Filtering streams

Graylog Central (peer support)
1

Hi, i just installed Graylog. Everything is fine, but… i have to much logs :slight_smile: Please, help me with filtering.

I have stream accepting windows event logs - gelf.
I am monitoring for example EventID : 4624 (log in). But this event generates not only logs from people but from server or system. A want to delete this message. So i created pipeline and apply to that stream:

Problem is, that i am still receiving unwanted messages as below. Am i doing something wrong?
Thanks
Lucas

rule “Drop unnecessary messages”
when
has_field(“TargetUserName”) AND
(
contains(to_string($message.TargetUserName),“ABRA”) OR
contains(to_string($message.TargetUserName),“DWM”) OR
contains(to_string($message.TargetUserName),“SYSTEM”)
)
then
drop_message();
end

ALLERT CONFIGURATION:

Source : {message.fields.source} TargetUserName : {message.fields.TargetUserName}
EventID : {message.fields.EventID} IpAddress : {message.fields.IpAddress}
Channel : {message.fields.Channel} Category : {message.fields.Category}
Severity : {message.fields.Severity} Message : {message.fields.message}

RESULT IN MAIL:
as you can see, there is ABRA what should be deleted

Source : abra.codya.local
TargetUserName : ABRA$
EventID : 4624
IpAddress : ::1
Channel : Security
Category : Logon
Severity : INFO
Message : An account was successfully logged on.

Subject:
Security ID

2

what version of Graylog are you using ? Please try using stream rules, as an alternative.

3

@Assembler
You can use more then one rule to filter down to the messages you want, since you using GELF I sure you have multiple fields you can use. Here is an example:
Must match all of the 3 configured stream rules.

image
image1857×235 22.2 KB

Hope that helps.

4

Hi,
I am using version: v3.0.2+1686930.

There is problem with stream rules. Now i have ONE stream WindowsEvents. IF i separate it to two streams. WindowsEvents and event 4624.

Stream WindowsEvets
must be filtered
event != 4624

Stream 4624
must be filtered
event = 4624 and (username != “system” OR username != “servername”)

How you will do it? Can be done by regular expression? I dont know. May be yes, but for me it is to dificult. Pipelines seems easer. But… I dont now why it is not working. May be something is missing.

Thanks
L.

5

I have some update. I tryed this:

rule “Drop unnecessary messages”
when
has_field(“TargetUserName”)
then
set_field(“TargetUserName”, “123456789”);
end

and TargetUserName was not changed. So there is something else wrong…

6

I found solution myself: Must be applied to all messages

rule “Drop unnecessary messages”
when
has_field(“SourceModuleName”) AND
to_string($message.SourceModuleName) == “eventlog” AND
has_field(“TargetUserName”) AND
(
to_string($message.TargetUserName) == “SYSTEM” OR
to_string(message.TargetUserName) == "ABRA" OR
contains(to_string($message.TargetUserName),“DWM”)
)
then
drop_message();
end