Symbolic Link to Shadow Copy Created

  1[metadata]
  2creation_date = "2021/12/25"
  3integration = ["endpoint", "windows", "system", "m365_defender", "sentinel_one_cloud_funnel", "crowdstrike"]
  4maturity = "production"
  5updated_date = "2026/05/04"
  6
  7[rule]
  8author = ["Elastic", "Austin Songer"]
  9description = """
 10Identifies the creation of symbolic links to a shadow copy. Symbolic links can be used to access files in the shadow
 11copy, including sensitive files such as ntds.dit, System Boot Key and browser offline credentials.
 12"""
 13false_positives = ["Legitimate administrative activity related to shadow copies."]
 14from = "now-9m"
 15index = [
 16    "endgame-*",
 17    "logs-crowdstrike.fdr*",
 18    "logs-endpoint.events.process-*",
 19    "logs-m365_defender.event-*",
 20    "logs-sentinel_one_cloud_funnel.*",
 21    "logs-system.security*",
 22    "logs-windows.forwarded*",
 23    "logs-windows.sysmon_operational-*",
 24    "winlogbeat-*",
 25]
 26language = "eql"
 27license = "Elastic License v2"
 28name = "Symbolic Link to Shadow Copy Created"
 29note = """## Triage and analysis
 30
 31### Investigating Symbolic Link to Shadow Copy Created
 32
 33Shadow copies are backups or snapshots of an endpoint's files or volumes while they are in use. Adversaries may attempt to discover and create symbolic links to these shadow copies in order to copy sensitive information offline. If Active Directory (AD) is in use, often the ntds.dit file is a target as it contains password hashes, but an offline copy is needed to extract these hashes and potentially conduct lateral movement.
 34
 35#### Possible investigation steps
 36
 37- Identify the user account that performed the action and whether it should perform this kind of action.
 38- 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.
 39- Investigate other alerts associated with the user/host during the past 48 hours.
 40- Determine if a volume shadow copy was recently created on this endpoint.
 41- Review privileges of the end user as this requires administrative access.
 42- Verify if the ntds.dit file was successfully copied and determine its copy destination.
 43- Investigate for registry SYSTEM file copies made recently or saved via Reg.exe.
 44- Investigate recent deletions of volume shadow copies.
 45- Identify other files potentially copied from volume shadow copy paths directly.
 46
 47### False positive analysis
 48
 49- This rule should cause very few false positives. Benign true positives (B-TPs) can be added as exceptions if necessary.
 50
 51### Related rules
 52
 53- NTDS or SAM Database File Copied - 3bc6deaa-fbd4-433a-ae21-3e892f95624f
 54
 55### Response and remediation
 56
 57- Initiate the incident response process based on the outcome of the triage.
 58- 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.
 59- If the entire domain or the `krbtgt` user was compromised:
 60  - Activate your incident response plan for total Active Directory compromise which should include, but not be limited to, a password reset (twice) of the `krbtgt` user.
 61- Locate and remove static files copied from volume shadow copies.
 62- Command-Line tool mklink should require administrative access by default unless in developer mode.
 63- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components.
 64- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
 65- 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).
 66"""
 67references = [
 68    "https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/mklink",
 69    "https://2017.zeronights.org/wp-content/uploads/materials/ZN17_Kheirkhabarov_Hunting_for_Credentials_Dumping_in_Windows_Environment.pdf",
 70    "https://blog.netwrix.com/2021/11/30/extracting-password-hashes-from-the-ntds-dit-file/",
 71    "https://www.hackingarticles.in/credential-dumping-ntds-dit/",
 72]
 73risk_score = 47
 74rule_id = "d117cbb4-7d56-41b4-b999-bdf8c25648a0"
 75setup = """## Setup
 76
 77This rule is designed for data generated by [Elastic Defend](https://www.elastic.co/security/endpoint-security), which provides native endpoint detection and response, along with event enrichments designed to work with our detection rules.
 78
 79Setup instructions: https://ela.st/install-elastic-defend
 80
 81### Additional data sources
 82
 83This rule also supports the following third-party data sources. For setup instructions, refer to the links below:
 84
 85- [CrowdStrike](https://ela.st/crowdstrike-integration)
 86- [Microsoft Defender XDR](https://ela.st/m365-defender)
 87- [SentinelOne Cloud Funnel](https://ela.st/sentinel-one-cloud-funnel)
 88- [Sysmon Event ID 1 - Process Creation](https://ela.st/sysmon-event-1-setup)
 89- [Windows Process Creation Logs](https://ela.st/audit-process-creation)
 90"""
 91severity = "medium"
 92tags = [
 93    "Domain: Endpoint",
 94    "OS: Windows",
 95    "Use Case: Threat Detection",
 96    "Tactic: Credential Access",
 97    "Resources: Investigation Guide",
 98    "Data Source: Elastic Endgame",
 99    "Data Source: Elastic Defend",
100    "Data Source: Windows Security Event Logs",
101    "Data Source: Microsoft Defender XDR",
102    "Data Source: Sysmon",
103    "Data Source: SentinelOne",
104    "Data Source: Crowdstrike",
105]
106timestamp_override = "event.ingested"
107type = "eql"
108
109query = '''
110process where host.os.type == "windows" and event.type == "start" and
111 (
112    (?process.pe.original_file_name in ("Cmd.Exe","PowerShell.EXE")) or
113    (process.name : ("cmd.exe", "powershell.exe"))
114 ) and
115
116 /* Create Symbolic Link to Shadow Copies */
117 process.args : ("*mklink*", "*SymbolicLink*") and process.command_line : ("*HarddiskVolumeShadowCopy*")
118'''
119
120
121[[rule.threat]]
122framework = "MITRE ATT&CK"
123
124[[rule.threat.technique]]
125id = "T1003"
126name = "OS Credential Dumping"
127reference = "https://attack.mitre.org/techniques/T1003/"
128
129[[rule.threat.technique.subtechnique]]
130id = "T1003.002"
131name = "Security Account Manager"
132reference = "https://attack.mitre.org/techniques/T1003/002/"
133
134[[rule.threat.technique.subtechnique]]
135id = "T1003.003"
136name = "NTDS"
137reference = "https://attack.mitre.org/techniques/T1003/003/"
138
139[rule.threat.tactic]
140id = "TA0006"
141name = "Credential Access"
142reference = "https://attack.mitre.org/tactics/TA0006/"
143
144[[rule.threat]]
145framework = "MITRE ATT&CK"
146
147[[rule.threat.technique]]
148id = "T1006"
149name = "Direct Volume Access"
150reference = "https://attack.mitre.org/techniques/T1006/"
151
152[rule.threat.tactic]
153id = "TA0005"
154name = "Defense Evasion"
155reference = "https://attack.mitre.org/tactics/TA0005/"