https://blog.efespain.com/en/tags/botnet/A honeypot in some corner of the network. Every infection, a story worth telling.HugoeneFeSpaineFeSpain2026 eFeSpainTue, 01 Sep 2026 12:00:00 +0000https://blog.efespain.com/en/chapter-27/Tue, 01 Sep 2026 12:00:00 +0000https://blog.efespain.com/en/chapter-27/The kit sat still on the disk, so I switched it on myself in a cage with no way out. Inside there's a bot that insists on knowing its own address before anything else, joins a mesh of up to two thousand nodes, holds an election and crowns itself leader — and only then opens a Telegram chat. The operator never logs into any machine: he sends a message to the head of the pack. And when you burn the chat, the botnet heals itself.https://blog.efespain.com/en/chapter-26/Tue, 01 Sep 2026 12:00:00 +0000https://blog.efespain.com/en/chapter-26/The family from the previous chapter didn't stand still: there's a newer build going around, and I caught it from the first second. It brute-forces its way in over SSH, sizes the machine up, evicts the competition —its own older version included—, uploads sixteen megabytes in a single file and fires. All in a little over a minute. And then it walks straight into one line of fstab.https://blog.efespain.com/en/chapter-22/Tue, 01 Sep 2026 12:00:00 +0000https://blog.efespain.com/en/chapter-22/A bot of the Mirai school carries the address of whoever gives it orders. I looked for this one's by four different routes and found it by none — and along the way I published a theory of my own that turned out to be false. What finally worked wasn't a better tool: it was realising that somewhere out there sat another binary, compiled from the same code, whose command centre somebody had already published. With both in front of me, the difference between them is one thousand one hundred and thirty bytes.https://blog.efespain.com/en/chapter-21/Tue, 01 Sep 2026 12:00:00 +0000https://blog.efespain.com/en/chapter-21/An automated scanner found the honeypot's telnet and, eighteen seconds later, there was a binary inside. The password was «telnet». The loader it dropped comes with two operator typos, one of which breaks an entire infection. And when I finally put a name to the family —IranBot, a Mirai fork with a public dossier— it turned out that name had been written on this blog since August: a rival bot had put it there, in the list of competitors it uninstalls on arrival.https://blog.efespain.com/en/chapter-18/Tue, 01 Sep 2026 12:00:00 +0000https://blog.efespain.com/en/chapter-18/An already-infected IP connected to the honeypot's telnet and pasted a recipe all at once: eleven binaries, one per architecture, each with a made-up name that will never come round again. Two weighed exactly the same and looked like variants — they turned out to be the i586 and i686 builds of the same program. And behind them wasn't a stray bug: fifty-odd distinct binaries in two weeks. The whole delivery is built so that no blocklist, by name or by signature, catches anything.https://blog.efespain.com/en/chapter-17/Sat, 01 Aug 2026 12:00:00 +0000https://blog.efespain.com/en/chapter-17/A quiet Sunday, my new-binary alarm went off after days of silence. The first thought was the best one there is: something fresh. What followed was a rollercoaster — an old acquaintance, a false positive that nearly fooled me, and finally a critter that wasn't in any public repository, caught less than thirty hours after it was born.https://blog.efespain.com/en/chapter-16/Sat, 01 Aug 2026 12:00:00 +0000https://blog.efespain.com/en/chapter-16/A bot walked into my honeypot, stayed 62 seconds and left. I filed it as Gafgyt and I was wrong. A week later I followed its command servers and ended up inside an operation that has been running since 2015 — one I'd had in my hands from day one.https://blog.efespain.com/en/chapter-11/Sat, 01 Aug 2026 12:00:00 +0000https://blog.efespain.com/en/chapter-11/A 1,177-byte loader landed: nine lines of wget, one per architecture, in the style I have already opened three times on this blog. I was going to file it as a repeat offender and get on with my day. I opened it anyway, out of habit — and the first thing I saw was that it had a few characters too many.