Detect Potential Cleartext Credentials in Command Line

KQL Queries

KQL (Kusto Query Language) query to identify potential cleartext credentials in command lines, leveraging Microsoft Defender for Endpoint or other platforms like Azure Monitor Logs:

DeviceProcessEvents
| where Timestamp > ago(7d)  // Adjust the time frame as needed
| where ProcessCommandLine has_any ("password", "pwd", "pass", "secret", "key", "credential", "login")
| extend SuspiciousWords = extract_all(@"(?i)(password\s*[:=]\s*\S+|pwd\s*[:=]\s*\S+|pass\s*[:=]\s*\S+|secret\s*[:=]\s*\S+|key\s*[:=]\s*\S+|credential\s*[:=]\s*\S+|login\s*[:=]\s*\S+)", ProcessCommandLine)
| where array_length(SuspiciousWords) > 0
| project Timestamp, DeviceName, AccountName, FileName, FolderPath, ProcessCommandLine, SuspiciousWords
| extend AccountDomain = tostring(split(AccountName, "\\", 0)), Username = tostring(split(AccountName, "\\", 1))
| summarize Count = count(), Commands = make_set(ProcessCommandLine) by Timestamp, DeviceName, AccountName, FileName, FolderPath, ProcessCommandLine
| order by Count desc

Key Features of the Query:

Filters Suspicious Command Lines:
- Targets command lines with keywords commonly associated with credentials like password, pwd, secret, etc.
Extracts Potential Credentials:
- Uses regex to extract possible key-value pairs (e.g., password=1234).
Aggregation for Context:
- Groups occurrences by DeviceName, AccountDomain, and Username to provide context.
Summarization and Ordering:
- Highlights accounts and devices with the highest occurrences of potential issues.

How It Works:

Extract_all Function: This regex extracts any matching patterns from the command line that indicate potential cleartext credentials.
Dynamic Analysis: Produces a dynamic array of potential matches, ensuring flexibility in parsing varying formats.
Adjustable Time Frame: Allows tuning for recent or historical analysis.

Use Case Scenarios:

Detect accidental or intentional exposure of credentials in scripts or commands.
Investigate potential misuse by attackers or internal personnel.

KQL query will detect potential cleartext credentials in command lines. This query will look for process execution events that may contain credentials in their command line arguments:

// Excluding known false positive processes
let ExcludedProcesses = dynamic(["WerFault.exe", "WerFaultSecure.exe", "SenseNDR.exe"]);
// Define patterns to identify potential user and password command line arguments
let PossibleUserCLI = dynamic(["/U", "/User", "/username", "-u", "-user", "--user", "--username"]);
let PossiblePasswordCLI = dynamic(["/P", "/password", "/pass", "-p", "-password", "-pw", "-pass", "--pass", "--password"]);
// Query DeviceProcessEvents table
DeviceProcessEvents
| where not (FileName in~ ExcludedProcesses) // Exclude known false positive processes
| where ProcessCommandLine has_any (PossibleUserCLI) // Match potential user command line arguments
| where ProcessCommandLine has_any (PossiblePasswordCLI) // Match potential password command line arguments
| summarize
    TotalEvents = count(),
    UniqueDevices = dcount(DeviceName),
    UniqueUsers = dcount(AccountName)
    by ProcessCommandLine, FileName, FolderPath, bin(TimeGenerated, 1h)
| order by TotalEvents desc
| project TimeGenerated, ProcessCommandLine, FileName, FolderPath, TotalEvents, UniqueDevices, UniqueUsers

Explanation:

Pattern Matching: The PossibleUserCLI and PossiblePasswordCLI dynamic arrays contain common command line arguments for user and password.
Filtering: The where clauses filter the DeviceProcessEvents table to exclude known false positive processes and retain only events matching the specified patterns.
Summarisation: The summarise statement aggregates the data to count the total number of events, unique devices, and unique users for each command line, file name, and folder path.
Ordering: The results are ordered by the total number of events in descending order.
Projection: The project statement selects the relevant columns for the final output.

KQL query to discover potential cleartext credentials in command lines without using Instead, we'll use the CloudAppEvents table:

// Define patterns to identify potential user and password command line arguments
let PossibleUserCLI = dynamic(["/U", "/User", "/username", "-u", "-user", "--user", "--username"]);
let PossiblePasswordCLI = dynamic(["/P", "/password", "/pass", "-p", "-password", "-pw", "-pass", "--pass", "--password"]);
// Query CloudAppEvents table
CloudAppEvents
| where EventType == "ProcessCreation" // Filter for process creation events
| where CommandLine has_any (PossibleUserCLI) // Match potential user command line arguments
| where CommandLine has_any (PossiblePasswordCLI) // Match potential password command line arguments
| summarize
    TotalEvents = count(),
    UniqueDevices = dcount(DeviceName),
    UniqueUsers = dcount(AccountName)
    by CommandLine, AppName, FolderPath, bin(TimeGenerated, 1h)
| order by TotalEvents desc
| project TimeGenerated, CommandLine, AppName, FolderPath, TotalEvents, UniqueDevices, UniqueUsers

Explanation:

Pattern Matching: The PossibleUserCLI and PossiblePasswordCLI dynamic arrays contain common command line arguments for user and password.
Filtering: The where clauses filter the CloudAppEvents table to retain only process creation events matching the specified patterns.
Summarisation: The summarise statement aggregates the data to count the total number of events, unique devices, and unique users for each command line, app name, and folder path.
Ordering: The results are ordered by the total number of events in descending order.
Projection: The project statement selects the relevant columns for the final output.

KQL query to discover potential cleartext credentials in command lines using the DeviceFileEvents table:

// Define patterns to identify potential user and password command line arguments
let PossibleUserCLI = dynamic(["/U", "/User", "/username", "-u", "-user", "--user", "--username"]);
let PossiblePasswordCLI = dynamic(["/P", "/password", "/pass", "-p", "-password", "-pw", "-pass", "--pass", "--password"]);
// Query DeviceFileEvents table
DeviceFileEvents
| where ActionType == "FileCreated" or ActionType == "FileModified" // Filter for file creation or modification events
| where FileName endswith ".log" or FileName endswith ".txt" // Filter for log or text files
| where FilePath has_any (PossibleUserCLI) // Match potential user command line arguments
| where FilePath has_any (PossiblePasswordCLI) // Match potential password command line arguments
| summarize
    TotalEvents = count(),
    UniqueDevices = dcount(DeviceName),
    UniqueUsers = dcount(AccountName)
    by FilePath, FileName, FolderPath, bin(TimeGenerated, 1h)
| order by TotalEvents desc
| project TimeGenerated, FilePath, FileName, FolderPath, TotalEvents, UniqueDevices, UniqueUsers

Explanation:

Pattern Matching: The PossibleUserCLI and PossiblePasswordCLI dynamic arrays contain common command line arguments for user and password.
Filtering: The where clauses filter the DeviceFileEvents table to retain only file creation or modification events for log or text files matching the specified patterns.
Summarisation: The summarise statement aggregates the data to count the total number of events, unique devices, and unique users for each file path, file name, and folder path.
Ordering: The results are ordered by the total number of events in descending order.
Projection: The project statement selects the relevant columns for the final output.

This query should help you identify potential cleartext credentials in command lines within an environment.

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Last updated 1 year ago

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KQL Queries

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