A suspicious file modification on a Linux device targeted the ~/.bash_profile file, apparently adding a new line. What was the full command string that was appended?

DeviceFileEvents
| where FileName == ".bash_profile"
| where FolderPath startswith "/home/" or FolderPath endswith "/.bash_profile"
| where ActionType in ("FileCreated", "FileModified", "FileWrite", "FileWritten")
| project TimeGenerated, DeviceName, InitiatingProcessAccountName, InitiatingProcessCommandLine, FolderPath, FileName, AdditionalFields
| extend AppendedContent = tostring(AdditionalFields.content_added)
| project TimeGenerated, DeviceName, InitiatingProcessAccountName, InitiatingProcessCommandLine, FolderPath, AppendedContent

let target = "bash_profile";
union DeviceFileEvents, DeviceEvents, DeviceProcessEvents
| where FileName has target or FolderPath has target or InitiatingProcessCommandLine has target or ProcessCommandLine has target or tostring(AdditionalFields) has target
| extend Context = tostring(coalesce(InitiatingProcessCommandLine, ProcessCommandLine, AdditionalFields))
// try to extract common append patterns: echo/printf with >>, sed -i append, here-doc (cat <<EOF >> file)
| extend echo_match = extract(@"(?i)([^;\n]{0,300}>>\s*(?:~/)?\.?bash_profile)", 1, Context)
| extend sed_match  = extract(@"(?i)(sed\s+-i[^\r\n]*\$?a\\[^\n\r]*\s+(?:~/)?\.?bash_profile)", 1, Context)
| extend heredoc_match = extract(@"(?i)(<<[^>\n\r]{0,200}>>\s*(?:~/)?\.?bash_profile)", 1, Context)
| extend appended_command = trim(" ", coalesce(echo_match, sed_match, heredoc_match))
| where isnotempty(appended_command)
| project TimeGenerated, DeviceName, FileName, FolderPath, ActionType, InitiatingProcessFileName, InitiatingProcessId, InitiatingProcessCommandLine, ProcessCommandLine, appended_command, AdditionalFields
| order by TimeGenerated desc
| take 50

// Search for .bash_profile modifications and extract appended command strings
union isfuzzy=true DeviceFileEvents, DeviceEvents
| where TimeGenerated >= ago(7d)
// Filter likely file write/modify actions
| where ActionType has_any ("FileCreated","FileModified","FileWrite","FileChange","FileWriteEnd","FileAttributeChanged","FileOverwritten","Modified","Write","Append","Update","FileSaved")
// Narrow to bash_profile filename or path
| where FileName has "bash_profile" or FolderPath has "bash_profile" or FileName endswith "bash_profile" or FolderPath endswith "bash_profile"
// Safely parse AdditionalFields if present
| extend AdditionalFields_dyn = iif(isnull(AdditionalFields) or tostring(AdditionalFields) == "", dynamic({}), todynamic(AdditionalFields))
// Try to extract appended command from common keys
| extend appended_command = coalesce(
    tostring(AdditionalFields_dyn.append),
    tostring(AdditionalFields_dyn.appended),
    tostring(AdditionalFields_dyn.appended_text),
    tostring(AdditionalFields_dyn.apendedCommand),
    tostring(AdditionalFields_dyn.new_line),
    tostring(AdditionalFields_dyn.NewLine),
    tostring(AdditionalFields_dyn.command),
    tostring(AdditionalFields_dyn.Command),
    tostring(AdditionalFields_dyn.Content),
    tostring(AdditionalFields_dyn.lines),
    tostring(AdditionalFields_dyn.line),
    tostring(RegistryValueData),
    tostring(PreviousFileName),
    tostring(PreviousFolderPath)
)
// Also consider command lines from processes and other fields
| extend possible_cmds = pack_array(
    appended_command,
    tostring(InitiatingProcessCommandLine),
    tostring(ProcessCommandLine),
    tostring(AdditionalFields_dyn.command_line),
    tostring(AdditionalFields_dyn.cmd),
    tostring(AdditionalFields_dyn.cmdline),
    tostring(RegistryValueData),
    tostring(PreviousFileName)
)
// Unpack possible command candidates
| mv-expand possible_cmd = possible_cmds to typeof(string)
| where isnotempty(possible_cmd)
// Clean whitespace
| extend possible_cmd = trim(" \t\n\r", possible_cmd)
// Group identical appended strings and show sample events (limit samples to 10 per group)
| summarize Count = count(), Samples = take_any(pack('TimeGenerated', TimeGenerated,'DeviceName', DeviceName,'ActionType', ActionType,'FileName', FileName,'FolderPath', FolderPath,'InitiatingProcessFileName', InitiatingProcessFileName,'InitiatingProcessCommandLine', InitiatingProcessCommandLine,'ProcessCommandLine', ProcessCommandLine,'Extracted', possible_cmd), 10) by possible_cmd
| where Count > 0
| order by Count desc
| project AppendedCommand = possible_cmd, Count, Samples
| take 100

DeviceFileEvents
| where FolderPath endswith '/.bash_profile' and ActionType in~ ('FileCreate', 'FileCreated', 'FileModify', 'FileModified')
| join kind=inner (DeviceInfo | where OSPlatform == 'Linux') on DeviceId
| project Timestamp, DeviceName, FolderPath, InitiatingProcessCommandLine
| order by Timestamp desc
| take 10

DeviceProcessEvents
| join kind=inner (
    DeviceInfo
    | where tolower(OSPlatform) == "linux"
) on DeviceId
| where tolower(ProcessCommandLine) has ".bash_profile"
    // Filter for known shell appends like >>. You can broaden or adjust as needed.
    // If you specifically suspect 'echo "content" >> ~/.bash_profile', you might do:
    //   where tolower(ProcessCommandLine) has " >> "
| project TimeGenerated, DeviceName, AccountName, ProcessCommandLine
| order by TimeGenerated desc

// 1. Identify all Linux devices
let LinuxDeviceIds = DeviceInfo
  | where OSPlatform == "Linux"
  | distinct DeviceId;

// 2. Find .bash_profile file events on Linux devices
DeviceFileEvents
  | where DeviceId in (LinuxDeviceIds)
  | where FileName == ".bash_profile"
  | where ActionType in ("FileCreated", "FileModified", "FileOverwritten")

  // 3. Filter for append operations
  | where InitiatingProcessCommandLine has ">>" or InitiatingProcessCommandLine has "tee -a"

  // 4. Project relevant details
  | project TimeGenerated,
            DeviceName,
            FilePath = strcat(FolderPath, "/", FileName),
            AppendingProcess = InitiatingProcessFileName,
            AppendingCommandLine = InitiatingProcessCommandLine

  // 5. Sort by time
  | sort by TimeGenerated desc

DeviceFileEvents
| where FileName == ".bash_profile"
| where ActionType in ("FileModified", "FileCreated")
| extend FullPath = strcat(FolderPath, "/", FileName)
| where FullPath endswith "/.bash_profile"
| project TimeGenerated, DeviceName, InitiatingUser = strcat(InitiatingProcessAccountName, "@", InitiatingProcessAccountDomain), InitiatingProcessFile = InitiatingProcessFileName, InitiatingProcessId, CommandLine = InitiatingProcessCommandLine
| sort by TimeGenerated desc