sigma-rules/rules/windows/credential_access_mimikatz_powershell_module.toml

[metadata]
creation_date = "2020/12/07"
maturity = "development"
updated_date = "2022/05/09"

[rule]
author = ["Elastic"]
description = """
Mimikatz is a credential dumper capable of obtaining plaintext Windows account logins and passwords, along with many
other features that make it useful for testing the security of networks. This rule detects the Invoke-Mimikatz
PowerShell command.
"""
from = "now-9m"
index = ["logs-endpoint.events.*", "winlogbeat-*", "logs-windows.*"]
language = "eql"
license = "Elastic License v2"
name = "Mimikatz Powershell Module Activity"
note = """## Triage and analysis

### Investigating Mimikatz PowerShell Activity

[Mimikatz](https://github.com/gentilkiwi/mimikatz) is an open-source tool used to collect, decrypt, and/or use cached
credentials. This tool is commonly abused by adversaries during the post-compromise stage where adversaries have gained
an initial foothold on an endpoint and are looking to elevate privileges and seek out additional authentication objects
such as tokens/hashes/credentials that can then be used to move laterally and pivot across a network.

This specific rule is based on Mimikatz command-line parameters used to dump credentials from the Local Security
Authority Subsystem Service (LSASS). Any activity triggered from this rule should be treated with high priority as it
typically represents an active adversary.

More information about Mimikatz components and how to detect/prevent them can be found on [ADSecurity](https://adsecurity.org/?page_id=1821).

#### Possible investigation steps

- Investigate the process execution chain (parent process tree) for unknown processes. Examine their executable files
for prevalence, whether they are located in expected locations, and if they are signed with valid digital signatures.
- Contact the account owner and confirm whether they are aware of this activity.
- Examine PowerShell (script block logging), Windows and endpoint detection and response (EDR) logs to understand what
was executed in the host.
- Investigate other alerts associated with the user/host during the past 48 hours.
- Use process name, command line, and file hash to search for occurrences on other hosts.
- Investigate potentially compromised accounts. Analysts can do this by searching for login events (for example, 4624) to the
target host.
  - Examine network and security events in the environment to identify potential lateral movement using compromised credentials.

### False positive analysis

- This activity is unlikely to happen legitimately. Benign true positives (B-TPs) can be added as exceptions if necessary.

### Related rules

- Mimikatz Memssp Log File Detected - ebb200e8-adf0-43f8-a0bb-4ee5b5d852c6
- Creation or Modification of Domain Backup DPAPI private key - b83a7e96-2eb3-4edf-8346-427b6858d3bd
- Modification of WDigest Security Provider - d703a5af-d5b0-43bd-8ddb-7a5d500b7da5

### Response and remediation

- Initiate the incident response process based on the outcome of the triage.
- Isolate the involved host to prevent further post-compromise behavior.
- Investigate credential exposure on systems compromised or used by the attacker to ensure all compromised accounts are
identified. Reset passwords for these accounts and other potentially compromised credentials, such as email, business
systems, and web services.
- Validate that cleartext passwords are disabled in memory for use with `WDigest`.
- Look into preventing access to `LSASS` using capabilities such as LSA protection or antivirus/EDR tools that provide
this capability.
- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and
malware components.
- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
- Using the incident response data, update logging and audit policies to improve the mean time to detect (MTTD) and the
mean time to respond (MTTR).

## Config

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
"""
references = ["https://attack.mitre.org/software/S0002/"]
risk_score = 99
rule_id = "ac96ceb8-4399-4191-af1d-4feeac1f1f46"
severity = "critical"
tags = ["Elastic", "Host", "Windows", "Threat Detection", "Credential Access"]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where event.type in ("start", "process_started") and process.name : ("cmd.exe", "powershell.exe", "pwsh.exe")
and process.args : ("*DumpCreds", "*Mimikatz*")
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1003"
name = "OS Credential Dumping"
reference = "https://attack.mitre.org/techniques/T1003/"
[[rule.threat.technique.subtechnique]]
id = "T1003.001"
name = "LSASS Memory"
reference = "https://attack.mitre.org/techniques/T1003/001/"



[rule.threat.tactic]
id = "TA0006"
name = "Credential Access"
reference = "https://attack.mitre.org/tactics/TA0006/"