Potentially Suspicious Child Process Of VsCode

Severity: medium
Author: Nasreddine Bencherchali (Nextron Systems)
Source: upstream

Detects uncommon or suspicious child processes spawning from a VsCode "code.exe" process. This could indicate an attempt of persistence via VsCode tasks or terminal profiles.

MITRE ATT&CK coverage

Tactic	Techniques
Defense Evasion	`T1202` Indirect Command Execution, `T1218` System Binary Proxy Execution

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation
Security-Auditing	4688	A new process has been created.

Stages and Predicates

Stage 1: `selection_parent`

ParentImage|endswith: '\code.exe'

Stage 2: `1 of selection_children_images`

or:
Image|endswith: '\calc.exe'
Image|endswith: '\cscript.exe'
Image|endswith: '\regsvr32.exe'
Image|endswith: '\rundll32.exe'
Image|endswith: '\wscript.exe'

Stage 3: `1 of selection_children_cli`

or:
CommandLine|contains: DownloadString
CommandLine|contains: ICM
CommandLine|contains: IEX
CommandLine|contains: Invoke-Command
CommandLine|contains: Invoke-Expressions
CommandLine|contains: cscript
CommandLine|contains: regsvr32
CommandLine|contains: rundll32
CommandLine|contains: wscript
or:
Image|endswith: '\cmd.exe'
Image|endswith: '\powershell.exe'
Image|endswith: '\pwsh.exe'

Stage 4: `1 of selection_children_paths`

or:
Image|contains: ':\Temp\'
Image|contains: ':\Users\Public\'
Image|contains: ':\Windows\Temp\'

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
`CommandLine`	match	`DownloadString` corpus 5 (sigma 5) `ICM` `IEX` `Invoke-Command` corpus 2 (sigma 2) `Invoke-Expressions` `cscript` corpus 12 (sigma 12) `regsvr32` corpus 11 (sigma 11) `rundll32` corpus 19 (sigma 19) `wscript` corpus 12 (sigma 12)
`Image`	ends_with	`\calc.exe` corpus 13 (sigma 13) `\cmd.exe` corpus 92 (sigma 92) `\cscript.exe` corpus 64 (sigma 64) `\powershell.exe` corpus 143 (sigma 143) `\pwsh.exe` corpus 140 (sigma 140) `\regsvr32.exe` corpus 57 (sigma 57) `\rundll32.exe` corpus 76 (sigma 76) `\wscript.exe` corpus 64 (sigma 64)
`Image`	match	`:\Temp\` corpus 12 (sigma 12) `:\Users\Public\` corpus 14 (sigma 14) `:\Windows\Temp\` corpus 9 (sigma 9)
`ParentImage`	ends_with	`\code.exe` corpus 2 (sigma 2)

Potentially Suspicious Child Process Of VsCode

MITRE ATT&CK coverage

Event coverage

Stages and Predicates

Stage 1: selection_parent

Stage 2: 1 of selection_children_images

Stage 3: 1 of selection_children_cli

Stage 4: 1 of selection_children_paths

Indicators

Stage 1: `selection_parent`

Stage 2: `1 of selection_children_images`

Stage 3: `1 of selection_children_cli`

Stage 4: `1 of selection_children_paths`