signature-base/yara/gen_susp_obfuscation.yar
2019-10-29 10:06:18 +01:00

44 lines
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rule SUSP_Base64_Encoded_Hex_Encoded_Code {
meta:
author = "Florian Roth"
description = "Detects hex encoded code that has been base64 encoded"
date = "2019-04-29"
score = 65
reference = "https://www.nextron-systems.com/2019/04/29/spotlight-threat-hunting-yara-rule-example/"
strings:
$x1 = { 78 34 4e ?? ?? 63 65 44 ?? ?? 58 48 67 }
$x2 = { 63 45 44 ?? ?? 58 48 67 ?? ?? ?? 78 34 4e }
$fp1 = "Microsoft Azure Code Signp$"
condition:
1 of ($x*) and not 1 of ($fp*)
}
rule SUSP_Double_Base64_Encoded_Executable {
meta:
description = "Detects an executable that has been encoded with base64 twice"
author = "Florian Roth"
reference = "https://twitter.com/TweeterCyber/status/1189073238803877889"
date = "2019-10-29"
hash1 = "1a172d92638e6fdb2858dcca7a78d4b03c424b7f14be75c2fd479f59049bc5f9"
strings:
$ = "VFZwVEFRR" ascii wide
$ = "RWcFRBUU" ascii wide
$ = "UVnBUQVFF" ascii wide
$ = "VFZvQUFBQ" ascii wide
$ = "RWb0FBQU" ascii wide
$ = "UVm9BQUFB" ascii wide
$ = "VFZxQUFBR" ascii wide
$ = "RWcUFBQU" ascii wide
$ = "UVnFBQUFF" ascii wide
$ = "VFZwUUFBS" ascii wide
$ = "RWcFFBQU" ascii wide
$ = "UVnBRQUFJ" ascii wide
$ = "VFZxUUFBT" ascii wide
$ = "RWcVFBQU" ascii wide
$ = "UVnFRQUFN" ascii wide
condition:
1 of them
}