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https://github.com/splunk/security_content
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Michael Haag
89 lines
3.4 KiB
YAML
89 lines
3.4 KiB
YAML
name: Linux pkexec Privilege Escalation
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id: 03e22c1c-8086-11ec-ac2e-acde48001122
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version: 1
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date: '2022-01-28'
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author: Michael Haag, Splunk
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type: TTP
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datamodel:
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- Endpoint
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description: The following analytic identifies `pkexec` spawning with no command-line
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arguments. A vulnerability in Polkit's pkexec component identified as CVE-2021-4034
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(PwnKit) which is present in the default configuration of all major Linux distributions
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and can be exploited to gain full root privileges on the system.
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search: '| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes
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where Processes.process_name=pkexec by _time Processes.dest Processes.process_id
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Processes.parent_process_name Processes.process_name Processes.process Processes.process_path
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| `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
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| regex process="(^.{1}$)" | `linux_pkexec_privilege_escalation_filter`'
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how_to_implement: Depending on the EDR product in use, there are multiple ways to
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"null" the command-line field, Processes.process. Two that may be useful `process="(^.{0}$)"`
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or `| where isnull(process)`. To generate data for this behavior, Sysmon for Linux
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was utilized. To successfully implement this search you need to be ingesting information
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on process that include the name of the process responsible for the changes from
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your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition,
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confirm the latest CIM App 4.20 or higher is installed and the latest TA for the
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endpoint product.
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known_false_positives: False positives may be present, filter as needed.
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references:
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- https://www.reddit.com/r/crowdstrike/comments/sdfeig/20220126_cool_query_friday_hunting_pwnkit_local/
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- https://linux.die.net/man/1/pkexec
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- https://www.bleepingcomputer.com/news/security/linux-system-service-bug-gives-root-on-all-major-distros-exploit-released/
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- https://access.redhat.com/security/security-updates/#/?q=polkit&p=1&sort=portal_publication_date%20desc&rows=10&portal_advisory_type=Security%20Advisory&documentKind=PortalProduct
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tags:
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analytic_story:
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- Linux Privilege Escalation
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- Linux Living Off The Land
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confidence: 70
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context:
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- Source:Endpoint
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- Stage:Defense Evasion
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cve:
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- CVE-2021-4034
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dataset:
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- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1068/zoom_child_process/linux-sysmon.log
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impact: 80
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kill_chain_phases:
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- Exploitation
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message: An instance of $parent_process_name$ spawning $process_name$ was identified
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on endpoint $dest$ by user $user$ related to a local privilege escalation in polkit
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pkexec.
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mitre_attack_id:
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- T1068
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observable:
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- name: user
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type: User
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role:
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- Victim
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- name: dest
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type: Hostname
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role:
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- Victim
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- name: parent_process_name
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type: Process
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role:
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- Parent Process
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- name: process_name
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type: Process
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role:
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- Child Process
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product:
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- Splunk Enterprise
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- Splunk Enterprise Security
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- Splunk Cloud
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required_fields:
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- _time
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- Processes.dest
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- Processes.user
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- Processes.parent_process_name
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- Processes.parent_process
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- Processes.original_file_name
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- Processes.process_name
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- Processes.process
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- Processes.process_id
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- Processes.parent_process_path
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- Processes.process_path
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- Processes.parent_process_id
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risk_score: 56
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security_domain: endpoint
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asset_type: Endpoint
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