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Potential Remote Credential Access via Registry

Elastic Stack Serverless Security

Identifies remote access to the registry to potentially dump credential data from the Security Account Manager (SAM) registry hive in preparation for credential access and privileges elevation.

Rule type: eql

Rule indices:

  • winlogbeat-*
  • logs-system.*
  • logs-endpoint.events.*

Severity: high

Risk score: 73

Runs every: 5m

Searches indices from: now-9m (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Lateral Movement
  • Credential Access
  • has_guide

Version: 101

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

Dumping registry hives is a common way to access credential information. Some hives store credential material,
such as the SAM hive, which stores locally cached credentials (SAM secrets), and the SECURITY hive, which stores domain
cached credentials (LSA secrets). Dumping these hives in combination with the SYSTEM hive enables the attacker to
decrypt these secrets.

Attackers can use tools like secretsdump.py or CrackMapExec to dump the registry hives remotely, and use dumped
credentials to access other systems in the domain.

  • Identify the specifics of the involved assets, such as their role, criticality, and associated users.
  • Identify the user account that performed the action and whether it should perform this kind of action.
  • Determine the privileges of the compromised accounts.
  • Investigate other alerts associated with the user/source host during the past 48 hours.
  • Investigate potentially compromised accounts. Analysts can do this by searching for login events (e.g., 4624) to the target
    host.
  • This activity is unlikely to happen legitimately. Any activity that triggered the alert and is not inherently malicious
    must be monitored by the security team.
  • Credential Acquisition via Registry Hive Dumping - a7e7bfa3-088e-4f13-b29e-3986e0e756b8
  • Initiate the incident response process based on the outcome of the triage.
  • Isolate the involved hosts 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.
  • Determine if other hosts were compromised.
  • Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and
    malware components.
  • Reimage the host operating system or restore the compromised files to clean versions.
  • Ensure that the machine has the latest security updates and is not running unsupported Windows versions.
  • 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).

Rule query

sequence by host.id, user.id with maxspan=1m
 [authentication where
   event.outcome == "success" and event.action == "logged-in" and
   winlog.logon.type == "Network" and not user.name == "ANONYMOUS LOGON" and
   not user.domain == "NT AUTHORITY" and source.ip != "127.0.0.1" and source.ip !="::1"]
 [file where event.action == "creation" and process.name : "svchost.exe" and
  file.Ext.header_bytes : "72656766*" and user.id : "S-1-5-21-*" and file.size >= 30000 and
  not file.path :
           ("?:\\Windows\\system32\\HKEY_LOCAL_MACHINE_SOFTWARE_Microsoft_*.registry",
            "?:\\Users\\*\\AppData\\Local\\Microsoft\\Windows\\UsrClass.dat.LOG?",
            "?:\\Users\\*\\AppData\\Local\\Microsoft\\Windows\\UsrClass.dat",
            "?:\\Users\\*\\ntuser.dat.LOG?",
            "?:\\Users\\*\\NTUSER.DAT")]

Framework: MITRE ATT&CKTM