Browser Execution In Headless Mode

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

Detects execution of Chromium based browser in headless mode

MITRE ATT&CK coverage

Tactic	Techniques
Defense Evasion	`T1564.003` Hide Artifacts: Hidden Window
Command & Control	`T1105` Ingress Tool Transfer

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`

or:
Image|endswith: '\brave.exe'
Image|endswith: '\chrome.exe'
Image|endswith: '\msedge.exe'
Image|endswith: '\opera.exe'
Image|endswith: '\vivaldi.exe'
CommandLine|contains: --headless

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	`--headless` corpus 5 (sigma 5)
`Image`	ends_with	`\brave.exe` corpus 20 (sigma 20) `\chrome.exe` corpus 11 (sigma 11) `\msedge.exe` corpus 22 (sigma 22) `\opera.exe` corpus 21 (sigma 21) `\vivaldi.exe` corpus 19 (sigma 19)

Neighbors

Stricter alternatives (narrower than this rule)

The rules below may be useful if you find the current rule is too noisy / lacks specificity.

File Download with Headless Browser [sigma] (adds 2 filters) (first-stage match only; downstream stages may differ)

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.

Chromium Browser Headless Execution To Mockbin Like Site [sigma] (drops 1 filter this rule applies) (first-stage match only; downstream stages may differ)
File Download From Browser Process Via Inline URL [sigma] (drops 1 filter this rule applies) (first-stage match only; downstream stages may differ)