korean-targeted campaigns (hwp).