blat

Blat is a Windows 32- and 64-bit command-line email utility that sends a message-body file through SMTP (and can post to Usenet through NNTP). It is a legitimate dual-use mailer. Kaspersky documented Librarian Ghouls using Blat to send staged victim data through an attacker-controlled SMTP server, making the utility relevant to authorized SMTP-exfiltration emulation and incident analysis. Blat requires access to a mail server; its presence or use alone does not establish malicious activity.