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Fix agent background python jobs #821

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Fix agent background python jobs #821

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b87da57
Fixing command 112 to execute in background, removing unnecessary log…
ruvolof Mar 1, 2026
c9f17e4
Fixing sys.stdout concurrent access with python agent background jobs.
ruvolof Mar 7, 2026
714bcba
Adding fix for background jobs in python agent to changelog.md
ruvolof Apr 13, 2026
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1 change: 1 addition & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
- **Security** in case of vulnerabilities.

## [Unreleased]
- Fixed background jobs for the python agent.

## [6.5.0] - 2026-03-08
- Updated Starkiller to v3.4.0
Expand Down
90 changes: 21 additions & 69 deletions empire/server/data/agent/agent.py
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Original file line number Diff line number Diff line change
Expand Up @@ -606,10 +606,9 @@ def dynamic_code_execute_wait_nosave(self, data, result_id):
try:
globals().update({'agent':self})
buffer = StringIO()
sys.stdout = buffer
exec_globals = {**globals(), 'print': lambda *a, **k: print(*a, **k, file=buffer)}
code_obj = compile(data, "<string>", "exec")
exec(code_obj, globals())
sys.stdout = sys.__stdout__
exec(code_obj, exec_globals)
results = buffer.getvalue()
self.packet_handler.send_message(self.packet_handler.build_response_packet(110, str(results), result_id))
self.tasks[result_id]["status"] = "completed"
Expand All @@ -634,10 +633,9 @@ def dynamic_code_execution_wait_save(self, data, result_id):
data = data[20:]
try:
buffer = StringIO()
sys.stdout = buffer
code_obj = compile(data, "<string>", "exec")
exec(code_obj, globals())
sys.stdout = sys.__stdout__
exec_globals = {**globals(), 'print': lambda *a, **k: print(*a, **k, file=buffer)}
exec(code_obj, exec_globals)
results = buffer.getvalue().encode("latin-1")
c = compress()
start_crc32 = c.crc32_data(results)
Expand Down Expand Up @@ -668,99 +666,53 @@ def dynamic_code_execution_wait_save(self, data, result_id):
)
self.tasks[result_id]["status"] = "error"

def disk_code_execution_wait_save(self, data, result_id):
def python_job_func(self, data, result_id):
"""
Execute on-disk code and wait for the results while saving output.
Execute python script, wait for the results and return stdout.
Adjusted for Windows and cross-platform compatibility.
Task 112
"""
try:
script_globals = {}
output_capture = io.StringIO()
sys.stdout = output_capture

try:
exec(data, script_globals)
except SyntaxError as e:
result = "[!] Syntax error in script: %s on line %d - %s" % (str(e), e.lineno, e.text)
self.packet_handler.send_message(
self.packet_handler.build_response_packet(0, result, result_id)
)
self.tasks[result_id]["status"] = "error"
return

except Exception as e:
result = "[!] Error executing script: %s" % str(e)
self.packet_handler.send_message(
self.packet_handler.build_response_packet(0, result, result_id)
)
self.tasks[result_id]["status"] = "error"
return
output_capture = io.StringIO()
script_globals = {'print': lambda *a, **k: print(*a, **k, file=output_capture)}

try:
exec(data, script_globals)
captured_output = output_capture.getvalue()

if captured_output:
result = "[*] Output from script:\n" + captured_output
else:
result = "[*] No output captured from the script.\n"

if 'output' in script_globals:
result += "[*] Output variable from script: \n" + str(script_globals['output'])

self.packet_handler.send_message(
self.packet_handler.build_response_packet(112, result, result_id)
)
self.tasks[result_id]["status"] = "completed"

except Exception as e:
except SyntaxError as e:
result = "[!] Syntax error in script: %s on line %d - %s" % (str(e), e.lineno, e.text)
self.packet_handler.send_message(
self.packet_handler.build_response_packet(
0, "error executing TASK_PYTHON_CMD_JOB: %s" % (e), result_id
)
self.packet_handler.build_response_packet(0, result, result_id)
)
self.tasks[result_id]["status"] = "error"

finally:
sys.stdout = sys.__stdout__
except Exception as e:
result = "[!] Error executing script: %s" % str(e)
self.packet_handler.send_message(
self.packet_handler.build_response_packet(0, result, result_id)
)
self.tasks[result_id]["status"] = "error"


def start_python_job(self, code, result_id):
# create a new code block with a defined method name
code_block = "def method():\n" + indent(code)

# register the code block
code_obj = compile(code_block, "<string>", "exec")
# code needs to be in the global listing
# not the locals() scope
exec(code_obj, globals())

# create/process Packet start/return the thread
# call the job_func so sys data can be captured
code_thread = KThread(target=self.python_job_func, args=(result_id,))
code_thread = KThread(target=self.python_job_func, args=(code, result_id,))
code_thread.start()

self.tasks[result_id]['task_thread'] = code_thread
self.tasks[result_id]["status"] = "running"

def python_job_func(self, result_id):
try:
buffer = StringIO()
sys.stdout = buffer
# now call the function required
# and capture the output via sys
method()
sys.stdout = sys.__stdout__
data_stats = buffer.getvalue()
result = self.packet_handler.build_response_packet(110, str(data_stats), result_id)
self.packet_handler.process_job_tasking(result)
self.tasks[result_id]["status"] = "completed"

except Exception as e:
p = "error executing specified Python job data: " + str(e)
result = self.packet_handler.build_response_packet(0, p, result_id)
self.packet_handler.process_job_tasking(result)
self.tasks[result_id]["status"] = "error"

def job_message_buffer(self, message):
# Supports job messages for checkin
try:
Expand Down Expand Up @@ -1097,7 +1049,7 @@ def process_packet(self, packet_type, data, result_id):
self.dynamic_code_execution_wait_save(data, result_id)

elif packet_type == 112:
self.disk_code_execution_wait_save(data, result_id)
self.start_python_job(data, result_id)

elif packet_type == 113:
self.start_python_job(data, result_id)
Expand Down
133 changes: 43 additions & 90 deletions empire/server/data/agent/ironpython_agent.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1007,10 +1007,9 @@ def dynamic_code_execute_wait_nosave(self, data, result_id):
"""
try:
buffer = StringIO()
sys.stdout = buffer
exec_globals = {**globals(), 'print': lambda *a, **k: print(*a, **k, file=buffer)}
code_obj = compile(data, "<string>", "exec")
exec(code_obj, globals())
sys.stdout = sys.__stdout__
exec(code_obj, exec_globals)
results = buffer.getvalue()
self.packet_handler.send_message(self.packet_handler.build_response_packet(110, str(results), result_id))
self.tasks[result_id]["status"] = "completed"
Expand All @@ -1034,10 +1033,9 @@ def dynamic_code_execution_wait_save(self, data, result_id):
data = data[20:]
try:
buffer = StringIO()
sys.stdout = buffer
code_obj = compile(data, "<string>", "exec")
exec(code_obj, globals())
sys.stdout = sys.__stdout__
exec_globals = {**globals(), 'print': lambda *a, **k: print(*a, **k, file=buffer)}
exec(code_obj, exec_globals)
results = buffer.getvalue().encode("latin-1")
c = compress()
start_crc32 = c.crc32_data(results)
Expand Down Expand Up @@ -1068,61 +1066,6 @@ def dynamic_code_execution_wait_save(self, data, result_id):
)
self.tasks[result_id]["status"] = "error"

def disk_code_execution_wait_save(self, data, result_id):
"""
Execute on-disk code and wait for the results while saving output.
Adjusted for Windows and cross-platform compatibility.
Task 112
"""
try:
script_globals = {}
output_capture = io.StringIO()
sys.stdout = output_capture

try:
exec(data, script_globals)
except SyntaxError as e:
result = "[!] Syntax error in script: %s on line %d - %s" % (str(e), e.lineno, e.text)
self.packet_handler.send_message(
self.packet_handler.build_response_packet(0, result, result_id)
)
self.tasks[result_id]["status"] = "error"
return

except Exception as e:
result = "[!] Error executing script: %s" % str(e)
self.packet_handler.send_message(
self.packet_handler.build_response_packet(0, result, result_id)
)
self.tasks[result_id]["status"] = "error"
return

captured_output = output_capture.getvalue()

if captured_output:
result = "[*] Output from script:\n" + captured_output
else:
result = "[*] No output captured from the script.\n"

if 'output' in script_globals:
result += "[*] Output variable from script: \n" + str(script_globals['output'])

self.packet_handler.send_message(
self.packet_handler.build_response_packet(112, result, result_id)
)
self.tasks[result_id]["status"] = "completed"

except Exception as e:
self.packet_handler.send_message(
self.packet_handler.build_response_packet(
0, "error executing TASK_PYTHON_CMD_JOB: %s" % (e), result_id
)
)
self.tasks[result_id]["status"] = "error"

finally:
sys.stdout = sys.__stdout__

def powershell_task(self, data, result_id):
"""
Execute a PowerShell command.
Expand Down Expand Up @@ -1224,43 +1167,53 @@ def powershell_task_dyanmic_code_wait_nosave(self, data, result_id):
)
self.tasks[result_id]["status"] = "error"

def start_python_job(self, code, result_id):
# create a new code block with a defined method name
code_block = "def method():\n" + indent(code)
def python_job_func(self, data, result_id):
"""
Execute python script, wait for the results and return stdout.
Adjusted for Windows and cross-platform compatibility.
Task 112
"""

output_capture = io.StringIO()
script_globals = {'print': lambda *a, **k: print(*a, **k, file=output_capture)}

# register the code block
code_obj = compile(code_block, "<string>", "exec")
# code needs to be in the global listing
# not the locals() scope
exec(code_obj, globals())
try:
exec(data, script_globals)
captured_output = output_capture.getvalue()
if captured_output:
result = "[*] Output from script:\n" + captured_output
else:
result = "[*] No output captured from the script.\n"
if 'output' in script_globals:
result += "[*] Output variable from script: \n" + str(script_globals['output'])
self.packet_handler.send_message(
self.packet_handler.build_response_packet(112, result, result_id)
)
self.tasks[result_id]["status"] = "completed"

except SyntaxError as e:
result = "[!] Syntax error in script: %s on line %d - %s" % (str(e), e.lineno, e.text)
self.packet_handler.send_message(
self.packet_handler.build_response_packet(0, result, result_id)
)
self.tasks[result_id]["status"] = "error"

except Exception as e:
result = "[!] Error executing script: %s" % str(e)
self.packet_handler.send_message(
self.packet_handler.build_response_packet(0, result, result_id)
)
self.tasks[result_id]["status"] = "error"

def start_python_job(self, code, result_id):
# create/process Packet start/return the thread
# call the job_func so sys data can be captured
code_thread = KThread(target=self.python_job_func, args=(result_id,))
code_thread = KThread(target=self.python_job_func, args=(code, result_id,))
code_thread.start()

self.tasks[result_id]['task_thread'] = code_thread
self.tasks[result_id]["status"] = "running"

def python_job_func(self, result_id):
try:
buffer = StringIO()
sys.stdout = buffer
# now call the function required
# and capture the output via sys
method()
sys.stdout = sys.__stdout__
data_stats = buffer.getvalue()
result = self.packet_handler.build_response_packet(110, str(data_stats), result_id)
self.packet_handler.process_job_tasking(result)
self.tasks[result_id]["status"] = "completed"

except Exception as e:
p = "error executing specified Python job data: " + str(e)
result = self.packet_handler.build_response_packet(0, p, result_id)
self.packet_handler.process_job_tasking(result)
self.tasks[result_id]["status"] = "error"

def job_message_buffer(self, message):
# Supports job messages for checkin
try:
Expand Down Expand Up @@ -1629,7 +1582,7 @@ def process_packet(self, packet_type, data, result_id):
self.dynamic_code_execution_wait_save(data, result_id)

elif packet_type == 112:
self.disk_code_execution_wait_save(data, result_id)
self.start_python_job(data, result_id)

elif packet_type == 113:
self.start_python_job(data, result_id)
Expand Down
3 changes: 0 additions & 3 deletions empire/server/data/agent/stagers/common/chacha.py
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Original file line number Diff line number Diff line change
Expand Up @@ -301,9 +301,6 @@ def process_tasking(self, data):

packetOffset += 12 + length

# send_message() is patched in from the listener module
self.send_message(resultPackets)

except Exception as e:
print(e)
pass
Expand Down