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„Chain Phishing“ on Office 365 accounts

Cybercriminals are constantly evolving their attack strategies, and one particularly dangerous method is so-called "Chain Phishing" - a devious attack technique specifically targeting Office 365 accounts. But what exactly is behind it, and how can you protect yourself?

What is Chain Phishing?

In Chain Phishing, attackers first take over a compromised email account to send seemingly legitimate phishing emails to existing contacts. These messages often include deceptively real responses to previous conversations or seemingly authentic attachments and links. This lowers the recipients’ suspicion, as the emails appear to come from a trusted source.

How does the attack work?

Initial infection

An Office 365 account is compromised through stolen credentials or malware infection.

Realistic phishing emails

Attackers send manipulated emails as replies to previous conversations.

Spread of the attack

Recipients open attachments or click on links, making them victims themselves.

Further compromise

The attack continues in a chain reaction.

Why is Chain Phishing so dangerous?

Exploitation of trust

Since the attacks originate from real accounts, security measures and user vigilance are bypassed.

Deceptively real content

By accessing previous email threads, the messages appear highly credible.

Self-propagating attack

The attack spreads automatically as more accounts get compromised.

Data loss & business disruption

Compromised accounts can be used not only for fraud but also for encrypting or deleting critical business data.

How can you protect yourself?

Enable Multi-Factor Authentication (MFA)

Significantly increases security by making unauthorized access much more difficult.

Raise security awareness

Regularly educate employees on phishing risks.

Use advanced email security solutions

Threat detection systems can help identify and stop suspicious activities.

Never reuse passwords

Strong, unique passwords are essential.

Report suspicious emails to IT

It’s better to be overly cautious than to fall victim to an attack.

Use a professional backup solution

An external backup is crucial to protect against data loss caused by compromised or encrypted emails. Office 365 does not offer a true backup solution, so implementing an independent backup strategy is essential.

Chain Phishing poses a serious threat to Office 365 users, as attackers exploit trust through already compromised accounts. However, with the right security measures, the risk can be significantly minimized. Most importantly, a professional backup solution can prevent data loss in critical situations and ensure business continuity.

Stay vigilant – and don’t blindly click on emails that seem familiar!