Additional dll added to Spool Driver (Sysmon)

Group by: _time, host, process_name
Source: github.com/anvilogic-forge/armory

This use case look for an additional dll to the print drivers as seen with Print Nightmare CVE-2021-1675

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1547` Boot or Logon Autostart Execution
Privilege Escalation	`T1547` Boot or Logon Autostart Execution

References

https://github.com/cube0x0/CVE-2021-1675

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 11: FileCreate
Sysmon	Event ID 23: FileDelete (File Delete archived)

Rule body

id: '6446.7204'
title: Additional dll added to Spool Driver
description: 'This use case look for an additional dll to the print drivers as seen
  with Print Nightmare CVE-2021-1675. -- Threat Actor Association: Earth Lusca, Vice
  Society - Software Association: Black Basta, Play, Ransom Cartel'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_sysmon` ((EventCode=11 OR "<EventID>11<"
  OR "<EventID>23<" OR EventCode=23) "spoolsv.exe" "dll") | regex TargetFilename="\QC:\Windows\System32\spool\drivers\x64\E"
  | table _time, host, user, signature_id, process, process_*, parent_* | bin span=5s
  | stats values(*) as * by _time, host, process_path | where match(signature_id,
  "11") and match(signature_id, "23") '
techniques:
- persistence:boot or logon autostart execution
technique_id: 
- T1547
data_category:
- Windows Sysmon
references:
- https://github.com/cube0x0/CVE-2021-1675

Stages and Predicates

Stage 1: `search`

`get_endpoint_data` `get_endpoint_data_sysmon` ((EventCode=11 OR "<EventID>11<" OR "<EventID>23<" OR EventCode=23) "spoolsv.exe" "dll")

Stage 2: `regex`

| regex TargetFilename="\QC:\Windows\System32\spool\drivers\x64\E"

Stage 3: `table`

| table _time, host, user, signature_id, process, process_*, parent_*

Stage 4: `bucket`

| bin span=5s

Stage 5: `stats`

| stats values(*) as * by _time, host, process_path

Stage 6: `where`

| where match(signature_id, "11") and match(signature_id, "23")

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`EventCode`	eq	`11` corpus 26 (splunk 24, kusto 2) `23`	`field:"EventID" kind:eq`
`TargetFilename`	regex_match	`"\QC:\Windows\System32\spool\drivers\x64\E"`	`field:"TargetFilename" kind:regex_match`
`signature_id`	regex_match	`"11"` `"23"`	`field:"signature_id" kind:regex_match`

Search terms

These SPL tokens match against raw event text.

Stage	Term
1	`"<EventID>11<"`
1	`"<EventID>23<"`
1	`"spoolsv.exe"`
1	`"dll"`