Something I’ve found useful when analyzing a Windows host is a record of what processes executed. If you’ve ever looked in Event Viewer, you’ll know that by default, they look like this:

(This space intentionally left blank.)

So, let’s turn process auditing on.  Enable auditing for “Audit Process Creation” and “Audit Process Termination”.

Now, anytime a process is created or terminated, you’ll get a log similar to the following:

A new process has been created.

Subject:
Security ID: [domain]/[user]
Account Name: [user]
Account Domain: [domain]
Logon ID: 0x9cb68

Process Information:
New Process ID: 0x18f8
New Process Name: C:\Windows\System32\mspaint.exe
Token Elevation Type: TokenElevationTypeDefault (1)
Creator Process ID: 0x1084

Token Elevation Type indicates the type of token that was assigned to the new process in accordance with User Account Control policy.

Type 1 is a full token with no privileges removed or groups disabled. A full token is only used if User Account Control is disabled or if the user is the built-in Administrator account or a service account.

Type 2 is an elevated token with no privileges removed or groups disabled. An elevated token is used when User Account Control is enabled and the user chooses to start the program using Run as administrator. An elevated token is also used when an application is configured to always require administrative privilege or to always require maximum privilege, and the user is a member of the Administrators group.

Type 3 is a limited token with administrative privileges removed and administrative groups disabled. The limited token is used when User Account Control is enabled, the application does not require administrative privilege, and the user does not choose to start the program using Run as administrator.

That’s an OK log, we know what executed and when, and could trace back the “Creator Process ID” to find the creating process. However, the log is rather long and contains quite a bit of useless information; this will chew up your Splunk (or other log aggregation tool) license in no time.

WLS can help us here. It will create key / value pairs from the log, add useful information, and not fill your logs with paragraphs of redundant information. The example below uses my default metadata settings for WLS, the bold text indicates the extra information WLS added to the log.

Mar 21 12:45:26 [host] Security: LogType=”WLS”, BaseFileName=”mspaint.exe”, Cached=”True”, Channel=”Security”, CommandLine=”‘C:\windows\system32\mspaint.exe’ ‘C:\Users\[user]\Desktop\blog\TurnAuditingOn.png'”, CompanyName=”Microsoft Corporation”, Computer=”[host].[domain]”, CreatorProcessName=”explorer”, Entropy=”6.17942325269204″, EventID=”4688″, EventRecordID=”1145730″, ExecutionProcessID=”4″, ExecutionThreadID=”48″, FileDescription=”Paint”, FileVersion=”6.1.7600.16385 (win7_rtm.090713-1255)”, InternalName=”MSPAINT”, Keywords=”0x8020000000000000″, Language=”English (United States)”, Length=”6676480″, Level=”0″, MD5=”458F4590F80563EB2A0A72709BFC2BD9″, NewProcessId=”0x18f8″, NewProcessName=”C:\Windows\System32\mspaint.exe”, Opcode=”0″, ProcessId=”0x1084″, ProductVersion=”6.1.7600.16385″, ProviderGuid=”{54849625-5478-4994-A5BA-3E3B0328C30D}”, ProviderName=”Microsoft-Windows-Security-Auditing”, SHA1=”3F97DC3BD1467C710C6A8D26B97BB6CF47DEB4C6″, Signed=”False”, SubjectDomainName=”[domain]”, SubjectLogonId=”0x9cb68″, SubjectUserName=”[user]”, SubjectUserSid=”[sid]”, Task=”13312″, TokenElevationType=”%%1936″, Version=”0″, Zone=”0″

The standard windows log is 1,353 characters, the WLS log is 1,141 (with pretty much every optional data point added). Less data, higher quality, useful stuff. Now, what to do with all the data…