0eb5077551
Closes polling's blind spot (processes that exit between sweeps) with a real
eBPF probe and a declarative, data-driven detection engine — inspired by Snort
(rule language, signature IDs) and OSSEC (host-IDS framing).
New events/ subpackage:
- bcc_source.py : eBPF C tracing execve (filename, argv[1..2], ppid, uid,
parent comm) over a perf buffer, loaded via bcc; lazy import
+ available()/try-except so it fails closed to poll-only when
bcc/root/BTF are absent — a broken probe never downs the daemon
- exec_event.py : the ExecEvent type
- rules.py : ExecRule (sid/msg/severity/classtype + path/exec/parent/argv
conditions) and ExecRuleEngine; 4 shipped rules (fileless exec
100001, reverse-shell argv 100002, web/DB→shell RCE 100003,
curl|sh 100004); operators add more via exec_rules_file TOML
- monitor.py : runs the source on a thread, routes events through the engine
Integration:
- daemon starts the monitor, shares a lock-guarded cooldown with the sweep
loop, and feeds event alerts into the same snapshot pipeline
- Alert gains Snort-style sid + classtype; retrofitted onto all 7 poll
detectors; snapshots and JSON now carry them
- config: ebpf_exec_monitor (default on, degrades), exec_rules_file
- systemd: opt-in ebpf.conf drop-in (relaxes MemoryDenyWriteExecute + widens
caps for bcc's JIT) so the base unit stays hardened for poll-only
- sentinel-redteam: ebpf_exec drill (short-lived /tmp exec + /dev/tcp argv the
poller can't see); footer now uses the Python CLI
Tests: +14 cases for the rule engine (each default rule match/non-match, rule
validation, parent-exclude). 39/39 pass. Graceful non-root degradation verified.
NOTE: the eBPF C follows bcc's execsnoop pattern but could not be run here
(BPF needs root); it wants a root smoke-test on a real host.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
43 lines
1.3 KiB
Python
43 lines
1.3 KiB
Python
# SPDX-License-Identifier: GPL-3.0-or-later
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"""The execve event — one process-execution observed by the kernel probe."""
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from __future__ import annotations
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import os
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from dataclasses import dataclass, field
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@dataclass(frozen=True)
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class ExecEvent:
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"""A single ``execve``, as seen at the moment of execution.
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Captured by the eBPF probe (so it exists even for processes that exit before
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a poll). ``parent_comm`` is the caller; ``filename`` is the program being
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executed; ``argv`` is as much of the argument vector as the probe captured.
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"""
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pid: int
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ppid: int
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uid: int
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parent_comm: str
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filename: str
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argv: tuple[str, ...] = field(default_factory=tuple)
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@property
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def exec_comm(self) -> str:
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"""Basename of the executed program (its post-exec ``comm``)."""
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return os.path.basename(self.filename)
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@property
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def argv_str(self) -> str:
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"""Full command line for regex matching (filename + captured args)."""
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return " ".join((self.filename, *self.argv)).strip()
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def to_dict(self) -> dict:
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return {
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"pid": self.pid,
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"ppid": self.ppid,
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"uid": self.uid,
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"parent_comm": self.parent_comm,
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"filename": self.filename,
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"argv": list(self.argv),
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}
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