Detection rules › Sigma
Unsigned or Unencrypted SMB Connection to Share Established
Detects SMB server connections to shares without signing or encryption enabled. This could indicate potential lateral movement activity using unsecured SMB shares.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Lateral Movement | T1021.002 Remote Services: SMB/Windows Admin Shares |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| SMBServer | 4000 |
Stages and Predicates
Stage 1: all of selection_shares
or:
ShareName|contains: 'ADMIN$'
ShareName|contains: 'C$'
ShareName|contains: 'IPC$'
Stage 2: all of selection_status
or:
EncyptionUsed: false
SigningUsed: false
Stage 3: not 1 of filter_main_local_ips
or:
ClientAddress|cidr: '127.0.0.0/8'
ClientAddress|cidr: '169.254.0.0/16'
ClientAddress|cidr: '::1/128'
ClientAddress|cidr: 'fc00::/7'
ClientAddress|cidr: 'fe80::/10'
ClientAddress|contains: 00000000000000000000000000000001
ClientAddress|contains: '0200????7F'
ClientAddress|contains: '0200????A9FE'
ClientAddress|contains: FC00000000000000
ClientAddress|contains: FE80000000000000
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
ClientAddress | cidr_match |
|
ClientAddress | match |
|
EncyptionUsed | eq |
|
ShareName | match |
|
SigningUsed | eq |
|