Analytics BIOC Informational

Unusual weak authentication by user

A user account authenticated to a host via NTLMv1 or LM authentication for the first time in the past 30 days. This may be indicative of an NTLM downgrade attack A downgrade attack may force the client to authenticate with a weaker hash/protocol (such as NTLMv1 or even LM) instead of NTLMv2.

Module:
Identity Analytics
Data source:
XDR Agent
ATT&CK tactics: Lateral Movement (TA0008)
ATT&CK techniques: Use Alternate Authentication Material (T1550)
Attacker's goals:

The attacker attempts to gain access to the accounts.

Investigative actions:

Audit all login events with a weaker protocol and review any anomalous usage.

Test period:
N/A (single event)
Deduplication:
1 Day