Nslookup PowerShell Download Cradle - ProcessCreation

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

Detects suspicious powershell download cradle using nslookup. This cradle uses nslookup to extract payloads from DNS records

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `all of selection_img`

or:
Image|contains: '\nslookup.exe'
OriginalFileName: '\nslookup.exe'

Stage 2: `all of selection_cmd`

or:
CommandLine|contains: ' -q=txt '
CommandLine|contains: ' -querytype=txt '
or:
ParentImage|endswith: '\powershell.exe'
ParentImage|endswith: '\pwsh.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	`-q=txt` `-querytype=txt`
`Image`	match	`\nslookup.exe`
`OriginalFileName`	eq	`\nslookup.exe`
`ParentImage`	ends_with	`\powershell.exe` corpus 16 (sigma 16) `\pwsh.exe` corpus 16 (sigma 16)