28d67a1360
Port the bash prototype to a structured, testable Python codebase while
preserving the same control loop and the seven detection signatures. The bash
implementation stays in src/ as the regression oracle.
Highlights:
- enodia_sentinel/ package (stdlib only — no runtime deps):
- detectors/ : one pure function per signature, detect(state, cfg)->Alerts
- system.py : SystemState — one cached /proc + ss snapshot per sweep,
fully injectable so detectors are unit-testable
- daemon.py : sweep loop, in-process cooldown dedup, threaded snapshot
capture, and a SUID filesystem scan moved OFF the loop
thread onto a slow background cadence
- snapshot.py: forensic text + JSON sidecar with per-signature IR guidance
- config.py : dataclass config via TOML + env overrides
- netutil.py : public-IP / CIDR logic via stdlib ipaddress
- tests/ : 25 stdlib-unittest cases (no root, no /proc, no ss needed)
- TOML config, launcher wrapper, Makefile (pip-free install), hardened
systemd unit (env-resolved ExecStart), updated PKGBUILD, rewritten README
Performance: per-sweep cost ~200 ms (shared cached state); the multi-second
SUID walk no longer blocks detection. scandir-based walk replaces os.walk.
Verified on Arch: all 7 detectors fire on red-team drills (reverse_shell,
ld_preload, deleted_exe, new_listener, new_suid confirmed live end-to-end),
no false positives on a clean sweep, 25/25 tests pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
46 lines
1.5 KiB
Python
46 lines
1.5 KiB
Python
"""ld_preload — userland rootkit / library-injection indicators.
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Two signatures:
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* ``/etc/ld.so.preload`` non-empty: injects into *every* dynamically-linked
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process — the classic system-wide rootkit hook.
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* a process whose ``LD_PRELOAD`` points into a writable/temp dir — per-process
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function hooking (hiding files/procs, stealing credentials).
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"""
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from __future__ import annotations
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from collections.abc import Iterator
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from pathlib import Path
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from ..alert import Alert, Severity
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from ..config import Config
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from ..system import SystemState
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_SUSPICIOUS_PREFIXES = ("/tmp/", "/dev/shm/", "/var/tmp/", "/run/user/", "./")
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def detect(state: SystemState, cfg: Config) -> Iterator[Alert]:
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preload = Path("/etc/ld.so.preload")
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try:
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contents = preload.read_text().strip() if preload.is_file() else ""
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except OSError:
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contents = ""
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if contents:
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yield Alert(
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severity=Severity.CRITICAL,
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signature="ld_preload",
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key="ldp:global",
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detail=f"/etc/ld.so.preload is non-empty: [{contents.replace(chr(10), ' ')}]",
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)
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for proc in state.processes:
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pre = proc.environ.get("LD_PRELOAD", "")
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if not pre:
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continue
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if pre.startswith(_SUSPICIOUS_PREFIXES):
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yield Alert(
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severity=Severity.CRITICAL,
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signature="ld_preload",
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key=f"ldp:{proc.pid}",
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detail=f"pid={proc.pid} comm={proc.comm} LD_PRELOAD=[{pre}]",
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pids=(proc.pid,),
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)
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