signature-base/yara/gen_cert_payloads.yar
2018-08-21 10:58:45 +02:00

22 lines
698 B
Plaintext

rule SUSP_certificate_payload {
meta:
description = "Detects payloads that pretend to be certificates"
date = "2018/08/02"
author = "Didier Stevens, Florian Roth"
reference = "https://blog.nviso.be/2018/08/02/powershell-inside-a-certificate-part-3/"
score = 50
strings:
$re1 = "-----BEGIN CERTIFICATE-----"
$fp1 = "replace it with the PEM-encoded root certificate"
condition:
uint32(0) == 0x2D2D2D2D
and $re1 at 0
/* not 'M' at position 29, which is after the BEGIN CERTIFICATE header plus line break */
/* \r\n */
and not uint8(29) == 0x4D
/* \n */
and not uint8(28) == 0x4D
and not 1 of ($fp*)
}