HackTool - Jlaive In-Memory Assembly Execution

Severity: medium
Author: Jose Luis Sanchez Martinez (@Joseliyo_Jstnk)
Source: upstream

Detects the use of Jlaive to execute assemblies in a copied PowerShell

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059.003` Command and Scripting Interpreter: Windows Command Shell

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `parent_selection`

ParentCommandLine|endswith: .bat
ParentImage|endswith: '\cmd.exe'

Stage 2: `1 of selection1`

CommandLine|contains: .bat.exe
CommandLine|contains: powershell.exe
Image|endswith: '\xcopy.exe'

Stage 3: `1 of selection2`

CommandLine|contains: .bat.exe
CommandLine|contains: pwsh.exe
Image|endswith: '\xcopy.exe'

Stage 4: `1 of selection3`

CommandLine|contains: '+h'
CommandLine|contains: '+s'
CommandLine|contains: .bat.exe
Image|endswith: '\attrib.exe'

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	`+h` `+s` `.bat.exe` `powershell.exe` corpus 2 (sigma 2) `pwsh.exe` corpus 2 (sigma 2)
`Image`	ends_with	`\attrib.exe` corpus 3 (sigma 3) `\xcopy.exe` corpus 5 (sigma 5)
`ParentCommandLine`	ends_with	`.bat`
`ParentImage`	ends_with	`\cmd.exe` corpus 13 (sigma 13)

HackTool - Jlaive In-Memory Assembly Execution

MITRE ATT&CK coverage

Event coverage

Stages and Predicates

Stage 1: parent_selection

Stage 2: 1 of selection1

Stage 3: 1 of selection2

Stage 4: 1 of selection3

Indicators

Stage 1: `parent_selection`

Stage 2: `1 of selection1`

Stage 3: `1 of selection2`

Stage 4: `1 of selection3`