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>
Replace MIT with the full GNU GPLv3 text, update license metadata in
pyproject.toml (+ trove classifiers) and PKGBUILD, and add
SPDX-License-Identifier headers to all Python modules and shell scripts.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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>
Poll-based host intrusion-detection daemon modeled on freeze-watcher's
sample→trigger→snapshot→classify loop, with security signatures instead
of performance ones:
- reverse_shell (interpreter with a network socket on stdio)
- ld_preload (/etc/ld.so.preload or LD_PRELOAD in writable dirs)
- deleted_exe (process running from a deleted/memfd binary)
- new_listener (listening port absent from startup baseline)
- new_suid (new SUID/SGID binary; critical in writable dirs)
- persistence (cron/systemd/authorized_keys/rc-file changes)
- suspicious_egress (interpreter holding an outbound public connection)
Each capture writes a forensic snapshot with per-signature incident-
response guidance. Includes a safe, self-cleaning red-team harness
(sentinel-redteam), hardened systemd unit, config, Makefile, and Arch
packaging.
Tested on Arch: detectors fire on drills, no false positives on a clean
sweep, sweep cost optimized from ~15s to ~1s via batched syscalls and a
gated filesystem-wide SUID scan.
This bash implementation is retained as the regression oracle for the
forthcoming Python rewrite.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
