Suspicious DNS Query to HTML Smuggling AiTM Phishing Domain

ATT&CK techniques

Initial Access

Recon
Resource Dev
Initial Access
- T1566.001Spearphishing Attachment
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects DNS resolution of the rnsnno phishing infrastructure hosted under the .pro top-level domain that was used in an HTML smuggling adversary-in-the-middle campaign. Victims delivering credentials to these domains had their Microsoft 365 sessions relayed and stolen. Resolution of this infrastructure indicates a user has interacted with the phishing lure.

Reporting behind it

Related detections9 linkedT1566.001 — drag to rearrange

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Malicious Equation Editor Child Process Execution via process_creation

Microsoft 365 inbound suspicious email delivered to Inbox or Junk

Web Browser Opens .HTM/.HTML from Downloads Folder on Windows

Windows: Suspicious Attachment File Created in Outlook Temp Directories

Suspicious DNS Query to HTML Smuggling AiTM Phishing Domain

Pivot detection · T1566.001 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

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