Spam, Phishing and Malware


  • Bad news = You cannot be prepared to all attacker’s inventions
  • Good news = Being slightly more clever, than the attacker expects you are, is enough.
  1. Quick and automate reaction makes troubles.
  2. Do not accept what message suggests, until you are perfectly sure you understand the intentions.
  3. Do not belive the sender's identity until you really verify it (check sender’s email address closely).
  • Better safe, than sorry.
  • Be brave! Never try to conceal your possible mistake - take it in possitive way - we all learn from mistakes. We all :-)
  • Cowards who awkwardly try to avoid of mistake revealing usualy make things much worse for them and for the rest of the institution.


Good article about clicking links in emails (phishing etc.)

How and why Thunderbird block remote content

See also “Dealing with malware, spam, suspicious content” in separated CERGE-EI Wiki article (details about security measures applied to incoming emails)

and "Spam fiters at CERGE-EI" (describing chain of email filters for incoming traffic)


  • Unsolicited mail, just offers unneeded or annoying things.
  • By links to fraudulent webpages or danger attachments could be transformed to other type.
  • Do not open links and attachments, do not reply to it, delete it.


[Classification: ANNOYING]
  • By wiki: A hoax is a falsehood deliberately fabricated to masquerade as the truth.
  • You could be abused to help distribute it. Other harmful content could be appended.
  • Do not resend it to any other address, delete it.


[Classification: PRETTY DANGEROUS]
  • Asks for confidential and private information, often by using fraudulent webpage, masking the request as an account renew etc. Make time pressure and urgency illusion.
  • Never use offered links without its authenticity thorough verification.
  • Be very careful and abstemious by inserting your login and password anywhere.


[Classification: DANGEROUS]
  • The message looks like sent from a trustworthy address, your jobmate, manager, IT crowd, your home institution server etc.
  • Verify sender’s email address, not only the free text label presented by some e-mail client.
  • Take care of “mistyped” form of address, e.g cerce-ei,cz or enlarged form etc.


[Classification: DANGEROUS]
  • The harmful code hidden in an executable attachment or in a document as a macro or on the fraudulent webpage linked from the message.
  • Never open documents or pages looking like something very very interesting. There is no chance to take a non-binding look.


[Classification: THE MOST DANGEROUS]
  • Special malware encrypting every data you can access and asking ransom. The process of encrypting could be long term so backups could be affected too.
  • Avoid being infected by malware.
  1. Thing first, check all circumstances, ask in doubt (IT, colleagues, sender,…).
  2. Do not allow the time presure effect, think twice. postpone the action (back to step 1 eventually :-)
  3. Only if you are absolutely sure, continue with an action suggested in email (settings review, password change etc.)
  4. In case of any suspicion at any time, share it with IT (including all details).
  5. If you think you have compromised your password or account in any way, change the password ASAP and inform IT (compulsory).

In any doubt, do not hesitate to ask Please prepare complete documentation, timeline, addresses, raw text of message (see wiki - problem reporting)

  • /var/www/html/dokuwiki/data/pages/public/emai/spam.txt
  • Last modified: 2022-12-02 10:04
  • by vesely