Suspicious Invoke-WebRequest Execution With DirectIP

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

Detects calls to PowerShell with Invoke-WebRequest cmdlet using direct IP access

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	`T1105` Ingress Tool Transfer

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `all of selection_img`

or:
Image|endswith: '\powershell.exe'
Image|endswith: '\powershell_ise.exe'
Image|endswith: '\pwsh.exe'
OriginalFileName: PowerShell.EXE
OriginalFileName: powershell_ise.EXE
OriginalFileName: pwsh.dll

Stage 2: `all of selection_commands`

or:
CommandLine|contains: ' irm '
CommandLine|contains: Invoke-RestMethod
CommandLine|contains: Invoke-WebRequest
CommandLine|contains: 'curl '
CommandLine|contains: 'iwr '
CommandLine|contains: 'wget '

Stage 3: `all of selection_ip`

or:
CommandLine|contains: '://1'
CommandLine|contains: '://2'
CommandLine|contains: '://3'
CommandLine|contains: '://4'
CommandLine|contains: '://5'
CommandLine|contains: '://6'
CommandLine|contains: '://7'
CommandLine|contains: '://8'
CommandLine|contains: '://9'

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	`irm` corpus 2 (sigma 2) `://1` corpus 3 (sigma 3) `://2` corpus 3 (sigma 3) `://3` corpus 3 (sigma 3) `://4` corpus 3 (sigma 3) `://5` corpus 3 (sigma 3) `://6` corpus 3 (sigma 3) `://7` corpus 3 (sigma 3) `://8` corpus 3 (sigma 3) `://9` corpus 3 (sigma 3) `Invoke-RestMethod` corpus 4 (sigma 4) `Invoke-WebRequest` corpus 6 (sigma 6) `curl` corpus 8 (sigma 8) `iwr` corpus 8 (sigma 8) `wget` corpus 7 (sigma 7)
`Image`	ends_with	`\powershell.exe` corpus 143 (sigma 143) `\powershell_ise.exe` corpus 27 (sigma 27) `\pwsh.exe` corpus 140 (sigma 140)
`OriginalFileName`	eq	`PowerShell.EXE` corpus 64 (sigma 60, splunk 4) `powershell_ise.EXE` corpus 8 (sigma 4, splunk 4) `pwsh.dll` corpus 72 (sigma 68, splunk 4)