Mind the Log

🧩 CEF, But Not Quite: UniFi OS Events Break the Format TL;DR: UniFi devices generate two types of CEF events—one from "UniFi Network" and one from "UniFi OS". Only the "UniFi Network" events are properly formatted. "UniFi OS" events are malformed, missing required fields, and cannot be parsed without custom workarounds. If you're relying on CEF parsers, expect frustration. Ubiquiti should fix these broken events. In my previous post, I wrote that UniFi devices can generate CEF events for both UniFi OS and UniFi Network . I need to clarify that statement. Because only one of those event types is correctly formatted as CEF. The other? Parsers won’t even touch it. What CEF is supposed to look like To make sense of this, let’s first recap what a CEF event is supposed to look like. The official documentation for the format is here: 👉 Micro Focus CEF Implementation Standard According to the spec, a typical CEF header looks l...

TL;DR: UniFi devices generate CEF events with inconsistent timestamp formats depending on where you enable activity logging. - CEF events from "UniFi Network" use UTC timestamps. - CEF events from "UniFi OS" use local time (without time zone info). - Non-CEF events also use local time . If you're parsing logs or building integrations, this inconsistency matters. Dear Ubiquiti: pick one. In my previous post, I wrote that CEF event timestamps from UniFi devices use the UTC time zone. After digging deeper, I need to clarify that statement. And in doing so, I'm documenting yet another inconsistency in how UniFi logs work. But first, let's take a quick look at what a CEF event is supposed to look like—and while we're at it, a brief CEF history lesson. The Common Event Format (CEF) was created by ArcSight, one of the early SIEM vendors. ArcSight was later acquired by HP, and eventually ended up at Micro Focus. You can find the official CEF...

TL;DR: UniFi logs from different processes don't use a consistent time zone. CEF events are timestamped in UTC, while other logs use the local device time (which may include daylight savings). This inconsistency causes confusion and breaks correlation in SIEMs and log management systems. Ubiquiti should standardise on UTC for all events. Looking at the logs from my UniFi Dream Machine Pro, it's clear that many different processes are responsible for providing all the awesome functionality it offers. In my previous post, I pointed out that, in this day and age, timestamps should include time zone information . But at the very least, you'd expect that all processes on the same device use the same time zone, right? Nope. Take a look at this screenshot from my log management system: First, you see an ingesttimestamp —the time when the log management system received the event. Then you see the raw event as sent by the UniFi Dream Machine. Look at the highlighte...

TL;DR: UniFi's syslog output still uses an outdated timestamp format that lacks time zone information. That's a problem for SIEMs and log management systems where correlation and accurate timelines matter. Modern formats like the one defined in RFC 5424 include time zone data—UniFi should adopt this. The logs from UniFi devices have historically been somewhat underwhelming—especially when it comes to integration with SIEMs and log management systems. But with version 8.5.6 of the UniFi Network Application, released in October 2024 , there was a welcome change: "Export all or specific System Logs shown on the Network Application to SIEM Servers (remote Syslog) such as Splunk, Microsoft Sentinel, IBM QRadar, and others." — Release notes for UniFi Network Application 8.5.6 I was genuinely excited to see this. At last, logs from UniFi devices were getting some SIEM love! 🕓 Time Stamps: The Basics Logs are chronological records of system activity. Ea...

TL;DR: UniFi Teleport VPN logs (in CEF format) are missing the client's remote IP address—the WireGuard endpoint—which is critical for threat detection, auditing, and correlation in SIEM tools. Although this IP is available in other events, it isn't included in the CEF event. Adding a field like UNIFIvpnClientRemoteIp would significantly improve log completeness and security monitoring value. When a Teleport VPN connection is made through a UniFi device, three IP addresses are involved: The remote IP of the Teleport client (the WireGuard endpoint) The WAN IP of the UniFi device The internal IP assigned to the Teleport client The CEF log that's generated captures a good deal of useful information, including the internal client IP, VPN type, and WAN interface. But one important piece is missing: the remote IP address of the Teleport client. Here's an example CEF event for a VPN connection: CEF:0|Ubiquiti|UniFi Network|9.3.45|522|Teleport Clie...

 UniFi makes some great hardware for prosumers—and their software has come a long way. But if you've ever tried to work with the logs, especially in a security or observability context, you'll know: it's not all sunshine and structured data. This blog is my attempt to document what is logged, what isn't, and what I think should be. It's not about bashing Ubiquiti. I use their gear, and I want it to get better. But logs matter—especially when you're trying to detect threats, troubleshoot issues, or feed data into a SIEM. I'll be writing about missing fields in CEF messages, odd behaviors in syslog output, inconsistent timestamps, and anything else that pops up. This blog is meant to be technical, opinionated, and (hopefully) helpful. If you care about logging, observability, or just making the most of your UniFi gear, stick around. — Mind the Log