LanmanServer MaxMpxCt Registry Modification for Lateral Movement Preparation

ATT&CK techniques

Persistence → Lateral Movement

Recon
Resource Dev
Initial Access
Execution
Persistence
- T1112Modify Registry
Priv Esc
Defense Evasion
- T1112Modify Registry
Cred Access
Discovery
Lateral Movement
- T1570Lateral Tool Transfer
Collection
C2
Exfiltration
Impact

What it detects

This rule detects modification of the LanmanServer MaxMpxCt registry value, which raises the maximum outstanding SMB requests to support high-volume lateral spreading. Huntress observed BlackCat affiliates tuning this value before mass deployment across a network. This uncommon server parameter change is a preparation step for scaled lateral movement and ransomware distribution.

Reporting behind it

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LanmanServer MaxMpxCt Registry Modification for Lateral Movement Preparation

Pivot detection · T1112 · 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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