SIGNATURE_BASE_WEBSHELL_ASPX_Compiled_Sharepoint_Drop_CVE_2025_53770_Jul25_2

rule SIGNATURE_BASE_WEBSHELL_ASPX_Compiled_Sharepoint_Drop_CVE_2025_53770_Jul25_2 : CVE_2025_53770 FILE
{
	meta:
		description = "Detects compiled ASPX web shell dropped during the exploitation of SharePoint RCE vulnerability CVE-2025-53770"
		author = "Florian Roth, Marius Benthin"
		id = "00a844ab-aede-53bf-820f-d43a5d96426d"
		date = "2025-07-20"
		modified = "2025-07-25"
		reference = "https://research.eye.security/sharepoint-under-siege/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/expl_sharepoint_jul25.yar#L23-L53"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "8d3d3f3a17d233bc8562765e61f7314ca7a08130ac0fb153ffd091612920b0f2"
		hash = "d8ca5e5d6400ac34ac4cc138efa89d2ec4d5c0e968a78fa3ba5dbc04c7550649"
		hash = "7e9b77da1f51d03ee2f96bc976f6aeb781f801cf633862a4b8c356cbb555927d"
		logic_hash = "df11e5bd293cf094f3a147b54ecaafbe0804d7d575fcc22f38e77ab155c7ebdc"
		score = 75
		quality = 83
		tags = "CVE-2025-53770, FILE"

	strings:
		$x1 = /App_Web_spinstall\d{0,1}.aspx/ wide
		$x2 = /spinstall[\w]?[\._]aspx/ ascii
		$x3 = /\/_layouts\/1[0-9]\/spinstall/ wide
		$x4 = /\/_layouts\/1[0-9]\/ghostfile/ wide
		$s1 = "System.Web.Configuration.MachineKeySection" wide
		$s2 = "Page_load" ascii fullword
		$s3 = "GetApplicationConfig" wide fullword

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 20KB and ( 1 of ( $x* ) or all of ( $s* ) ) or 2 of ( $x* ) or 4 of them
}