---
type: source
title: "Threats Posed by Emails"
tags: [email-security, phishing, malware, university-guidelines]
related: [e-mail-sicherheit, phishing-prevention]
created: 2026-06-30
updated: 2026-06-30
sources: ["output/rz_uni_greifswald_de_dienste_allgemein_e_mail_e_mail_sicherheit_bedrohung_durch_.md"]
---

# Threats Posed by Emails

This source provides security guidelines and behavioral recommendations from the **Universitätsrechenzentrum (URZ)** to protect users of the **Universität Greifswald** from malicious emails, phishing, and malware.

## Core Security Principles
- **Trust Model:** Unsigned emails are considered untrustworthy. The URZ uses digital signatures (via [[dfn-pki-zertifikate]]) to verify the identity of its staff.
- **Institutional Policy:** The University and the URZ will **never** request the disclosure or confirmation of login credentials via email.
- **Software Maintenance:** Users are urged to keep all software and browser plugins updated to mitigate vulnerabilities.

## Threat Landscape
- **Phishing:** Targeted attacks designed to steal credentials. The source emphasizes that phishing is distinct from mass-spam and often bypasses standard spam filters.
- **Ransomware:** Malware that encrypts local hard drive data and demands payment for decryption.
- **Social Engineering:** The use of personalized emails based on publicly available contact data to deceive recipients.
- **Macro-based Malware:** Malicious code embedded in Office documents that executes when macros are enabled.

## Detection and Mitigation
The URZ provides a checklist for identifying malicious emails and specific behavioral rules to prevent infection.

### Detection Checklist
1. Cryptic character combinations in the email address.
2. Mismatch between the sender's name and the actual email address.
3. Significant errors in spelling and phrasing.
4. Greetings or closings that deviate from standard communication patterns.
5. File attachments with double extensions (e.g., `.pdf.exe`).
6. Requests to enter data on external websites.

### Behavioral Recommendations
- **Immediate Action:** Delete suspicious messages immediately; do not click links or download attachments.
- **Attachment Safety:** Be skeptical of `.exe`, `.msi`, and `.bat` files. Use isolated viewers (e.g., online Office viewers) for Office documents to prevent macro execution.
- **Data Protection:** Use the **URZ central file servers** ([[home-directory]]) for data storage, as they provide automatic snapshots and backups for rapid recovery from ransomware.
- **Verification:** If a known sender sends a suspicious email, verify the content with them via a different communication channel.

## External References
The guidelines cite the following for further information:
- **BSI** (Federal Office for Information Security) regarding spam and phishing.
- **Heise** regarding sender spoofing.
- **G DATA** regarding malware reading Outlook address books.