Usage of homograph characters detected in an email

Synopsis

Field	Value
Activation Period	14 Days
Training Period	30 Days
Test Period	N/A (single event)
Deduplication Period	1 Hour 30 Minutes
Required Data	Microsoft 365 Emails
Detection Modules	Email
Detector Tags	Evasion
ATT&CK Tactic	Stealth (TA0005)
ATT&CK Technique	Social Engineering: Impersonation (T1684.001), Masquerading (T1036)
Severity	Informational

Description

Detected characters resembling Latin letters within an email's subject and/or body. This could indicate an attempt to impersonate a well-known brand or impersonate someone's identity. This could also be used as a method to evade text scanners and analyzers.

Attacker's Goals

Impersonate known legitimate brands or evade defenses, tricking recipients into clicking on malicious links or attachments.

Investigative actions

• Check the characters in the email address for any characters that might look slightly different.
• Examine the sender's IP address and reputation.
• Verify whether the sender's IP address has appeared in different log sources before, and if it is recognizable.
• Check the domain the email came from, and if this domain is recognized within the organization.
• If the message contains attachments or links, scrutinize them for any suspicious indications.
• Monitor further actions taken, such as file downloads or access to potentially malicious links.