microsoft / microsoft/SysmonForLinux

sysmon 1.4.0 missing TCP events on RHEL 9

Open
#218 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Dominant language
C
Stars
2.2k
Forks
220
Avg merge
11d 22h
Merged PRs (30d)
2

Description

Issue:
I have Sysmon installed on a RHEL 9 server and it is failing to log any TCP events. UDP events log fine. I am testing with a wide open sysmon config (attached). I've tested the same configuration on Ubuntu 24.04.3 LTS with no issues.

I have attached the output of a tracepoint test that I ran, the shell script used, and also the perf list output showing sysmon attached to inet_sock_set_state.

sysmon.xml

tracepoint_test.sh

tracepoint_test_output.txt

perf_list.txt

Sysmon Version
1.4.0

OS/kernel version
RHEL 9.6 (Plow)
5.14.0-611.9.1.el9_7.x86_64

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with tracepoint_test.sh and tracepoint_test_output.txt, then compare the RHEL 9 results with perf_list.txt and the reported Ubuntu behavior. Reproduce the missing TCP events with sysmon.xml on the stated RHEL kernel; done means TCP events are logged while UDP events continue to work.

Written by the indexing model from the issue text.

Assessment

Tech stack
linux
Domain
networking, operating-systems
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.