persistence_of_ryuk_ransomware

rule persistence_of_ryuk_ransomware {
 meta:
    author = "Emir Erdogan"
    description = "Ryuk has been know to be a part of a bigger \"Triple Threat\" attack that involves Emotet and TrickBot.  License: https://github.com/Neo23x0/sigma/blob/master/LICENSE.Detection.Rules.md."
    reference = "https://tdm.socprime.com/tdm/info/eWyQLgWZwv3v"
    version = "0.01"
    created = "2021-03-09"
    product = "windows"
    service = "sysmon"
    mitre = "T1055, T1060, T1112, T1012, T1486"

  events:
(re.regex($selection1.target.process.file.full_path, `.*\\reg\.exe`) and re.regex($selection1.principal.process.file.full_path, `.*\\cmd\.exe`) and (re.regex($selection1.target.process.command_line, `REG ADD \"HKEY_CURRENT_USER\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run\" /v \"svchos\" /t REG_SZ /d \".*\\BPWPc\.exe\" /f`) or re.regex($selection1.target.process.command_line, `REG  ADD \"HKEY_CURRENT_USER\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run\" /v \"svchos\" /t REG_SZ /d \".*\\YLZHK\.exe\" /f`) or re.regex($selection1.target.process.command_line, `REG  ADD \"HKEY_CURRENT_USER\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run\" /v \"svchos\" /t REG_SZ /d \".*\\rojwa\.exe\" /f`)) and ($selection1.target.process.command_line = "vssadmin Delete Shadows /all /quiet" or re.regex($selection1.target.process.command_line, `vssadmin resize shadowstorage.*.*`)))

  condition:
    $selection1
}