Individual skill

detecting-beaconing-patterns-with-zeek

Performs statistical analysis of Zeek conn.log connection intervals to detect C2 beaconing patterns. Uses the ZAT library to load Zeek logs into Pandas DataFrames, calculates inter-arrival time standard deviation, and flags periodic connections with low jitter. Use when hunting for command-and-control callbacks in network data.

internal/tools/skills/data/security-operations/detecting-beaconing-patterns-with-zeek/SKILL.md

Read pinned source

Source commit d42f381ad34843e71a42658e5c57290c713e85af

What was checked

Matches the observed repository HEAD
Yes
Scanner rules are current
Yes
Repository scan complete
No
Skill scan complete
No
Observed behavior
Instructions only
Last checked
Nov 9, 2026

These are observations at the recorded commit, not a guarantee of safety. Review the source before running it.

Install this skill

Choose an agent in your Stack or copy a command below. Commands fetch the pinned commit and copy only this skill directory. Existing destinations are refused. Copying a command does not install anything.

An install command is unavailable: current rules, complete repository and skill scans, an eligible behavior level and a permitted license are required.

Repository context

Repository stars (not skill ratings)
1,325
Repository last updated
Nov 9, 2026
License
Apache-2.0

Observed agent integration: No specific integration evidence. Standard SKILL.md installation does not imply verified compatibility.

Files and excerpt

File metadata and permitted, redacted excerpts come from the recorded scan. Source links are pinned to that commit.

Browse files
Read excerpt

# Detecting Beaconing Patterns with Zeek


## When to Use

- When investigating security incidents that require detecting beaconing patterns with zeek
- When building detection rules or threat hunting queries for this domain
- When SOC analysts need structured procedures for this analysis type
- When validating security monitoring coverage for related attack techniques

## Detection Gaps & Validation

- **Jitter defeats low-std-dev rules:** modern C2 (Cobalt Strike `jitter`, Sliver, malleable profiles) randomizes sleep ±20–50%, inflating the standard deviation so a raw `std_dev`-only test misses it. Use the coefficient of variation (CV = std/mean) and also bucket inter-arrival times into a histogram / FFT to find a dominant period despite jitter; flag CV below ~0.1–0.3 rather than near-zero.
- **Too few samples = false negative:** the `len(intervals) > 10` gate silently skips slow beacons (hourly/daily callbacks) over short capture windows. Beaconing detection needs long-haul conn.log data (24h+); state the window and don't treat short captures as clean.
Back to top