IMPORTANT: No additional bug fixes or documentation updates
will be released for this version. For the latest information, see the
current release documentation.
Persistence via Update Orchestrator Service Hijack
editPersistence via Update Orchestrator Service Hijack
editIdentifies potential hijacking of the Microsoft Update Orchestrator Service to establish persistence with an integrity level of SYSTEM.
Rule type: eql
Rule indices:
- winlogbeat-*
- logs-endpoint.events.*
- logs-windows.*
Severity: high
Risk score: 73
Runs every: 5 minutes
Searches indices from: now-9m (Date Math format, see also Additional look-back time
)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Persistence
- CVE-2020-1313
Version: 101 (version history)
Added (Elastic Stack release): 7.10.0
Last modified (Elastic Stack release): 8.5.0
Rule authors: Elastic
Rule license: Elastic License v2
Investigation guide
edit## Triage and analysis ### Investigating Persistence via Update Orchestrator Service Hijack Windows Update Orchestrator Service is a DCOM service used by other components to install Windows updates that are already downloaded. Windows Update Orchestrator Service was vulnerable to elevation of privileges (any user to local system) due to an improper authorization of the callers. The vulnerability affected the Windows 10 and Windows Server Core products. Fixed by Microsoft on Patch Tuesday June 2020. This rule will detect uncommon processes spawned by `svchost.exe` with `UsoSvc` as the command line parameters. Attackers can leverage this technique to elevate privileges or maintain persistence. #### Possible investigation steps - 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. - Investigate any abnormal behavior by the subject process such as network connections, registry or file modifications, and any spawned child processes. - Investigate other alerts associated with the user/host during the past 48 hours. - Assess whether this behavior is prevalent in the environment by looking for similar occurrences across hosts. - Retrieve the process executable and determine if it is malicious: - Use a private sandboxed malware analysis system to perform analysis. - Observe and collect information about the following activities: - Attempts to contact external domains and addresses. - File and registry access, modification, and creation activities. - Service creation and launch activities. - Scheduled task creation. - Use the PowerShell Get-FileHash cmdlet to get the files' SHA-256 hash values. - Search for the existence and reputation of the hashes in resources like VirusTotal, Hybrid-Analysis, CISCO Talos, Any.run, etc. ### False positive analysis - This activity is unlikely to happen legitimately. Benign true positives (B-TPs) can be added as exceptions if necessary. ### 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. - If the triage identified malware, search the environment for additional compromised hosts. - Implement temporary network rules, procedures, and segmentation to contain the malware. - Stop suspicious processes. - Immediately block the identified indicators of compromise (IoCs). - Inspect the affected systems for additional malware backdoors like reverse shells, reverse proxies, or droppers that attackers could use to reinfect the system. - Remove and block malicious artifacts identified during triage. - 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. - Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components. - Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector. - 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
editprocess where event.type == "start" and process.parent.executable : "C:\\Windows\\System32\\svchost.exe" and process.parent.args : "UsoSvc" and not process.executable : ("?:\\ProgramData\\M icrosoft\\Windows\\UUS\\Packages\\*\\amd64\\MoUsoCoreWorker.exe", "?:\\Windows\\System32\\UsoClient.exe", "?:\\Windows\\System32\\MusNotification.exe", "?:\\Windows\\System32\\MusNotificationUx.exe", "?:\\Windows\\System32\\MusNotifyIcon.exe", "?:\\Windows\\System32\\WerFault.exe", "?:\\Windows\\System32\\WerMgr.exe", "?:\\Windows\\UUS\\amd64\\MoUsoCoreWorker.exe", "?:\\Windows\\System32\\MoUsoCoreWorker.exe", "?:\\Windows\\UUS\\amd64\\UsoCoreWorker.exe", "?:\\Windows\\System32\\UsoCoreWorker.exe", "?:\\Program Files\\Common Files\\microsoft shared\\ClickToRun\\OfficeC2RClient.exe") and not process.name : ("MoUsoCoreWorker.exe", "OfficeC2RClient.exe")
Threat mapping
editFramework: MITRE ATT&CKTM
-
Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
-
Technique:
- Name: Create or Modify System Process
- ID: T1543
- Reference URL: https://attack.mitre.org/techniques/T1543/
Rule version history
edit- Version 101 (8.5.0 release)
-
-
Updated query, changed from:
process where event.type == "start" and process.parent.executable : "C:\\Windows\\System32\\svchost.exe" and process.parent.args : "UsoSvc" and not process.executable : ("?:\\ProgramData\\M icrosoft\\Windows\\UUS\\Packages\\*\\amd64\\MoUsoCoreWorker.exe", "?:\\Windows\\System32\\UsoClient.exe", "?:\\Windows\\System32\\MusNotification.exe", "?:\\Windows\\System32\\MusNotificationUx.exe", "?:\\Windows\\System32\\MusNotifyIcon.exe", "?:\\Windows\\System32\\WerFault.exe", "?:\\Windows\\System32\\WerMgr.exe", "?:\\Windows\\UUS\\amd64\\MoUsoCoreWorker.exe", "?:\\Windows\\System32\\MoUsoCoreWorker.exe", "?:\\Windows\\UUS\\amd64\\UsoCoreWorker.exe", "?:\\Windows\\System32\\UsoCoreWorker.exe", "?:\\Program Files\\Common Files\\microsoft shared\\ClickToRun\\OfficeC2RClient.exe")
-
- Version 7 (8.4.0 release)
-
-
Updated query, changed from:
process where event.type == "start" and process.parent.executable : "C:\\Windows\\System32\\svchost.exe" and process.parent.args : "UsoSvc" and not process.executable : ( "C:\\Windows\\System32\\UsoClient.exe", "C:\\Windows\\System32\\MusNotification.exe", "C:\\Windows\\System32\\MusNotificationUx.exe", "C:\\Windows\\System32\\MusNotifyIcon.exe", "C:\\Windows\\System32\\WerFault.exe", "C:\\Windows\\System32\\WerMgr.exe" )
-
- Version 5 (8.2.0 release)
-
- Formatting only
- Version 4 (7.12.0 release)
-
-
Updated query, changed from:
event.category:process and event.type:(start or process_started) and process.parent.name:svchost.exe and process.parent.args:(UsoSvc or usosvc) and not process.name:(UsoClient.exe or usoclient.exe or MusNotification.exe or musnotification.exe or MusNotificationUx.exe or musnotificationux.exe)
-
- Version 3 (7.11.2 release)
-
- Formatting only
- Version 2 (7.11.0 release)
-
- Formatting only