/* State-sponsored Casper Malware Rules by @4nc4p - attribution and analysis by @pinkflawd @r00tbsd @circl_lu */

rule Casper_Backdoor_x86 {
   meta:
      description = "Casper French Espionage Malware - Win32/ProxyBot.B - x86 Payload http://goo.gl/VRJNLo"
      author = "Florian Roth (Nextron Systems)"
      reference = "http://goo.gl/VRJNLo"
      date = "2015-03-05"
      modified = "2023-01-27"
      hash = "f4c39eddef1c7d99283c7303c1835e99d8e498b0"
      score = 80
      id = "9e54f00c-74a7-56cc-87e5-8dec1233cbb5"
   strings:
      $s1 = "\"svchost.exe\"" fullword wide
      $s2 = "firefox.exe" fullword ascii
      $s3 = "\"Host Process for Windows Services\"" fullword wide

      $x1 = "\\Users\\*" ascii
      $x2 = "\\Roaming\\Mozilla\\Firefox\\Profiles\\*" ascii
      $x3 = "\\Mozilla\\Firefox\\Profiles\\*" ascii
      $x4 = "\\Documents and Settings\\*" ascii

      $y1 = "%s; %S=%S" fullword wide
      $y2 = "%s; %s=%s" fullword ascii
      $y3 = "Cookie: %s=%s" fullword ascii
      $y4 = "http://%S:%d" fullword wide

      $z1 = "http://google.com/" ascii
      $z2 = "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; MALC)" fullword ascii
      $z3 = "Operating System\"" fullword wide
   condition:
      ( filesize < 250KB and all of ($s*) ) or
      ( 3 of ($x*) and 2 of ($y*) and 2 of ($z*) )
}

rule Casper_EXE_Dropper {
	meta:
		description = "Casper French Espionage Malware - Win32/ProxyBot.B - Dropper http://goo.gl/VRJNLo"
		license = "Detection Rule License 1.1 https://github.com/Neo23x0/signature-base/blob/master/LICENSE"
		author = "Florian Roth (Nextron Systems)"
		reference = "http://goo.gl/VRJNLo"
		date = "2015/03/05"
		hash = "e4cc35792a48123e71a2c7b6aa904006343a157a"
		score = 80
		id = "a901d045-6f9b-57e8-8347-6f78178b7231"
	strings:
		$s0 = "<Command>" fullword ascii
		$s1 = "</Command>" fullword ascii
		$s2 = "\" /d \"" fullword ascii
		$s4 = "'%s' %s" fullword ascii
		$s5 = "nKERNEL32.DLL" fullword wide
		$s6 = "@ReturnValue" fullword wide
		$s7 = "ID: 0x%x" fullword ascii
		$s8 = "Name: %S" fullword ascii
	condition:
		7 of them
}

rule Casper_Included_Strings {
	meta:
		description = "Casper French Espionage Malware - String Match in File - http://goo.gl/VRJNLo"
		license = "Detection Rule License 1.1 https://github.com/Neo23x0/signature-base/blob/master/LICENSE"
		author = "Florian Roth (Nextron Systems)"
		reference = "http://goo.gl/VRJNLo"
		date = "2015/03/06"
		score = 50
		id = "34ba474d-0858-534a-8f32-db5a709e8814"
	strings:
		$a0 = "cmd.exe /C FOR /L %%i IN (1,1,%d) DO IF EXIST"
		$a1 = "& SYSTEMINFO) ELSE EXIT"

		$c1 = "domcommon.exe" wide fullword							// File Name
		$c2 = "jpic.gov.sy" fullword 								// C2 Server
		$c3 = "aiomgr.exe" wide fullword							// File Name
		$c4 = "perfaudio.dat" fullword								// Temp File Name
		$c5 = "Casper_DLL.dll" fullword								// Name
		$c6 = { 7B 4B 59 DE 37 4A 42 26 59 98 63 C6 2D 0F 57 40 } 	// Decryption Key
		$c7 = "{4216567A-4512-9825-7745F856}" fullword 				// Mutex
	condition:
		all of ($a*) or
		uint16(0) == 0x5a4d and ( 1 of ($c*) )
}

rule Casper_SystemInformation_Output {
	meta:
		description = "Casper French Espionage Malware - System Info Output - http://goo.gl/VRJNLo"
		license = "Detection Rule License 1.1 https://github.com/Neo23x0/signature-base/blob/master/LICENSE"
		author = "Florian Roth (Nextron Systems)"
		reference = "http://goo.gl/VRJNLo"
		date = "2015/03/06"
		score = 70
		id = "aaae200c-7ef1-52eb-be5b-36e0ad29ecef"
	strings:
		$a0 = "***** SYSTEM INFORMATION ******"
		$a1 = "***** SECURITY INFORMATION ******"
		$a2 = "Antivirus: "
		$a3 = "Firewall: "
		$a4 = "***** EXECUTION CONTEXT ******"
		$a5 = "Identity: "
		$a6 = "<CONFIG TIMESTAMP="
	condition:
		all of them
}