2017-05-17 12:49 AM
Hi,
We have integrated Windows Event logging via Snare. We have noticed that the log size is quite huge per log. After extracting the events from SA, we noticed the below:-
Apr 27 13:23:59 <HOST> MSWinEventLog,1,Security,39637953,Thu Apr 27 13:23:59 2017,4624,Microsoft-Windows-Security-Auditing,<USER>,N/A,Success Audit,<HOST>,Logon,,An account was successfully logged on. Subject: Security ID: <SID> Account Name: <HOST> Account Domain: <DOMAN>Logon ID: 0x7 Logon Type: 3 New Logon: Security ID: <SID> Account Name: <USER>Account Domain: <DOMAIN> Logon ID: <ID>Logon GUID: {<GUID>} Process Information: Process ID: 0x1c10 Process Name: C:\Windows\System32\inetsrv\w3wp.exe Network Information: Workstation Name: <HOST>Source Network Address: - Source Port: - Detailed Authentication Information: Logon Process: Authz Authentication Package: Kerberos Transited Services: - Package Name (NTLM only): - Key Length: 0 This event is generated when a logon session is created. It is generated on the computer that was accessed. The subject fields indicate the account on the local system which requested the logon. This is most commonly a service such as the Server service, or a local process such as Winlogon.exe or Services.exe. The logon type field indicates the kind of logon that occurred. The most common types are 2 (interactive) and 3 (network). The New Logon fields indicate the account for whom the new logon was created, i.e. the account that was logged on. The network fields indicate where a remote logon request originated. Workstation name is not always available and may be left blank in some cases. The authentication information fields provide detailed information about this specific logon request. - Logon GUID is a unique identifier that can be used to correlate this event with a KDC event. - Transited services indicate which intermediate services have participated in this logon request. - Package name indicates which sub-protocol was used among the NTLM protocols. - Key length indicates the length of the generated session key. This will be 0 if no session key was requested.,39631153
The section marked in red, is just explaining the reason the event was generated.
Is there a way we can remove this extra text. I know my current available solutions are:-
- Don't use Snare and use WinRM
- Write my own parser for Windows Events
Our current project timelines do not allow for the above solutions, just wondering if there was an alternate
Thanks,
Jeremy,
2017-05-18 07:00 AM
Hi Jeremy,
Microsoft has introduced the descriptive event data for each log event to keep aware of customers to be aware of the reason for log event generated. I agree that descriptive text for each log event is redundant which causes to use high SIEM storage and network bandwidth.
"Truncating the repetitive descriptive text which is not used for forensic analysis" is the best solution which was documented in Snare as below.
Video:https://www.intersectalliance.com/wp-content/uploads/vids/WindowsTruncation.mp4
Document: How Windows Truncation can save up to 75% on network bandwidth and SIEM disk space - Snare
2017-05-18 07:00 AM
Hi Jeremy,
Microsoft has introduced the descriptive event data for each log event to keep aware of customers to be aware of the reason for log event generated. I agree that descriptive text for each log event is redundant which causes to use high SIEM storage and network bandwidth.
"Truncating the repetitive descriptive text which is not used for forensic analysis" is the best solution which was documented in Snare as below.
Video:https://www.intersectalliance.com/wp-content/uploads/vids/WindowsTruncation.mp4
Document: How Windows Truncation can save up to 75% on network bandwidth and SIEM disk space - Snare
2017-06-07 12:15 AM
Thanks Sravan, Tested this and its working.
Could you confirm that there is no parsing issue once we do this?
Thanks
Jeremy.
2017-06-07 12:21 AM
Hi Jeremy,
I am glad to hear that solution works. As logs will be truncating tail part and not touching the header part, it shouldn't cause parsing issues.
Thanks,
Sravan