Terrance DeJesus
5769a21867
* updated content to reflect changes from Security Docs team
* Update rules/linux/execution_flock_binary.toml
* Update rules/linux/execution_expect_binary.toml
* TOML linting
* added escape for crdential_access_spn_attribute_modified.toml
(cherry picked from commit e9f5585a9f)
94 lines
4.2 KiB
TOML
94 lines
4.2 KiB
TOML
[metadata]
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creation_date = "2022/03/02"
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maturity = "production"
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updated_date = "2022/04/29"
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[rule]
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author = ["Elastic", "Austin Songer"]
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description = """
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Identifies the use of Windows Work Folders to execute a potentially masqueraded control.exe file in the current working
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directory. Misuse of Windows Work Folders could indicate malicious activity.
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"""
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from = "now-9m"
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index = ["winlogbeat-*", "logs-windows.*"]
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language = "eql"
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license = "Elastic License v2"
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name = "Signed Proxy Execution via MS Work Folders"
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note = """## Triage and analysis
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### Investigating Signed Proxy Execution via MS Work Folders
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Work Folders is a role service for file servers running Windows Server that provides a consistent way for users to access
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their work files from their PCs and devices. This allows users to store work files and access them from anywhere. When
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called, Work Folders will automatically execute any Portable Executable (PE) named control.exe as an argument before
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accessing the synced share.
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Using Work Folders to execute a masqueraded control.exe could allow an adversary to bypass application controls and
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increase privileges.
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#### Possible investigation steps
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- Investigate the process tree starting with parent process WorkFolders.exe and child process control.exe to determine
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if other child processes spawned during execution.
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- Trace the activity related to the control.exe binary to identify any continuing intrusion activity on the host.
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- Examine the location of the WorkFolders.exe binary to determine if it was copied to the location of the control.exe
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binary. It resides in the System32 directory by default.
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- Review the control.exe binary executed with Work Folders to determine maliciousness such as additional host activity
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or network traffic.
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- Determine if control.exe was synced to sync share, indicating potential lateral movement.
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- Review how control.exe was originally delivered on the host, such as emailed, downloaded from the web, or written to
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disk from a separate binary.
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### False positive analysis
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- Windows Work Folders are used legitimately by end users and administrators for file sharing and syncing but not in the
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instance where a suspicious control.exe is passed as an argument.
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### Response and remediation
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- Initiate the incident response process based on the outcome of the triage.
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- Isolate the involved host to prevent further post-compromise behavior.
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- Review the Work Folders synced share to determine if the control.exe was shared and if so remove it.
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- If no lateral movement was identified during investigation, take the affected host offline if possible and remove the
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control.exe binary as well as any additional artifacts identified during investigation.
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- Review integrating Windows Information Protection (WIP) to enforce data protection by encrypting the data on PCs using
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Work Folders.
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- Confirm with the user whether this was expected or not, and reset their password.
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## Config
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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.
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"""
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references = [
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"https://docs.microsoft.com/en-us/windows-server/storage/work-folders/work-folders-overview",
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"https://twitter.com/ElliotKillick/status/1449812843772227588",
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"https://lolbas-project.github.io/lolbas/Binaries/WorkFolders/",
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]
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risk_score = 47
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rule_id = "ad0d2742-9a49-11ec-8d6b-acde48001122"
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severity = "medium"
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tags = ["Elastic", "Host", "Windows", "Threat Detection", "Defense Evasion"]
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timestamp_override = "event.ingested"
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type = "eql"
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query = '''
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process where event.type in ("start","process_started")
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and process.name : "control.exe" and process.parent.name : "WorkFolders.exe"
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and not process.executable : ("?:\\Windows\\System32\\control.exe", "?:\\Windows\\SysWOW64\\control.exe")
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'''
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[[rule.threat]]
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framework = "MITRE ATT&CK"
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[[rule.threat.technique]]
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id = "T1218"
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name = "Signed Binary Proxy Execution"
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reference = "https://attack.mitre.org/techniques/T1218/"
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[rule.threat.tactic]
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id = "TA0005"
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name = "Defense Evasion"
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reference = "https://attack.mitre.org/tactics/TA0005/"
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