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[Rule Tuning] Suspicious Process Creation CallTrace (#2207)

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Excluding some FPs by process.parent.executable and process.parent.args.
This commit is contained in:
Samirbous
2022-08-01 19:00:13 +02:00
committed by GitHub
parent 1f21c5c57f
commit 04dcf09c03
1 changed files with 16 additions and 5 deletions
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rules/windows/defense_evasion_suspicious_process_creation_calltrace.toml
+16 -5
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@@ -1,7 +1,7 @@
[metadata]
creation_date = "2021/10/24"
maturity = "production"
updated_date = "2022/03/31"
updated_date = "2022/08/01"
[rule]
author = ["Elastic"]
@@ -24,10 +24,21 @@ query = '''
sequence by host.id with maxspan=1m
[process where event.code == "1" and
/* sysmon process creation */
process.parent.name : ("winword.exe", "excel.exe", "outlook.exe", "powerpnt.exe", "eqnedt32.exe",
"fltldr.exe", "mspub.exe", "msaccess.exe", "powershell.exe", "pwsh.exe",
"cscript.exe", "wscript.exe", "rundll32.exe", "regsvr32.exe", "mshta.exe",
"wmic.exe", "cmstp.exe", "msxsl.exe")] by process.parent.entity_id, process.entity_id
process.parent.name : ("winword.exe", "excel.exe", "outlook.exe", "powerpnt.exe", "eqnedt32.exe", "fltldr.exe",
"mspub.exe", "msaccess.exe","cscript.exe", "wscript.exe", "rundll32.exe", "regsvr32.exe",
"mshta.exe", "wmic.exe", "cmstp.exe", "msxsl.exe") and
/* noisy FP patterns */
not (process.parent.name : "EXCEL.EXE" and process.executable : "?:\\Program Files\\Microsoft Office\\root\\Office*\\ADDINS\\*.exe") and
not (process.executable : "?:\\Windows\\splwow64.exe" and process.args in ("8192", "12288") and process.parent.name : ("winword.exe", "excel.exe", "outlook.exe", "powerpnt.exe")) and
not (process.parent.name : "rundll32.exe" and process.parent.args : ("?:\\WINDOWS\\Installer\\MSI*.tmp,zzzzInvokeManagedCustomActionOutOfProc", "--no-sandbox")) and
not (process.executable :
("?:\\Program Files (x86)\\Microsoft\\EdgeWebView\\Application\\*\\msedgewebview2.exe",
"?:\\Program Files\\Adobe\\Acrobat DC\\Acrobat\\Acrobat.exe",
"?:\\Windows\\SysWOW64\\DWWIN.EXE") and
process.parent.name : ("winword.exe", "excel.exe", "outlook.exe", "powerpnt.exe")) and
not (process.parent.name : "regsvr32.exe" and process.parent.args : ("?:\\Program Files\\*", "?:\\Program Files (x86)\\*"))
] by process.parent.entity_id, process.entity_id
[process where event.code == "10" and
/* Sysmon process access event from unknown module */
winlog.event_data.CallTrace : "*UNKNOWN*"] by process.entity_id, winlog.event_data.TargetProcessGUID