Create a file on vulnerable Server

count sequences of printable characters with the minimum length of 7

strings --bytes=7 sample.exe | wc -l

Rule to detect cmd.exe

offset.yar

rule cmd_rule
{
    strings:
       $s = "cmd.exe /c \"%s\""

    condition:
       $s
}

sudo yara /home/student/Desktop/rules/offset.yar . -s

Rule to identify PE file type

pe.yar

rule IsPeFile {
	strings:
		$mz = "MZ"

	condition:
		$mz at 0 and uint32(uint32(0x3C)) == 0x4550
}

Rule to detect maleware in PE Files

malware.yar

rule str_rule
{
    meta:
        description = "intel - file strings.txt"
        author = "rsi"
        date = "2021-06-19"
    strings:
        $s1 = "WWWWWPj" fullword ascii
        $s2 = "OpenSCManagerA" fullword ascii
        $s3 = ";22dV::tN" fullword ascii
        $s4 = "_local_unwind2" fullword ascii
        $s5 = "2+( VPOL" fullword ascii
        $s6 = "GlobalAlloc" fullword ascii
        $s7 = "VirtualProtect" fullword ascii
        $s8 = "@Pbmx~P" fullword ascii
        $s9 = "FreeLibrary" fullword ascii
        $s10 = "^Fr`+:&" fullword ascii
        $s11 = "VirtualAlloc" fullword ascii
        $s12 = "CreateDirectoryW" fullword ascii
        $s13 = ">k_I[$" fullword ascii
        $s14 = "msg/m_english.wnryF" fullword ascii
        $s15 = "StartServiceA" fullword ascii
        $s16 = ":*>B=Ox" fullword ascii
        $s17 = "OpenMutexA" fullword ascii
        $s18 = "GetFullPathNameA" fullword ascii
        $s19 = "RegSetValueExA" fullword ascii
        $s20 = "msg/m_french.wnry" fullword ascii
        $s21 = "DeleteFileW" fullword ascii
        $s22 = "QeTbF~ZiKw" fullword ascii
        $s23 = "SbElHtQeF" fullword ascii
        $s24 = "Q~TbFwZiK" fullword ascii
        $s25 = "CreateFileW" fullword ascii
        $s26 = ".?AVtype_info@@" fullword ascii
        $s27 = "CryptDecrypt" fullword ascii
        $s28 = "=j&&LZ66lA??~" fullword ascii
        $s29 = "F~TbKwZi" fullword ascii
        $s30 = "incorrect data check" fullword ascii
        $s31 = "tasksche.exe" fullword ascii
        $s32 = "MoveFileW" fullword ascii
        $s33 = "unknown compression method" fullword ascii
        $s34 = "??1exception@@UAE@XZ" fullword ascii
        $s35 = "realloc" fullword ascii
        $s36 = "SetCurrentDirectoryA" fullword ascii
        $s37 = "WriteFile" fullword ascii
        $s38 = "b4(X2;ey" fullword ascii
        $s39 = "__p__commode" fullword ascii
        $s40 = "MultiByteToWideChar" fullword ascii
        $s41 = "LoadLibraryA" fullword ascii
        $s42 = "6tGuzF" fullword ascii
        $s43 = "%%Jo..r" fullword ascii
        $s44 = "4$8,9-6'.6$:#?*1hHpXeA~SrZlN" fullword ascii
        $s45 = "PPxD<<%" fullword ascii
        $s46 = "kernel32.dll" fullword ascii
        $s47 = "&%^W6)." fullword ascii
        $s48 = "CryptImportKey" fullword ascii
        $s49 = "HeapFree" fullword ascii
        $s50 = "_except_handler3" fullword ascii
        $s51 = "WaitForSingleObject" fullword ascii
        $s52 = "V,YYG;~" fullword ascii
        $s53 = "Ud|JZ|BE" fullword ascii
        $s54 = "_CxxThrowException" fullword ascii
        $s55 = "data error" fullword ascii
        $s56 = "??0exception@@QAE@ABQBD@Z" fullword ascii
        $s57 = "_acmdln" fullword ascii
        $s58 = "OLEAUT32.dll" fullword ascii
        $s59 = ";u>H4q7.c" fullword ascii
        $s60 = "GetModuleHandleA" fullword ascii
        $s61 = "incomplete literal/length tree" fullword ascii
        $s62 = "OpenServiceA" fullword ascii
        $s63 = "CryptReleaseContext" fullword ascii
        $s64 = "attrib +h ." fullword ascii
        $s65 = "inflate 1.1.3 Copyright 1995-1998 Mark Adler" fullword ascii
        $s66 = "12t9YDPgwueZ9NyMgw519p7AA8isjr6SMw" fullword ascii
        $s67 = "insufficient memory" fullword ascii
        $s68 = "$`GnP+%<g" fullword ascii
        $s69 = "TaskStart" fullword ascii
        $s70 = "msg/m_chinese (traditional).wnry" fullword ascii
        $s71 = "[_:L	x86" fullword ascii
        $s72 = "ReadFile" fullword ascii
        $s73 = "Bb..fO3" fullword ascii
        $s74 = "qDj$bIU" fullword ascii
        $s75 = "k|_^][Y" fullword ascii
        $s76 = "invalid distance code" fullword ascii
        $s77 = "wcsrchr" fullword ascii
        $s78 = "GetFileSizeEx" fullword ascii
        $s79 = "L)b7=a`" fullword ascii
        $s80 = "__CxxFrameHandler" fullword ascii
        $s81 = "_stricmp" fullword ascii
        $s82 = "[4+G[Tnr" fullword ascii
        $s83 = "13AM4VW2dhxYgXeQepoHkHSQuy6NgaEb94" fullword ascii
        $s84 = "msg/m_croatian.wnry" fullword ascii
        $s85 = "CMnQ,OOr" fullword ascii
        $s86 = "swprintf" fullword ascii
        $s87 = "SetFileAttributesW" fullword ascii
        $s88 = "msg/m_czech.wnryn" fullword ascii
        $s89 = "O|x8+^_" fullword ascii
        $s90 = "HeapAlloc" fullword ascii
        $s91 = "__setusermatherr" fullword ascii
        $s92 = "GetWindowsDirectoryW" fullword ascii
        $s93 = "115p7UMMngoj1pMvkpHijcRdfJNXj6LrLn" fullword ascii
        $s94 = "LocalFileTimeToFileTime" fullword ascii
        $s95 = "3/Vq9	=" fullword ascii
        $s96 = "CryptAcquireContextA" fullword ascii
        $s97 = "Jo7eQX%" fullword ascii
        $s98 = "FindResourceA" fullword ascii
        $s99 = "'B;1?5s" fullword ascii
        $s100 = "IsBadReadPtr" fullword ascii
        $s101 = "GetExitCodeProcess" fullword ascii
        $s102 = "`.rdata" fullword ascii
        $s103 = "#`?@/9P" fullword ascii
        $s104 = "GetTempPathW" fullword ascii
        $s105 = "invalid bit length repeat" fullword ascii
        $s106 = "MSVCRT.dll" fullword ascii
        $s107 = "o%%Jr..$" fullword ascii
        $s108 = "GlobalMsWinZonesCacheCounterMutexA" fullword ascii
        $s109 = "!`7RNkv" fullword ascii
        $s110 = "__p___argc" fullword ascii
        $s111 = "SetCurrentDirectoryW" fullword ascii
        $s112 = "oversubscribed literal/length tree" fullword ascii
        $s113 = "[l~y2U=" fullword ascii
        $s114 = "msg/m_greek.wnry4n" fullword ascii
        $s115 = "invalid block type" fullword ascii
        $s116 = "<` Xu9g" fullword ascii
        $s117 = "GetNativeSystemInfo" fullword ascii
        $s118 = "CloseServiceHandle" fullword ascii
        $s119 = "incomplete distance tree" fullword ascii
        $s120 = "S	Q+c@x" fullword ascii
        $s121 = "8d62ro/" fullword ascii
        $s122 = "e	];F[p" fullword ascii
        $s123 = "$@^ Y+kCM3" fullword ascii
        $s124 = "X(N.K&9" fullword ascii
        $s125 = "LeaveCriticalSection" fullword ascii
        $s126 = "msg/m_bulgarian.wnry" fullword ascii
        $s127 = "B~WJLuC" fullword ascii
        $s128 = "invalid window size" fullword ascii
        $s129 = "msg/m_dutch.wnry9" fullword ascii
        $s130 = "GetCurrentDirectoryA" fullword ascii
        $s131 = "Hy}V2l0e" fullword ascii
        $s132 = "xxJo%%r..8$" fullword ascii
        $s133 = "NLc>zQy" fullword ascii
        $s134 = "=iF-s4\"t" fullword ascii
        $s135 = "GetFileAttributesA" fullword ascii
        $s136 = "_initterm" fullword ascii
        $s137 = "2{0ONU	T8" fullword ascii
        $s138 = "M{_rKG	C" fullword ascii
        $s139 = "4XI\"whG" fullword ascii
        $s140 = "DeleteCriticalSection" fullword ascii
        $s141 = "b.wnryP8" fullword ascii
        $s142 = "GetFileSize" fullword ascii
        $s143 = "GetFileAttributesW" fullword ascii
        $s144 = "md)(:--" fullword ascii
        $s145 = "WNcry@2ol7" fullword ascii
        $s146 = "empty distance tree with lengths" fullword ascii
        $s147 = "SizeofResource" fullword ascii
        $s148 = "CopyFileA" fullword ascii
        $s149 = "uo\"usd/" fullword ascii
        $s150 = "ciC [/K" fullword ascii
        $s151 = "$0vJ<T9" fullword ascii
        $s152 = "icacls . /grant Everyone:F /T /C /Q" fullword ascii
        $s153 = "CryptDestroyKey" fullword ascii
        $s154 = "oversubscribed distance tree" fullword ascii
        $s155 = "MoveFileExW" fullword ascii
        $s156 = "KfmZ@9q" fullword ascii
        $s157 = "TerminateProcess" fullword ascii
        $s158 = "stream end" fullword ascii
        $s159 = "c.wnry%" fullword ascii
        $s160 = "vi#<!d*S" fullword ascii
        $s161 = "pfgGL`R" fullword ascii
        $s162 = "_XcptFilter" fullword ascii
        $s163 = "RegCreateKeyW" fullword ascii
        $s164 = "[wS#C^6" fullword ascii
        $s165 = "file error" fullword ascii
        $s166 = ">nuGl=Cme4" fullword ascii
        $s167 = "Microsoft Enhanced RSA and AES Cryptographic Provider" fullword ascii
        $s168 = "msg/m_filipino.wnry" fullword ascii
        $s169 = "incomplete dynamic bit lengths tree" fullword ascii
        $s170 = ".?AVexception@@" fullword ascii
        $s171 = "b=htZo&f" fullword ascii
        $s172 = "KERNEL32.dll" fullword ascii
        $s173 = "msg/m_chinese (simplified).wnryR9" fullword ascii
        $s174 = "&&Lj66lZ??~A" fullword ascii
        $s175 = "#E.(`MW" fullword ascii
        $s176 = "cmd.exe /c \"%s\"" fullword ascii
        $s177 = "j_1lTo`" fullword ascii
        $s178 = "stream error" fullword ascii
        $s179 = "&Lj&6lZ6?~A?" fullword ascii
        $s180 = "WS2_32.dll" fullword ascii
        $s181 = "SystemTimeToFileTime" fullword ascii
        $s182 = "- unzip 0.15 Copyright 1998 Gilles Vollant" fullword ascii
        $s183 = "??0exception@@QAE@ABV0@@Z" fullword ascii
        $s184 = ",4$8'9-6:.6$1#?*XhHpSeA~NrZlE" fullword ascii
        $s185 = "CloseHandle" fullword ascii
        $s186 = "??2@YAPAXI@Z" fullword ascii
        $s187 = "SetFileTime" fullword ascii
        $s188 = "|~}%.15" fullword ascii
        $s189 = "GetProcessHeap" fullword ascii
        $s190 = "SE{^QC4" fullword ascii
        $s191 = "Df\"\"T~**;" fullword ascii
        $s192 = "wsprintfA" fullword ascii
        $s193 = "GetModuleFileNameA" fullword ascii
        $s194 = "RegQueryValueExA" fullword ascii
        $s195 = "2/O-_.X8w.+" fullword ascii
        $s196 = "s<,kX5k" fullword ascii
        $s197 = "4I_,eJi" fullword ascii
        $s198 = "CreateServiceA" fullword ascii
        $s199 = "f\"\"D~**T" fullword ascii
        $s200 = "_controlfp" fullword ascii
        $s201 = "incompatible version" fullword ascii
        $s202 = "dV22tN::" fullword ascii
        $s203 = "_-TPsPUv: V" fullword ascii
        $s204 = "IyEf [%" fullword ascii
        $s205 = "__set_app_type" fullword ascii
        $s206 = "InitializeCriticalSection" fullword ascii
        $s207 = "Hjz%3(0" fullword ascii
        $s208 = ".Vy_Fdk" fullword ascii
        $s209 = "'Oh'-o]" fullword ascii
        $s210 = "qr=_os*" fullword ascii
        $s211 = ",MF3j;2@" fullword ascii
        $s212 = "need dictionary" fullword ascii
        $s213 = "CreateDirectoryA" fullword ascii
        $s214 = "pq\"b\"V1" fullword ascii
        $s215 = "=XnFQ-Il" fullword ascii
        $s216 = "x%Jo%.r." fullword ascii
        $s217 = "GetProcAddress" fullword ascii
        $s218 = "CryptEncrypt" fullword ascii
        $s219 = "MSVCP60.dll" fullword ascii
        $s220 = "6P>YK^$r" fullword ascii
        $s221 = "__p___argv" fullword ascii
        $s222 = "sprintf" fullword ascii
        $s223 = "MF2E0UG" fullword ascii
        $s224 = "KPeJr}F" fullword ascii
        $s225 = "CryptGenKey" fullword ascii
        $s226 = "__getmainargs" fullword ascii
        $s227 = "`1^9tdb" fullword ascii
        $s228 = "mK~}k=P" fullword ascii
        $s229 = "ADVAPI32.dll" fullword ascii
        $s230 = "GetComputerNameW" fullword ascii
        $s231 = "!This program cannot be run in DOS mode." fullword ascii
        $s232 = "WANACRY!" fullword ascii
        $s233 = "incorrect header check" fullword ascii
        $s234 = "_mbsstr" fullword ascii
        $s235 = "Le\"zE^f1" fullword ascii
        $s236 = "msg/m_german.wnry" fullword ascii
        $s237 = "\"Df\"*T~*" fullword ascii
        $s238 = "SHELL32.dll" fullword ascii
        $s239 = "8,4$6'9-$:.6*1#?pXhH~SeAlNrZbE" fullword ascii
        $s240 = "LockResource" fullword ascii
        $s241 = "#cMe&(;[Ip" fullword ascii
        $s242 = "advapi32.dll" fullword ascii
        $s243 = "Lj&&lZ66~A??" fullword ascii
        $s244 = "L3koq_ >" fullword ascii
        $s245 = "??1type_info@@UAE@XZ" fullword ascii
        $s246 = "msg/m_danish.wnry" fullword ascii
        $s247 = "^Md]\"lN" fullword ascii
        $s248 = "EGBkV6\"rnL9" fullword ascii
        $s249 = "?-3t/''" fullword ascii
        $s250 = "GetStartupInfoA" fullword ascii
        $s251 = "tJ9@0O(" fullword ascii
        $s252 = "!A$U>=+" fullword ascii
        $s253 = "2dV2:tN:" fullword ascii
        $s254 = "tlHt Ht" fullword ascii
        $s255 = "9d|!]`[" fullword ascii
        $s256 = "GlobalFree" fullword ascii
        $s257 = "V22dN::t" fullword ascii
        $s258 = "nyMZ?%g;" fullword ascii
        $s259 = "QeFbF~TiKwZ" fullword ascii
        $s260 = "[d+?8d[" fullword ascii
        $s261 = "EnterCriticalSection" fullword ascii
        $s262 = "LoadResource" fullword ascii
        $s263 = "msg/m_finnish.wnry~" fullword ascii
        $s264 = "\"\"Df**T~" fullword ascii
        $s265 = "kEs##Q^!" fullword ascii
        $s266 = "r;#r7iS|1" fullword ascii
        $s267 = "s]R\",XC(" fullword ascii
        $s268 = "CreateFileA" fullword ascii
        $s269 = "??3@YAXPAX@Z" fullword ascii
        $s270 = "VirtualFree" fullword ascii
        $s271 = "CreateProcessA" fullword ascii
        $s272 = "invalid literal/length code" fullword ascii
        $s273 = "oversubscribed dynamic bit lengths tree" fullword ascii
        $s274 = "E65etRIv4" fullword ascii
        $s275 = "SetLastError" fullword ascii
        $s276 = "*4q4[`V" fullword ascii
        $s277 = "+[_JQ}" fullword ascii
        $s278 = "\"t=.|Vbq-" fullword ascii
        $s279 = "invalid stored block lengths" fullword ascii
        $s280 = ":95e`Il" fullword ascii
        $s281 = "$8,4-6'96$:.?*1#HpXhA~SeZlNrSbE" fullword ascii
        $s282 = "=1azT)8^y" fullword ascii
        $s283 = "__p__fmode" fullword ascii
        $s284 = "buffer error" fullword ascii
        $s285 = "^Ml,L;0" fullword ascii
        $s286 = "!#pHA[P" fullword ascii
        $s287 = "*@~CS%1" fullword ascii
        $s288 = "~|c<caKm2" fullword ascii
        $s289 = "C77nYmm" fullword ascii
        $s290 = "_adjust_fdiv" fullword ascii
        $s291 = "7#z y,:" fullword ascii
        $s292 = "e\".E~^G" fullword ascii
        $s293 = "pp|B>>q" fullword ascii
        $s294 = "SetFilePointer" fullword ascii
        $s295 = "RegCloseKey" fullword ascii
        $s296 = "strrchr" fullword ascii
        $s297 = "USER32.dll" fullword ascii
        $s298 = "too many length or distance symbols" fullword ascii
    condition: 
        any of them and
        uint32(uint32(0x3C)) == 0x4550
}