IMPORTANT: No additional bug fixes or documentation updates
will be released for this version. For the latest information, see the
current release documentation.
Whitespace Padding in Process Command Line
editWhitespace Padding in Process Command Line
editIdentifies process execution events where the command line value contains a long sequence of whitespace characters or multiple occurrences of contiguous whitespace. Attackers may attempt to evade signature-based detections by padding their malicious command with unnecessary whitespace characters. These observations should be investigated for malicious behavior.
Rule type: eql
Rule indices:
- winlogbeat-*
- logs-endpoint.events.*
- logs-windows.*
Severity: medium
Risk score: 47
Runs every: 5m
Searches indices from: now-9m (Date Math format, see also Additional look-back time
)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Defense Evasion
Version: 9
Rule authors:
- Elastic
Rule license: Elastic License v2
Investigation guide
edit## Triage and analysis - Analyze the command line of the process in question for evidence of malicious code execution. - Review the ancestor and child processes spawned by the process in question for indicators of further malicious code execution. ## Config If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
Rule query
editprocess where event.type in ("start", "process_started") and process.command_line regex ".*[ ]{20,}.*" or /* this will match on 3 or more separate occurrences of 3+ contiguous whitespace characters */ process.command_line regex "([^ ]+[ ]{3,}[^ ]*){3,}.*"
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/