SIGNATURE_BASE_SUSP_Base64_Encoded_Exploit_Indicators_Dec21

rule SIGNATURE_BASE_SUSP_Base64_Encoded_Exploit_Indicators_Dec21 : CVE_2021_44228
{
	meta:
		description = "Detects base64 encoded strings found in payloads of exploits against log4j CVE-2021-44228"
		author = "Florian Roth (Nextron Systems)"
		id = "09abc4f0-ace7-5f53-b1d3-5f5c6bf3bdba"
		date = "2021-12-10"
		modified = "2021-12-13"
		reference = "https://twitter.com/Reelix/status/1469327487243071493"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/expl_log4j_cve_2021_44228.yar#L142-L165"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "703a83916c7279bcdc3cd61602472c2a3815140235be169f5b2063a547438c61"
		score = 70
		quality = 85
		tags = "CVE-2021-44228"

	strings:
		$sa1 = "Y3VybCAtcy"
		$sa2 = "N1cmwgLXMg"
		$sa3 = "jdXJsIC1zI"
		$sb1 = "fHdnZXQgLXEgLU8tI"
		$sb2 = "x3Z2V0IC1xIC1PLS"
		$sb3 = "8d2dldCAtcSAtTy0g"
		$fp1 = "<html"

	condition:
		1 of ( $sa* ) and 1 of ( $sb* ) and not 1 of ( $fp* )
}