Create apt_volttyphoon_versamem.yar

Author: Neo23x0

yara/apt_volttyphoon_versamem.yar

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+
+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)"
+      reference = "https://x.com/ryanaraine/status/1828440883315999117"
+      date = "2024-08-27"
+      modified = "2024-08-29"
+      score = 75
+   strings:
+      $s1 = "com.versa.vnms.ui.TestMain"
+      $s2 = "/tmp/.java_pid"
+      $s3 = "captureLoginPasswordCode"
+      $s4 = "com/versa/vnms/ui/services/impl/VersaAuthenticationServiceImpl"
+      $s5 = "/tmp/.temp.data"
+      $s6 = "getInsertCode"
+      $s7 = "VersaMem"
+      $s8 = "Versa-Auth"
+   condition:
+      filesize < 5MB and 3 of them
+}
+
+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"
+   strings:
+      $x1 = "tomcat_memShell" ascii fullword
+      $x2 = "versa/vnms/ui/config/" ascii fullword
+   condition:
+      uint16(0) == 0x4b50
+      and filesize < 3000KB
+      and 6 of ($s*)
+}