Detection rules › Splunk
comsvcs.dll Lsass Memory Dump (Sysmon)
Credential dumping within the lsass memory using Windows built-in comsvcs.dll file. When System32 crashes this DLL contains a function called minidumpw which dumps the lsass memory. This does not require additional tools like Mimikatz and Procdump in order to perform the lsass dump
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Credential Access | T1003.001 OS Credential Dumping: LSASS Memory |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
Rule body yaml
id: '5463.5687'
title: ' comsvcs.dll Lsass Memory Dump'
description: 'Credential dumping within the lsass memory using Windows built-in comsvcs.dll
file. When System32 crashes this DLL contains a function called minidumpw which
dumps the lsass memory. This does not require additional tools like Mimikatz and
Procdump in order to perform the lsass dump. -- Threat Actor Association: APT27,
APT35/Phosphorus/Magic Hound, BlackCat, Lancefly, Lazarus, Volt Typhoon, Witchetty,
Wizard Spider - Software Association: Akira, Conti, HermeticWiper/Trojan.Killdisk,
Prestige, PYSA/Mespinoza, Vice Society - Atomics T1003 Test #3 Atomics T1003.001
Test #3'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_sysmon` EventCode=1 ("rundll32.exe"
OR "rundll32") ("comsvcs.dll" OR "comsvcs") ("dmp" OR "MiniDump" OR "DumpProc" OR
"lsass.exe" OR "lsass" OR "#24") | table _time, host, user signature_id, user, process_id,
process_name, process_path, process, parent_process_id, parent_process_name, parent_process_path,
parent_process | bin span=1s | stats values(*) as * by _time, host, process '
techniques:
- credential-access:os credential dumping:lsass memory
technique_id:
- T1003.001
data_category:
- Windows Sysmon
references:
- https://en.hackndo.com/remote-lsass-dump-passwords/#manual-method--procdump
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_sysmon` EventCode=1 ("rundll32.exe" OR "rundll32") ("comsvcs.dll" OR "comsvcs") ("dmp" OR "MiniDump" OR "DumpProc" OR "lsass.exe" OR "lsass" OR "#24")
Stage 2: table
| table _time, host, user signature_id, user, process_id, process_name, process_path, process, parent_process_id, parent_process_name, parent_process_path, parent_process
Stage 3: bucket
| bin span=1s
Stage 4: stats
| stats values(*) as * by _time, host, process
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 |
|---|---|---|
EventCode | eq |
|
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 | "rundll32.exe" |
| 1 | "rundll32" |
| 1 | "comsvcs.dll" |
| 1 | "comsvcs" |
| 1 | "dmp" |
| 1 | "MiniDump" |
| 1 | "DumpProc" |
| 1 | "lsass.exe" |
| 1 | "lsass" |
| 1 | "#24" |