mirror of https://github.com/sqall01/LSMS.git
124 lines
3.3 KiB
Python
Executable File
124 lines
3.3 KiB
Python
Executable File
#!/usr/bin/env python3
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# written by sqall
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# twitter: https://twitter.com/sqall01
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# blog: https://h4des.org
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# github: https://github.com/sqall01
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#
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# Licensed under the MIT License.
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"""
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Short summary:
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Monitor /etc/ld.so.preload for changes to detect malicious attempts to alter the control flow of binaries.
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NOTE: The first execution of this script should be done with the argument "--init".
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Otherwise, the script will only show you the current state of the environment since no state was established yet.
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However, this assumes that the system is uncompromised during the initial execution.
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Hence, if you are unsure this is the case you should verify the current state
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before monitoring for changes will become an effective security measure.
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Requirements:
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None
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"""
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import os
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import sys
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from typing import Set
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import lib.global_vars
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from lib.state import load_state, store_state
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from lib.util import output_error, output_finding
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# Read configuration.
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try:
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from config.config import ALERTR_FIFO, FROM_ADDR, TO_ADDR, STATE_DIR
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from config.monitor_ld_preload import ACTIVATED
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STATE_DIR = os.path.join(os.path.dirname(__file__), STATE_DIR, os.path.basename(__file__))
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except:
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ALERTR_FIFO = None
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FROM_ADDR = None
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TO_ADDR = None
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ACTIVATED = True
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STATE_DIR = os.path.join("/tmp", os.path.basename(__file__))
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def _get_ld_preload() -> Set[str]:
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path = "/etc/ld.so.preload"
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ld_data = set()
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if os.path.isfile(path):
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with open(path, 'rt') as fp:
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for line in fp:
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if line.strip() == "":
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continue
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ld_data.add(line.strip())
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return ld_data
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def monitor_ld_preload():
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# Decide where to output results.
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print_output = False
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if ALERTR_FIFO is None and FROM_ADDR is None and TO_ADDR is None:
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print_output = True
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if not ACTIVATED:
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if print_output:
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print("Module deactivated.")
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return
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stored_ld_data = set()
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try:
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state_data = load_state(STATE_DIR)
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# Convert list to set.
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if "ld_data" in state_data.keys():
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stored_ld_data = set(state_data["ld_data"])
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except Exception as e:
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output_error(__file__, str(e))
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return
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curr_ld_data = set()
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try:
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curr_ld_data = _get_ld_preload()
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except Exception as e:
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output_error(__file__, str(e))
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return
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# Compare stored data with current one.
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for stored_entry in stored_ld_data:
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if stored_entry not in curr_ld_data:
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message = "LD_PRELOAD entry '%s' was deleted." % stored_entry
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output_finding(__file__, message)
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continue
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# Check new data was added.
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for curr_entry in curr_ld_data:
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if curr_entry not in stored_ld_data:
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message = "LD_PRELOAD entry '%s' was added." % curr_entry
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output_finding(__file__, message)
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try:
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# Convert set to list.
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state_data = {"ld_data": list(curr_ld_data)}
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store_state(STATE_DIR, state_data)
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except Exception as e:
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output_error(__file__, str(e))
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if __name__ == '__main__':
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if len(sys.argv) == 2:
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# Suppress output in our initial execution to establish a state.
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if sys.argv[1] == "--init":
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lib.global_vars.SUPPRESS_OUTPUT = True
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monitor_ld_preload()
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