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patel-bhavin
74 lines
2.8 KiB
YAML
74 lines
2.8 KiB
YAML
name: Linux At Allow Config File Creation
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id: 977b3082-5f3d-11ec-b954-acde48001122
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version: 1
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date: '2021-12-17'
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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: The following analytic identifies a suspicious file creation of /etc/at.allow
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or /etc/at.deny. These 2 files are commonly abused by malware, adversaries or red
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teamers to persist on the targeted or compromised host. These config files can restrict
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or allow user to execute "at" application (another schedule task application in
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linux). attacker can create a user or add the compromised username to that config
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file to execute "at" to schedule it malicious code. This anomaly detection can be
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a good indicator to investigate further the entry in created config file and who
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created it to verify if it is a false positive.
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search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
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as lastTime FROM datamodel=Endpoint.Filesystem where Filesystem.file_path IN ("*/etc/at.allow",
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"*/etc/at.deny") by Filesystem.dest Filesystem.file_create_time Filesystem.file_name
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Filesystem.process_guid Filesystem.file_path | `drop_dm_object_name(Filesystem)`
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| `security_content_ctime(lastTime)` | `security_content_ctime(firstTime)` | `linux_at_allow_config_file_creation_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 file name, file path, and process_guid executions from your endpoints into the Endpoint datamodel.
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If you are using Sysmon, you can use the Add-on for Linux Sysmon from Splunkbase.
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known_false_positives: Administrator or network operator can create this file for
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automation purposes. Please update the filter macros to remove false positives.
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references:
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- https://linuxize.com/post/at-command-in-linux/
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tags:
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analytic_story:
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- Linux Privilege Escalation
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- Linux Persistence Techniques
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- Linux Living Off The Land
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automated_detection_testing: passed
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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: 50
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context:
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- Source:Endpoint
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- Stage:Privilege Escalation
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- Stage:Persistence
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dataset:
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- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1053.001/at_execution/sysmon_linux.log
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impact: 50
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kill_chain_phases:
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- Exploitation
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message: A file $file_name$ is created in $file_path$ on $dest$
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mitre_attack_id:
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- T1053.003
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- T1053
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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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- Filesystem.dest
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- Filesystem.file_create_time
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- Filesystem.file_name
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- Filesystem.process_guid
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- Filesystem.file_path
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risk_score: 25
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security_domain: endpoint
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asset_type: Endpoint
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