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tccontre
72 lines
2.5 KiB
YAML
72 lines
2.5 KiB
YAML
name: Linux Iptables Firewall Modification
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id: 309d59dc-1e1b-49b2-9800-7cf18d12f7b7
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version: 1
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date: '2022-04-05'
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author: Teoderick Contreras, Splunk
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type: Anomaly
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datamodel:
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- Endpoint
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description: This analytic looks for suspicious commandline that modify the iptables firewall setting of a linux machine.
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This technique was seen in cyclopsblink malware where it modifies the firewall setting of the compromised machine to allow
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traffic to its tcp port that will be used to communicate with its C2 server.
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search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes
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where Processes.process = "*iptables *" AND Processes.process = "* --dport *" AND Processes.process = "* ACCEPT*"
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by Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
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Processes.process_guid Processes.dest Processes.user Processes.parent_process_name
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| `drop_dm_object_name(Processes)`
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| `security_content_ctime(firstTime)`
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| `security_content_ctime(lastTime)`
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| `linux_iptables_firewall_modification_filter`'
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how_to_implement: To successfully implement this search, you need to be ingesting
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logs with the process name, parent process, and command-line executions from your
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endpoints. If you are using Sysmon, you can use the Add-on for Linux Sysmon from
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Splunkbase.
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known_false_positives: administrator may do this commandline for auditing and testing purposes.
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In this scenario filter is needed.
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references:
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- https://www.ncsc.gov.uk/files/Cyclops-Blink-Malware-Analysis-Report.pdf
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- https://www.trendmicro.com/en_us/research/22/c/cyclops-blink-sets-sights-on-asus-routers--.html
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tags:
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analytic_story:
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- Cyclops BLink
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asset_type: Endpoint
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cis20:
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- CIS 3
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- CIS 5
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- CIS 16
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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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dataset:
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- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/cyclopsblink/sysmon_linux.log
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impact: 70
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kill_chain_phases:
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- Exploitation
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message: A commandline $process$ that may modify iptables firewall on $dest$
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mitre_attack_id:
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- T1562.004
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- T1562
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nist:
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- DE.CM
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observable:
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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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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.process_name
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- Processes.process
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- Processes.process_id
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- Processes.parent_process_id
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risk_score: 49
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security_domain: endpoint
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