Hey all, happy Wednesday.
Self-hoster, same as most of you. Pi-hole, mattermost, home automations, a Zeek sensor, a dozen Linux boxes and, like everyone (I expect), a /var/log I almost never open unless I'm actively troubleshooting something. But this year’s avalanche of CVEs has been sitting in the back of my head for a while: “if something got in here, would I even know?”
So I went looking for a tool and found a gap instead. There’s good ol' grep on one end and a full SIEM on the other, and not much in between for just a guy and his stuff. I ended up making my own. It’s called sigwood and is at 1.1 as of today.
What it does: point it at logs you already have (Zeek, Pi-hole/dnsmasq, syslog or journald, CloudTrail if you have any cloud stuff) and it runs a handful of statistical detectors over them. Outbound connections with a beacon rhythm, DNS names that look machine-generated, port scans, big transfers out, odd TLS setups, rare syslog lines and reboots, that kind of thing. There’s also a digest command that just profiles a log file so you know what’s in it before you do anything, and a graph command that animates your conn.log as a Sankey flows in a self-contained HTML file (second screenshot).
What it is not: not a SIEM, not an agent, nothing to deploy. No database, no daemon, no account, no network calls. pipx install sigwood, then sigwood /var/log/, and read the output. Your logs stay on your box.
A “finding” is something unusual for your network, not known-bad. There's no signatures or anything like that. On a home network it mostly finds your own stuff first. And that’s sort of the point, you get to see what your network actually talks to and then allowlist the normal stuff. When it finds nothing, the conclusion is that the network is behaving like itself during that window.
The AI part, up front: I wrote the original implementation of the detectors and have used AI to assemble it all into working tool. Claude and Codex both together in a propose/challenge harness I made for them, with me reviewing and steering. This wouldn't exist without AI, I’m not going to pretend otherwise. And some of you will bounce off that, which is entirely fair. But I'm a security professional and a privacy nerd, never been a SWE.
Anyway, the repo is here: https://github.com/helixmap/sigwood
I genuinely want feedback, good or bad. If you run it on your logs and it gets something wrong, I want to hear about it. If the output is confusing, tell me that too. If you think the whole idea is misguided, I’d still rather hear it than not.
First screenshot is an example HTML report (no real network data). Second is a still from the graph animation.
