Shell Process Spawned by Java.EXE

Status: test
Severity: medium
Log source: category process_creation, product windows
Author: Andreas Hunkeler (@Karneades), Nasreddine Bencherchali
Source: github.com/SigmaHQ/sigma

Detects shell spawned from Java host process, which could be a sign of exploitation (e.g. log4j exploitation)

Known false positives

Legitimate calls to system binaries
Company specific internal usage

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	No specific technique
Persistence	No specific technique
Privilege Escalation	No specific technique

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation
Security-Auditing	Event ID 4688: A new process has been created.

Rule body

title: Shell Process Spawned by Java.EXE
id: dff1e1cc-d3fd-47c8-bfc2-aeb878a754c0
related:
    - id: 0d34ed8b-1c12-4ff2-828c-16fc860b766d
      type: similar
status: test
description: Detects shell spawned from Java host process, which could be a sign of exploitation (e.g. log4j exploitation)
references:
    - https://web.archive.org/web/20231230220738/https://www.lunasec.io/docs/blog/log4j-zero-day/
author: Andreas Hunkeler (@Karneades), Nasreddine Bencherchali
date: 2021-12-17
modified: 2024-01-18
tags:
    - attack.initial-access
    - attack.persistence
    - attack.privilege-escalation
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\java.exe'
        Image|endswith:
            - '\bash.exe'
            - '\cmd.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
    filter_main_build:
        ParentImage|contains: 'build'  # excluding CI build agents
        CommandLine|contains: 'build'  # excluding CI build agents
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Legitimate calls to system binaries
    - Company specific internal usage
level: medium

Stages and Predicates

Stage 0: `condition`

selection and not 1 of filter_main_*

Stage 1: `selection`

selection:
    ParentImage|endswith: '\java.exe'
    Image|endswith:
        - '\bash.exe'
        - '\cmd.exe'
        - '\powershell.exe'
        - '\pwsh.exe'

Stage 2: `not filter_main_build`

filter_main_build:
    ParentImage|contains: 'build'
    CommandLine|contains: 'build'

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`CommandLine`	match	`build`	`excludes:CommandLine` `field:"CommandLine" value:"build"`
`ParentImage`	match	`build`	`excludes:ParentImage` `field:"ParentImage" value:"build"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Image`	ends_with	`\bash.exe` corpus 21 (sigma 21) `\cmd.exe` corpus 130 (sigma 130) `\powershell.exe` corpus 179 (sigma 178, kusto 1) `\pwsh.exe` corpus 165 (sigma 164, kusto 1)	`field:"Image" kind:ends_with`
`ParentImage`	ends_with	`\java.exe` corpus 8 (sigma 8)	`field:"ParentImage" kind:ends_with value:"\java.exe"`