signature-base/yara/apt_ta17_318A.yar

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/*
Yara Rule Set
Author: US CERT
Date: 2017-11-15
Identifier: Hidden Cobra Fall Chill
Reference: https://www.us-cert.gov/ncas/alerts/TA17-318A
*/
rule TA17_318A_rc4_stack_key_fallchill {
meta:
description = "HiddenCobra FallChill - rc4_stack_key"
author = "US CERT"
reference = "https://www.us-cert.gov/ncas/alerts/TA17-318B"
date = "2017-11-15"
strings:
$stack_key = { 0d 06 09 2a ?? ?? ?? ?? 86 48 86 f7 ?? ?? ?? ?? 0d 01 01 01 ?? ?? ?? ?? 05 00 03 82 41 8b c9 41 8b d1 49 8b 40 08 48 ff c2 88 4c 02 ff ff c1 81 f9 00 01 00 00 7c eb }
condition:
(uint16(0) == 0x5A4D and uint16(uint32(0x3c)) == 0x4550) and $stack_key
}
rule TA17_318A_success_fail_codes_fallchill {
meta:
description = "HiddenCobra FallChill - success_fail_codes"
author = "US CERT"
reference = "https://www.us-cert.gov/ncas/alerts/TA17-318B"
date = "2017-11-15"
strings:
$s0 = { 68 7a 34 12 00 }
$s1 = { ba 7a 34 12 00 }
$f0 = { 68 5c 34 12 00 }
$f1 = { ba 5c 34 12 00 }
condition:
(uint16(0) == 0x5A4D and uint16(uint32(0x3c)) == 0x4550) and (($s0 and $f0) or ($s1 and $f1))
}
/*
Yara Rule Set
Author: Florian Roth
Date: 2017-11-15
Identifier: Hidden Cobra Fall Chill
Reference: https://www.us-cert.gov/ncas/alerts/TA17-318A
*/
import "pe"
/* Rule Set ----------------------------------------------------------------- */
rule HiddenCobra_FallChill_1 {
meta:
description = "Auto-generated rule"
license = "https://creativecommons.org/licenses/by-nc/4.0/"
author = "Florian Roth"
reference = "https://www.us-cert.gov/ncas/alerts/TA17-318A"
date = "2017-11-15"
hash1 = "a606716355035d4a1ea0b15f3bee30aad41a2c32df28c2d468eafd18361d60d6"
strings:
$s1 = "REGSVR32.EXE.MUI" fullword wide
$s2 = "Microsoft Corporation. All rights reserved." fullword wide
$s3 = "c%sd.e%sc %s > \"%s\" 2>&1" fullword wide
$s4 = "\" goto Loop" fullword ascii
$e1 = "xolhvhlxpvg" fullword ascii
$e2 = "tvgslhgybmanv" fullword ascii
$e3 = "CivagvTllosvok32Smakhslg" fullword ascii
$e4 = "GvgCfiivmgDrivxglibW" fullword ascii
$e5 = "OkvmPilxvhhTlpvm" fullword ascii
condition:
uint16(0) == 0x5a4d and filesize < 300KB and (
pe.imphash() == "6135d9bc3591ae7bc72d070eadd31755" or
3 of ($s*) or
4 of them
)
}
rule HiddenCobra_FallChill_2 {
meta:
description = "Auto-generated rule"
license = "https://creativecommons.org/licenses/by-nc/4.0/"
author = "Florian Roth"
reference = "https://www.us-cert.gov/ncas/alerts/TA17-318A"
date = "2017-11-15"
hash1 = "0a118eb23399000d148186b9079fa59caf4c3faa7e7a8f91533e467ac9b6ff41"
strings:
$s1 = "%s\\%s.dll" fullword wide
$s2 = "yurdkr.dll" fullword ascii
$s3 = "c%sd.e%sc %s > \"%s\" 2>&1" fullword wide
condition:
uint16(0) == 0x5a4d and filesize < 500KB and (
pe.imphash() == "cb36dcb9909e29a38c387b8a87e7e4ed" or
( 2 of them )
)
}