Suspicious Parent Double Extension File Execution

Severity: high
Author: frack113, Nasreddine Bencherchali (Nextron Systems)
Source: upstream

Detect execution of suspicious double extension files in ParentCommandLine

MITRE ATT&CK coverage

Tactic	Techniques
Defense Evasion	`T1036.007` Masquerading: Double File Extension

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `selection`

or:
ParentCommandLine|contains: .doc.js
ParentCommandLine|contains: .doc.lnk
ParentCommandLine|contains: .docx.js
ParentCommandLine|contains: .docx.lnk
ParentCommandLine|contains: .pdf.js
ParentCommandLine|contains: .pdf.lnk
ParentCommandLine|contains: .ppt.js
ParentCommandLine|contains: .ppt.lnk
ParentCommandLine|contains: .pptx.js
ParentCommandLine|contains: .pptx.lnk
ParentCommandLine|contains: .rtf.js
ParentCommandLine|contains: .rtf.lnk
ParentCommandLine|contains: .txt.js
ParentCommandLine|contains: .txt.lnk
ParentCommandLine|contains: .xls.js
ParentCommandLine|contains: .xls.lnk
ParentCommandLine|contains: .xlsx.js
ParentCommandLine|contains: .xlsx.lnk
ParentImage|endswith: .doc.js
ParentImage|endswith: .doc.lnk
ParentImage|endswith: .docx.js
ParentImage|endswith: .docx.lnk
ParentImage|endswith: .pdf.js
ParentImage|endswith: .pdf.lnk
ParentImage|endswith: .ppt.js
ParentImage|endswith: .ppt.lnk
ParentImage|endswith: .pptx.js
ParentImage|endswith: .pptx.lnk
ParentImage|endswith: .rtf.js
ParentImage|endswith: .rtf.lnk
ParentImage|endswith: .txt.js
ParentImage|endswith: .txt.lnk
ParentImage|endswith: .xls.js
ParentImage|endswith: .xls.lnk
ParentImage|endswith: .xlsx.js
ParentImage|endswith: .xlsx.lnk

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.