Detects inbound messages carrying PDF attachments that embed banner images designed to imitate Adobe Sign branding. The rule targets attachments with file_type 'pdf' and traverses embedded content within the attachment (file.explode), applying a YARA rule named 'adobe_sign_lure_banner_images' to identify lure images or assets. When a match is found, it flags a Credential Phishing scenario involving brand impersonation via PDFs. Detection relies on file analysis and YARA scanning to catch deceptive documents before user interaction.