ESET_IIS_Group05_Iistealer

import "pe"

private rule ESET_IIS_Native_Module_PRIVATE : FILE
{
	meta:
		description = "Signature to match an IIS native module (clean or malicious)"
		author = "ESET Research"
		id = "e3bacdc8-fde1-5e83-ac94-79fc345e888d"
		date = "2021-08-04"
		modified = "2021-08-04"
		reference = "https://github.com/eset/malware-ioc/"
		source_url = "https://github.com/eset/malware-ioc/blob/17baf44964a77368e9149f4f593eb098beddf1c5/badiis/badiis.yar#L34-L92"
		license_url = "https://github.com/eset/malware-ioc/blob/17baf44964a77368e9149f4f593eb098beddf1c5/LICENSE"
		logic_hash = "5a388dc3253df606e2648d1f9c018e6dde373bbddce66dba69b7aecdd95bac18"
		score = 75
		quality = 55
		tags = "FILE"
		license = "BSD 2-Clause"
		version = "1"

	strings:
		$e1 = "This module subscribed to event"
		$e2 = "CHttpModule::OnBeginRequest"
		$e3 = "CHttpModule::OnPostBeginRequest"
		$e4 = "CHttpModule::OnAuthenticateRequest"
		$e5 = "CHttpModule::OnPostAuthenticateRequest"
		$e6 = "CHttpModule::OnAuthorizeRequest"
		$e7 = "CHttpModule::OnPostAuthorizeRequest"
		$e8 = "CHttpModule::OnResolveRequestCache"
		$e9 = "CHttpModule::OnPostResolveRequestCache"
		$e10 = "CHttpModule::OnMapRequestHandler"
		$e11 = "CHttpModule::OnPostMapRequestHandler"
		$e12 = "CHttpModule::OnAcquireRequestState"
		$e13 = "CHttpModule::OnPostAcquireRequestState"
		$e14 = "CHttpModule::OnPreExecuteRequestHandler"
		$e15 = "CHttpModule::OnPostPreExecuteRequestHandler"
		$e16 = "CHttpModule::OnExecuteRequestHandler"
		$e17 = "CHttpModule::OnPostExecuteRequestHandler"
		$e18 = "CHttpModule::OnReleaseRequestState"
		$e19 = "CHttpModule::OnPostReleaseRequestState"
		$e20 = "CHttpModule::OnUpdateRequestCache"
		$e21 = "CHttpModule::OnPostUpdateRequestCache"
		$e22 = "CHttpModule::OnLogRequest"
		$e23 = "CHttpModule::OnPostLogRequest"
		$e24 = "CHttpModule::OnEndRequest"
		$e25 = "CHttpModule::OnPostEndRequest"
		$e26 = "CHttpModule::OnSendResponse"
		$e27 = "CHttpModule::OnMapPath"
		$e28 = "CHttpModule::OnReadEntity"
		$e29 = "CHttpModule::OnCustomRequestNotification"
		$e30 = "CHttpModule::OnAsyncCompletion"
		$e31 = "CGlobalModule::OnGlobalStopListening"
		$e32 = "CGlobalModule::OnGlobalCacheCleanup"
		$e33 = "CGlobalModule::OnGlobalCacheOperation"
		$e34 = "CGlobalModule::OnGlobalHealthCheck"
		$e35 = "CGlobalModule::OnGlobalConfigurationChange"
		$e36 = "CGlobalModule::OnGlobalFileChange"
		$e37 = "CGlobalModule::OnGlobalApplicationStart"
		$e38 = "CGlobalModule::OnGlobalApplicationResolveModules"
		$e39 = "CGlobalModule::OnGlobalApplicationStop"
		$e40 = "CGlobalModule::OnGlobalRSCAQuery"
		$e41 = "CGlobalModule::OnGlobalTraceEvent"
		$e42 = "CGlobalModule::OnGlobalCustomNotification"
		$e43 = "CGlobalModule::OnGlobalThreadCleanup"
		$e44 = "CGlobalModule::OnGlobalApplicationPreload"

	condition:
		uint16( 0 ) == 0x5A4D and pe.exports ( "RegisterModule" ) and any of ( $e* )
}

rule ESET_IIS_Group05_Iistealer
{
	meta:
		description = "Detects Group 5 native IIS malware family (IIStealer)"
		author = "ESET Research"
		id = "598ec6b2-0349-5da7-acad-72ef2468b927"
		date = "2021-08-04"
		modified = "2021-08-04"
		reference = "https://github.com/eset/malware-ioc/"
		source_url = "https://github.com/eset/malware-ioc/blob/17baf44964a77368e9149f4f593eb098beddf1c5/badiis/badiis.yar#L201-L232"
		license_url = "https://github.com/eset/malware-ioc/blob/17baf44964a77368e9149f4f593eb098beddf1c5/LICENSE"
		logic_hash = "5dff445121fda59df805d6fcb5db3f8f8e52a6e63e2da2a6875f8c9ad9cafc72"
		score = 75
		quality = 80
		tags = ""
		license = "BSD 2-Clause"
		version = "1"

	strings:
		$s1 = "tojLrGzFMbcDTKcH" ascii wide
		$s2 = "4vUOj3IutgtrpVwh" ascii wide
		$s3 = "SoUnRCxgREXMu9bM" ascii wide
		$s4 = "9Zr1Z78OkgaXj1Xr" ascii wide
		$s5 = "cache.txt" ascii wide
		$s6 = "/checkout/checkout.aspx" ascii wide
		$s7 = "/checkout/Payment.aspx" ascii wide
		$s8 = "/privacy.aspx"
		$s9 = "X-IIS-Data"
		$s10 = "POST"
		$s11 = {C7 ?? CF 2F 00 63 00 C7 ?? D3 68 00 65 00 C7 ?? D7 63 00 6B 00 C7 ?? DB 6F 00 75 00 C7 ?? DF 74 00 2F 00 C7 ?? E3 63 00 68 00 C7 ?? E7 65 00 63 00 C7 ?? EB 6B 00 6F 00 C7 ?? EF 75 00 74 00 C7 ?? F3 2E 00 61 00 C7 ?? F7 73 00 70 00 C7 ?? FB 78 00 00 00}
		$s12 = {C7 ?? AF 2F 00 70 00 C7 ?? B3 72 00 69 00 C7 ?? B7 76 00 61 00 C7 ?? BB 63 00 79 00 C7 ?? BF 2E 00 61 00 C7 ?? C3 73 00 70 00 C7 ?? C7 78 00 00 00}

	condition:
		ESET_IIS_Native_Module_PRIVATE and 3 of ( $s* )
}