rule WEBSHELL_JAVA_VersaMem_JAR_Aug24_1 {
   meta:
      description = "Detects VersaMem Java webshell samples (as used by Volt Typhoon)"
      author = "blacklotuslabs (modified by Florian Roth and X__Junior)"
      reference = "https://x.com/ryanaraine/status/1828440883315999117"
      date = "2024-08-27"
      modified = "2024-08-29"
      score = 75
      id = "9b666e61-cfa8-58b3-a362-772cd907c57c"
   strings:
      $sa1 = "com.versa.vnms.ui.TestMain"
      $sa2 = "captureLoginPasswordCode"
      $sa3 = "com/versa/vnms/ui/services/impl/VersaAuthenticationServiceImpl"
      $sa4 = "/tmp/.temp.data"
      $sa5 = "getInsertCode"
      $sa6 = "VersaMem"
      $sa7 = "Versa-Auth"

      $sb1 = "/tmp/.java_pid"
      $sb2 = {2f 75 73 72 2f 62 69 6e 2f 70 67 72 65 70 01 00 02 2d 66 01 00 25 6f 72 67 2e 61 70 61 63 68 65 2e 63 61 74 61 6c 69 6e 61 2e 73 74 61 72 74 75 70 2e 42 6f 6f 74 73 74 72 61 70 07}
   condition:
      filesize < 5MB and ( 3 of them or all of ($sb*) )
}

rule WEBSHELL_JAVA_VersaMem_JAR_Aug24_2 {
   meta:
      description = "Detects VersaMem Java webshell samples (as used by Volt Typhoon)"
      author = "Florian Roth"
      reference = "https://x.com/craiu/status/1828687700884336990"
      date = "2024-08-29"
      score = 75
      hash1 = "4bcedac20a75e8f8833f4725adfc87577c32990c3783bf6c743f14599a176c37"
      id = "5ca598ed-5d0a-563d-a5e8-f8229af2c949"
   strings:
      $x1 = "tomcat_memShell" ascii
      $x2 = "versa/vnms/ui/config/" ascii fullword
   condition:
      uint16(0) == 0x4b50
      and filesize < 3000KB
      and 1 of them
}