Possible CVE-2023-23397 Outlook Forced Authentication via Outbound SMB (via network_connection)
- Product
- windows
- Category
- network_connection
- Author
- HuntRule
- Published
- 2026-07-06
- Updated
- 2026-08-28
ATT&CK techniques
Cred AccessRecon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule detects a Windows host initiating an outbound SMB connection on TCP 445 to a non-private external address. CVE-2023-23397 abuses a Microsoft Outlook reminder property carrying a UNC path to coerce the host into leaking Net-NTLMv2 credentials to an attacker-controlled SMB server. Successful forced authentication lets adversaries relay or crack the hash so the residual leak of a domain credential must be triaged.
Reporting behind it
- intel471.comhttps://www.intel471.com/blog/detecting-cve-2023-23397-how-to-identify-exploitation-of-the-latest-microsoft-outlook-vulnerability
- attack.mitre.orghttps://attack.mitre.org/techniques/T1187/
- proofpoint.comhttps://www.proofpoint.com/us/blog/threat-insight/ta577s-unusual-attack-chain-leads-ntlm-data-theft
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