endpoint(opens in a new tab or window)
windows(opens in a new tab or window)
process where
host.os.type == "windows" and event.type == "start" and
process.name : ("WINWORD.EXE", "EXCEL.EXE", "POWERPNT.EXE", "MSACCESS.EXE", "VSTOInstaller.exe") and
process.args regex~ """.+\.(wll|xll|ppa|ppam|xla|xlam|vsto)""" and
/* Office Add-In from suspicious paths */
(process.args :
("?:\\Users\\*\\Temp\\7z*",
"?:\\Users\\*\\Temp\\Rar$*",
"?:\\Users\\*\\Temp\\Temp?_*",
"?:\\Users\\*\\Temp\\BNZ.*",
"?:\\Users\\*\\Downloads\\*",
"?:\\Users\\*\\AppData\\Roaming\\*",
"?:\\Users\\Public\\*",
"?:\\ProgramData\\*",
"?:\\Windows\\Temp\\*",
"\\Device\\*",
"http*") or
process.parent.name : ("explorer.exe", "OpenWith.exe") or
/* Office Add-In from suspicious parent */
process.parent.name : ("cmd.exe", "powershell.exe")) and
/* False Positives */
not (process.args : "*.vsto" and
process.parent.executable :
("?:\\Program Files\\Logitech\\LogiOptions\\PlugInInstallerUtility*.exe",
"?:\\ProgramData\\Logishrd\\LogiOptions\\Plugins\\VSTO\\*\\VSTOInstaller.exe",
"?:\\Program Files\\Logitech\\LogiOptions\\PlugInInstallerUtility.exe",
"?:\\Program Files\\LogiOptionsPlus\\PlugInInstallerUtility*.exe",
"?:\\ProgramData\\Logishrd\\LogiOptionsPlus\\Plugins\\VSTO\\*\\VSTOInstaller.exe",
"?:\\Program Files\\Common Files\\microsoft shared\\VSTO\\*\\VSTOInstaller.exe")) and
not (process.args : "/Uninstall" and process.name : "VSTOInstaller.exe") and
not (process.parent.name : "rundll32.exe" and
process.parent.args : "?:\\WINDOWS\\Installer\\MSI*.tmp,zzzzInvokeManagedCustomActionOutOfProc") and
not (process.name : "VSTOInstaller.exe" and process.args : "https://dl.getsidekick.com/outlook/vsto/Sidekick.vsto")
Install detection rules in Elastic Security
Detect Suspicious Execution via Microsoft Office Add-Ins in the Elastic Security detection engine by installing this rule into your Elastic Stack.
To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).