Detection rules › Splunk
Additional dll added to Spool Driver (Windows Event Log)
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
Event coverage
| Provider | Event | Title |
|---|---|---|
| PrintService | Event ID 316 | Printer driver param1 for param2 param3 was added or updated. |
Rule body yaml
id: '6446.7203'
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_winevent` (TERM(EventCode=316) OR "<EventID>316<")
TERM(Printer) TERM(driver) TERM(added) TERM(updated) | rex field=_raw max_match=0
"(?i)(?<driver>\S+.dll)"| eval c_driver=mvcount(driver) | table _time, host, user,
signature_id, process, process_*, parent_*, signature, c_driver | bin span=1s |
stats values(*) as * by _time, host | where c_driver > 2 '
techniques:
- persistence:boot or logon autostart execution
technique_id:
- T1547
data_category:
- Windows event logs
references:
- https://github.com/cube0x0/CVE-2021-1675
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=316) OR "<EventID>316<") TERM(Printer) TERM(driver) TERM(added) TERM(updated)
Stage 2: rex
| rex field=_raw max_match=0 "(?i)(?<driver>\S+.dll)"
Stage 3: eval
| eval c_driver=mvcount(driver)
Stage 4: table
| table _time, host, user, signature_id, process, process_*, parent_*, signature, c_driver
Stage 5: bucket
| bin span=1s
Stage 6: stats
| stats values(*) as * by _time, host
Stage 7: where
| where c_driver > 2
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.
Search terms
Bare-string tokens in the SPL search body. Splunk matches each token against _raw (the untyped raw event text) anywhere it appears, not against a specific field. These don't surface in the Indicators table because they aren't predicates on a known field.
| Stage | Term |
|---|---|
| 1 | TERM |
| 1 | "<EventID>316<" |
| 1 | TERM |
| 1 | Printer |
| 1 | TERM |
| 1 | driver |
| 1 | TERM |
| 1 | added |
| 1 | TERM |
| 1 | updated |