Local Network Connection Initiated By Script Interpreter

Severity: medium
Author: frack113
Source: upstream

Detects a script interpreter (Wscript/Cscript) initiating a local network connection to download or execute a script hosted on a shared folder.

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	`T1105` Ingress Tool Transfer

Event coverage

Provider	Event ID	Title
Sysmon	3	Network connection

Stages and Predicates

Stage 1: `selection`

or:
DestinationIp|cidr: '10.0.0.0/8'
DestinationIp|cidr: '127.0.0.0/8'
DestinationIp|cidr: '169.254.0.0/16'
DestinationIp|cidr: '172.16.0.0/12'
DestinationIp|cidr: '192.168.0.0/16'
DestinationIp|cidr: '::1/128'
DestinationIp|cidr: 'fc00::/7'
DestinationIp|cidr: 'fe80::/10'
or:
Image|endswith: '\cscript.exe'
Image|endswith: '\wscript.exe'
Initiated: true

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
`DestinationIp`	cidr_match	`10.0.0.0/8` corpus 12 (sigma 12) `127.0.0.0/8` corpus 13 (sigma 13) `169.254.0.0/16` corpus 12 (sigma 12) `172.16.0.0/12` corpus 12 (sigma 12) `192.168.0.0/16` corpus 12 (sigma 12) `::1/128` corpus 13 (sigma 13) `fc00::/7` corpus 12 (sigma 12) `fe80::/10` corpus 12 (sigma 12)
`Image`	ends_with	`\cscript.exe` corpus 64 (sigma 64) `\wscript.exe` corpus 64 (sigma 64)
`Initiated`	eq	`true` corpus 40 (sigma 40)

Neighbors

Broader alternatives (more inclusive than this rule)

These rules match a superset of what this rule catches. They cover the same events plus more. Use them if you want wider coverage and can absorb more false positives.

Outbound Network Connection Initiated By Script Interpreter [sigma] (drops 1 filter this rule applies) (first-stage match only; downstream stages may differ)