Suspicious Advpack Call Via Rundll32.EXE

Severity: high
Author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
Source: upstream

Detects execution of "rundll32" calling "advpack.dll" with potential obfuscated ordinal calls in order to leverage the "RegisterOCX" function

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `all of selection_img`

or:
CommandLine|contains: rundll32
Image|endswith: '\rundll32.exe'
OriginalFileName: RUNDLL32.EXE

Stage 2: `all of selection_cli_dll`

CommandLine|contains: advpack

Stage 3: `all of selection_cli_ordinal`

or:
CommandLine|contains: '#+'
CommandLine|contains: 12
CommandLine|contains: '#-'

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	`#+` corpus 3 (sigma 3) `#-` corpus 3 (sigma 3) `12` `advpack` `rundll32` corpus 19 (sigma 19)
`Image`	ends_with	`\rundll32.exe` corpus 76 (sigma 76)
`OriginalFileName`	eq	`RUNDLL32.EXE` corpus 28 (sigma 25, splunk 3)