75 lines
2.4 KiB
Text
75 lines
2.4 KiB
Text
/*
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Yara Rule Set
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Author: Florian Roth
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Date: 2017-06-22
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Identifier: ISESteroids
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Reference: https://twitter.com/danielhbohannon/status/877953970437844993
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*/
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/* Rule Set ----------------------------------------------------------------- */
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rule PowerShell_ISESteroids_Obfuscation {
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meta:
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description = "Detects PowerShell ISESteroids obfuscation"
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license = "Detection Rule License 1.1 https://github.com/Neo23x0/signature-base/blob/master/LICENSE"
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author = "Florian Roth (Nextron Systems)"
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reference = "https://twitter.com/danielhbohannon/status/877953970437844993"
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date = "2017-06-23"
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id = "d686c4de-28fd-5d77-91d4-dde5661b75cd"
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strings:
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$x1 = "/\\/===\\__" ascii
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$x2 = "${__/\\/==" ascii
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$x3 = "Catch { }" fullword ascii
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$x4 = "\\_/=} ${_" ascii
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condition:
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2 of them
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}
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rule SUSP_Obfuscted_PowerShell_Code {
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meta:
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description = "Detects obfuscated PowerShell Code"
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date = "2018-12-13"
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author = "Florian Roth (Nextron Systems)"
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reference = "https://twitter.com/silv0123/status/1073072691584880640"
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id = "e2d8fc9e-ce2b-5118-8305-0d5839561d4f"
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strings:
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$s1 = "').Invoke(" ascii
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$s2 = "(\"{1}{0}\"" ascii
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$s3 = "{0}\" -f" ascii
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condition:
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#s1 > 11 and #s2 > 10 and #s3 > 10
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}
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rule SUSP_PowerShell_Caret_Obfuscation_2 {
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meta:
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description = "Detects powershell keyword obfuscated with carets"
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author = "Florian Roth (Nextron Systems)"
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reference = "Internal Research"
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date = "2019-07-20"
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id = "976e261a-029c-5703-835f-a235c5657471"
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strings:
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$r1 = /p[\^]?o[\^]?w[\^]?e[\^]?r[\^]?s[\^]?h[\^]?e[\^]?l\^l/ ascii wide nocase fullword
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$r2 = /p\^o[\^]?w[\^]?e[\^]?r[\^]?s[\^]?h[\^]?e[\^]?l[\^]?l/ ascii wide nocase fullword
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condition:
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1 of them
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}
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rule SUSP_OBFUSC_PowerShell_True_Jun20_1 {
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meta:
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description = "Detects indicators often found in obfuscated PowerShell scripts"
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author = "Florian Roth (Nextron Systems)"
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reference = "https://github.com/corneacristian/mimikatz-bypass/"
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date = "2020-06-27"
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score = 75
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id = "e9bb870b-ad72-57d3-beff-2f84a81490eb"
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strings:
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$ = "${t`rue}" ascii nocase
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$ = "${tr`ue}" ascii nocase
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$ = "${tru`e}" ascii nocase
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$ = "${t`ru`e}" ascii nocase
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$ = "${tr`u`e}" ascii nocase
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$ = "${t`r`ue}" ascii nocase
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$ = "${t`r`u`e}" ascii nocase
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condition:
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filesize < 6000KB and 1 of them
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}
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