splApache-2.0from splunk/security_content

Linux Indicator Removal Clear Cache

The following analytic detects processes that clear or free page cache on a Linux system. It leverages Endpoint Detection and Response (EDR) data, focusing on specific command-line executions involving the kernel system request `drop_caches`. This activity is significant as it may indicate an attempt to delete forensic evidence or the presence of wiper malware like Awfulshred. If confirmed malicious, this behavior could allow an attacker to cover their tracks, making it difficult to investigate other malicious activities or system compromises.

Quality

FP risk

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Forks

Views

Rule sourcedetections/endpoint/linux_indicator_removal_clear_cache.yml

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
  WHERE Processes.process_name IN ("dash", "sudo", "bash")
    AND
    Processes.process  IN("* echo 3 &gt; *", "* echo 2 &gt; *","* echo 1 &gt; *")
    AND
    Processes.process = "*/proc/sys/vm/drop_caches"
  BY Processes.action Processes.dest Processes.original_file_name
     Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
     Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
     Processes.process Processes.process_exec Processes.process_guid
     Processes.process_hash Processes.process_id Processes.process_integrity_level
     Processes.process_name Processes.process_path Processes.user
     Processes.user_id Processes.vendor_product
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `linux_indicator_removal_clear_cache_filter`