Spam wave with encrypted ZIP files attached
Since 2 days a wave of spam has been observed in Freiburg schools and PH (Freiburg University of Education). The BelWü (the data network of the scientific institutions of the state of Baden-Württemberg/"Baden-Württemberg extended LAN") is about to implement defense measures.
The mails usually look legitimate and contain an encrypted ZIP archive in the attachment, and the password is built into the mail text. Sometimes complete mail texts from large round mails are used, which were stolen from compromised single accounts. Senders of the mails are hacked accounts from all over the world.
The German Federal Office for Information Security gives valuable advice on general mail security in the following article: