The ability to execute commands silently using cmd.exe
while redirecting both standard output (STDOUT) and standard error (STDERR) is a common technique employed in both legitimate administrative tasks and malicious activities.
This method ensures that the command execution remains hidden from the user, while capturing or discarding the output for further processing.
/Q
and /C
:/Q
switch turns off echo, ensuring that commands do not display their execution./C
switch executes the specified command and then terminates the command processor.cmd.exe /Q /C "command"
cmd.exe
separates outputs into two streams: 2>&1
. This redirects STDERR to STDOUT, which can then be redirected to a file, a pipe, or discarded.command > output.log 2>&1
command > alloutput.log 2>&1
command > nul 2>&1
Several open-source tools and frameworks leverage silent execution with redirection for stealthy operations:
cmd.exe /Q /C
along with redirection for capturing outputs remotely.Identifying silent cmd.exe executions with redirected outputs is crucial in detecting potential malicious activities. Key indicators include:
/Q
, /C
, and redirection operators (>
, 2>&1
).wmiprvse.exe
.Example query for detection using Microsoft Defender for Endpoint:
DeviceProcessEvents
| where FileName =~ "cmd.exe"
| where ProcessCommandLine has_all ("/Q", "/C")
| where ProcessCommandLine has_any ("&1", "2>&1")
Silent execution of cmd.exe
with redirected STDERR and STDOUT is a powerful technique for both legitimate automation and adversarial tactics.
While it enables efficient command execution without user interaction, its misuse necessitates vigilant monitoring through process auditing, event logging, and advanced threat-hunting queries.
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