Mika Ayenson
aab23636e8
* Add new event_data fields (ObjectName, ProcessName)
* Add detection for LSASS Memory Dump Handle Access
* Reference an example of 120089 AccessMask presence
* modify query to increase performance and update the description to remove ("This rule").
* expand path to Elastic Agent ensure syntax consistency
* Optimize rule based on AccessMaskDescription and additional False Positives.
* add AccessMaskDescription keyword and rule tune to make sure AccessMask is used
* filter dllhost.exe and or the condition between AccessMask and AccessMaskDescription
* cleanup
(cherry picked from commit aa7d79cc53)
127 lines
4.9 KiB
TOML
127 lines
4.9 KiB
TOML
[metadata]
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creation_date = "2022/02/16"
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maturity = "production"
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updated_date = "2022/02/16"
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[rule]
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author = ["Elastic"]
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description = """
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Identifies handle requests for the Local Security Authority Subsystem Service (LSASS) object access with
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specific access masks that many tools with a capability to dump memory to disk use (0x1fffff, 0x1010, 0x120089).
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This rule is tool agnostic as it has been validated against a host of various LSASS dump tools such as SharpDump,
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Procdump, Mimikatz, Comsvcs etc. It detects this behavior at a low level and does not depend on a specific tool or dump
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file name.
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"""
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from = "now-9m"
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index = ["winlogbeat-*", "logs-system.*"]
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language = "eql"
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license = "Elastic License v2"
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name = "LSASS Memory Dump Handle Access"
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note = """## Triage and analysis.
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### Investigating
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Local Security Authority Server Service (LSASS) is a process in Microsoft Windows operating systems that is responsible
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for enforcing the security policy on the system. It verifies users logging on to a Windows computer or server, handles
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password changes, and creates access tokens.
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Adversaries may attempt to access credential material stored in the process memory of the LSASS. After a user logs on,
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the system generates and stores a variety of credential materials in LSASS process memory. This is meant to facilitate
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single sign-on (SSO) ensuring a user isn’t prompted each time resource access is requested. These credential materials
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can be harvested by an adversary using administrative user or SYSTEM privileges to conduct Lateral Movement using
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[Use Alternate Authentication Material](https://attack.mitre.org/techniques/T1550/).
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#### Possible investigation steps:
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- Validate the correct install path for the process that triggered this detection
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- Confirm that any AV or EDR solutions that trigger this detection have the correct install path
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### False Positive Analysis
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- There should be very few if any false positives for this rule. However, it may be tripped by AV or EDR solutions.
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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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- In case of specific credentials were compromised:
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- Reset the password for the accounts
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## Config
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Ensure advanced audit policies for Windows are enabled, specifically
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Object Access policies [Event ID 4656](https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4656) (Handle to an Object was Requested)
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```
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Computer Configuration >
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Policies >
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Windows Settings >
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Security Settings >
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Advanced Audit Policies Configuration >
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System Audit Policies >
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Object Access >
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Audit File System (Success,Failure)
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Audit Handle Manipulation (Success,Failure)
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```
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Also, this event generates only if the object’s [SACL](https://docs.microsoft.com/en-us/windows/win32/secauthz/access-control-lists) has the required ACE to handle the use of specific access rights.
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"""
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references = [
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"https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4656",
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"https://twitter.com/jsecurity101/status/1227987828534956033?s=20",
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"https://attack.mitre.org/techniques/T1003/001/",
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"https://threathunterplaybook.com/notebooks/windows/06_credential_access/WIN-170105221010.html",
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"http://findingbad.blogspot.com/2017/"
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]
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risk_score = 73
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rule_id = "208dbe77-01ed-4954-8d44-1e5751cb20de"
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severity = "high"
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tags = ["Elastic", "Host", "Windows", "Threat Detection", "Credential Access"]
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timestamp_override = "event.ingested"
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type = "eql"
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query = '''
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any where event.action == "File System" and event.code == "4656" and
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winlog.event_data.ObjectName : (
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"?:\\Windows\\System32\\lsass.exe",
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"\\Device\\HarddiskVolume?\\Windows\\System32\\lsass.exe",
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"\\Device\\HarddiskVolume??\\Windows\\System32\\lsass.exe") and
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/* The right to perform an operation controlled by an extended access right. */
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(winlog.event_data.AccessMask : ("0x1fffff" , "0x1010", "0x120089", "0x1F3FFF") or
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winlog.event_data.AccessMaskDescription : ("READ_CONTROL", "Read from process memory"))
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/* Common Noisy False Positives */
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and not winlog.event_data.ProcessName : (
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"?:\\Program Files\\*.exe",
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"?:\\Program Files (x86)\\*.exe",
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"?:\\Windows\\system32\\wbem\\WmiPrvSE.exe",
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"?:\\Windows\\System32\\dllhost.exe",
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"?:\\Windows\\System32\\svchost.exe",
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"?:\\Windows\\System32\\msiexec.exe",
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"?:\\ProgramData\\Microsoft\\Windows Defender\\*.exe",
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"?:\\Windows\\explorer.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 = "T1003"
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name = "OS Credential Dumping"
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reference = "https://attack.mitre.org/techniques/T1003/"
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[[rule.threat.technique.subtechnique]]
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id = "T1003.001"
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name = "LSASS Memory"
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reference = "https://attack.mitre.org/techniques/T1003/001/"
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[rule.threat.tactic]
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id = "TA0006"
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name = "Credential Access"
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reference = "https://attack.mitre.org/tactics/TA0006/"
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