LSASS Memory Dump Handle Access
editLSASS Memory Dump Handle Access
editIdentifies handle requests for the Local Security Authority Subsystem Service (LSASS) object access with specific access masks that many tools with a capability to dump memory to disk use (0x1fffff, 0x1010, 0x120089). This rule is tool agnostic as it has been validated against a host of various LSASS dump tools such as SharpDump, Procdump, Mimikatz, Comsvcs etc. It detects this behavior at a low level and does not depend on a specific tool or dump file name.
Rule type: eql
Rule indices:
- winlogbeat-*
- logs-system.*
Severity: high
Risk score: 73
Runs every: 5m
Searches indices from: now-9m (Date Math format, see also Additional look-back time
)
Maximum alerts per execution: 100
References:
- https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4656
- https://twitter.com/jsecurity101/status/1227987828534956033?s=20
- https://attack.mitre.org/techniques/T1003/001/
- https://threathunterplaybook.com/notebooks/windows/06_credential_access/WIN-170105221010.html
- http://findingbad.blogspot.com/2017/
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Credential Access
Version: 1
Rule authors:
- Elastic
Rule license: Elastic License v2
Investigation guide
edit## Triage and analysis ### Investigating LSASS Memory Dump Handle Access Local Security Authority Server Service (LSASS) is a process in Microsoft Windows operating systems that is responsible for enforcing security policy on the system. It verifies users logging on to a Windows computer or server, handles password changes, and creates access tokens. Adversaries may attempt to access credential material stored in LSASS process memory. After a user logs on,the system generates and stores a variety of credential materials in LSASS process memory. This is meant to facilitate single sign-on (SSO) ensuring a user isn’t prompted each time resource access is requested. These credential materials can be harvested by an adversary using administrative user or SYSTEM privileges to conduct lateral movement using [alternate authentication material](https://attack.mitre.org/techniques/T1550/). #### Possible investigation steps - Investigate the process execution chain (parent process tree). - Investigate other alerts associated with the user/host during the past 48 hours. - Validate the correct install path for the process that triggered this detection. ### False positive analysis - There should be very few if any false positives for this rule. However, it may be tripped by antivirus or endpoint detection and response solutions; check whether these solutions are installed on the correct paths. ### 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. - Scope compromised credentials and disable the accounts. - Reset passwords for the user account and other potentially compromised accounts (email, services, CRMs, etc.). ## Config Ensure advanced audit policies for Windows are enabled, specifically: 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) ``` Computer Configuration > Policies > Windows Settings > Security Settings > Advanced Audit Policies Configuration > System Audit Policies > Object Access > Audit File System (Success,Failure) Audit Handle Manipulation (Success,Failure) ``` 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 access control entry (ACE) to handle the use of specific access rights. 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.
Rule query
editany where event.action == "File System" and event.code == "4656" and winlog.event_data.ObjectName : ( "?:\\Windows\\System32\\lsass.exe", "\\Device\\HarddiskVolume?\\Windows\\System32\\lsass.exe", "\\Device\\HarddiskVolume??\\Windows\\System32\\lsass.exe") and /* The right to perform an operation controlled by an extended access right. */ (winlog.event_data.AccessMask : ("0x1fffff" , "0x1010", "0x120089", "0x1F3FFF") or winlog.event_data.AccessMaskDescription : ("READ_CONTROL", "Read from process memory")) /* Common Noisy False Positives */ and not winlog.event_data.ProcessName : ( "?:\\Program Files\\*.exe", "?:\\Program Files (x86)\\*.exe", "?:\\Windows\\system32\\wbem\\WmiPrvSE.exe", "?:\\Windows\\System32\\dllhost.exe", "?:\\Windows\\System32\\svchost.exe", "?:\\Windows\\System32\\msiexec.exe", "?:\\ProgramData\\Microsoft\\Windows Defender\\*.exe", "?:\\Windows\\explorer.exe")
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Credential Access
- ID: TA0006
- Reference URL: https://attack.mitre.org/tactics/TA0006/
-
Technique:
- Name: OS Credential Dumping
- ID: T1003
- Reference URL: https://attack.mitre.org/techniques/T1003/
-
Sub-technique:
- Name: LSASS Memory
- ID: T1003.001
- Reference URL: https://attack.mitre.org/techniques/T1003/001/