Access Level 1
# curl http://ctf.noconname.org/4cbe48a830c4cd2d4ac9e6e9373e3055/index.html
# curl --silent http://ctf.noconname.org/4cbe48a830c4cd2d4ac9e6e9373e3055/crypto.js | sed 's/eval/console.log/'
# node
> var _0x52ae=["\x66\x20\x6F\x28\x38\x29\x7B\x63\x20\x69\x2C\x6A\x3D\x30\x3B\x6B\x28\x69\x3D\x30\x3B\x69\x3C\x38\x2E\x6C\x3B\x69\x2B\x2B\x29\x7B\x6A\x2B\x3D\x28\x38\x5B\x69\x5D\x2E\x73\x28\x29\x2A\x28\x69\x2B\x31\x29\x29\x7D\x67\x20\x74\x2E\x75\x28\x6A\x29\x25\x76\x7D\x66\x20\x70\x28\x68\x29\x7B\x68\x3D\x68\x2E\x71\x28\x30\x29\x3B\x63\x20\x69\x3B\x6B\x28\x69\x3D\x30\x3B\x69\x3C\x77\x3B\x2B\x2B\x69\x29\x7B\x63\x20\x35\x3D\x69\x2E\x78\x28\x79\x29\x3B\x6D\x28\x35\x2E\x6C\x3D\x3D\x31\x29\x35\x3D\x22\x30\x22\x2B\x35\x3B\x35\x3D\x22\x25\x22\x2B\x35\x3B\x35\x3D\x7A\x28\x35\x29\x3B\x6D\x28\x35\x3D\x3D\x68\x29\x41\x7D\x67\x20\x69\x7D\x66\x20\x6E\x28\x38\x29\x7B\x63\x20\x69\x2C\x61\x3D\x30\x2C\x62\x3B\x6B\x28\x69\x3D\x30\x3B\x69\x3C\x38\x2E\x6C\x3B\x2B\x2B\x69\x29\x7B\x62\x3D\x70\x28\x38\x2E\x71\x28\x69\x29\x29\x3B\x61\x2B\x3D\x62\x2A\x28\x69\x2B\x31\x29\x7D\x67\x20\x61\x7D\x66\x20\x42\x28\x39\x29\x7B\x63\x20\x32\x3B\x32\x3D\x6E\x28\x39\x2E\x64\x2E\x65\x29\x3B\x32\x3D\x32\x2A\x28\x33\x2B\x31\x2B\x33\x2B\x33\x2B\x37\x29\x3B\x32\x3D\x32\x3E\x3E\x3E\x36\x3B\x32\x3D\x32\x2F\x34\x3B\x32\x3D\x32\x5E\x43\x3B\x6D\x28\x32\x21\x3D\x30\x29\x7B\x72\x28\x27\x44\x20\x64\x21\x27\x29\x7D\x45\x7B\x72\x28\x27\x46\x20\x64\x20\x3A\x29\x27\x29\x7D\x39\x2E\x47\x2E\x65\x3D\x6E\x28\x39\x2E\x64\x2E\x65\x29\x3B\x39\x2E\x48\x2E\x65\x3D\x22\x49\x22\x2B\x6F\x28\x39\x2E\x64\x2E\x65\x29\x3B\x67\x20\x4A\x7D","\x7C","\x73\x70\x6C\x69\x74","\x7C\x7C\x72\x65\x73\x7C\x7C\x7C\x68\x65\x78\x5F\x69\x7C\x7C\x7C\x73\x74\x72\x7C\x66\x6F\x72\x6D\x7C\x7C\x7C\x76\x61\x72\x7C\x70\x61\x73\x73\x77\x6F\x72\x64\x7C\x76\x61\x6C\x75\x65\x7C\x66\x75\x6E\x63\x74\x69\x6F\x6E\x7C\x72\x65\x74\x75\x72\x6E\x7C\x66\x6F\x6F\x7C\x7C\x68\x61\x73\x68\x7C\x66\x6F\x72\x7C\x6C\x65\x6E\x67\x74\x68\x7C\x69\x66\x7C\x6E\x75\x6D\x65\x72\x69\x63\x61\x6C\x5F\x76\x61\x6C\x75\x65\x7C\x73\x69\x6D\x70\x6C\x65\x48\x61\x73\x68\x7C\x61\x73\x63\x69\x69\x5F\x6F\x6E\x65\x7C\x63\x68\x61\x72\x41\x74\x7C\x61\x6C\x65\x72\x74\x7C\x63\x68\x61\x72\x43\x6F\x64\x65\x41\x74\x7C\x4D\x61\x74\x68\x7C\x61\x62\x73\x7C\x33\x31\x33\x33\x37\x7C\x32\x35\x36\x7C\x74\x6F\x53\x74\x72\x69\x6E\x67\x7C\x31\x36\x7C\x75\x6E\x65\x73\x63\x61\x70\x65\x7C\x62\x72\x65\x61\x6B\x7C\x65\x6E\x63\x72\x79\x70\x74\x7C\x34\x31\x35\x33\x7C\x49\x6E\x76\x61\x6C\x69\x64\x7C\x65\x6C\x73\x65\x7C\x43\x6F\x72\x72\x65\x63\x74\x7C\x6B\x65\x79\x7C\x76\x65\x72\x69\x66\x69\x63\x61\x74\x69\x6F\x6E\x7C\x79\x65\x73\x7C\x74\x72\x75\x65","","\x66\x72\x6F\x6D\x43\x68\x61\x72\x43\x6F\x64\x65","\x72\x65\x70\x6C\x61\x63\x65","\x5C\x77\x2B","\x5C\x62","\x67"];console.log(function (_0x7038x1,_0x7038x2,_0x7038x3,_0x7038x4,_0x7038x5,_0x7038x6){_0x7038x5=function (_0x7038x3){return (_0x7038x3<_0x7038x2?_0x52ae[4]:_0x7038x5(parseInt(_0x7038x3/_0x7038x2)))+((_0x7038x3=_0x7038x3%_0x7038x2)>35?String[_0x52ae[5]](_0x7038x3+29):_0x7038x3.toString(36));} ;if(!_0x52ae[4][_0x52ae[6]](/^/,String)){while(_0x7038x3--){_0x7038x6[_0x7038x5(_0x7038x3)]=_0x7038x4[_0x7038x3]||_0x7038x5(_0x7038x3);} ;_0x7038x4=[function (_0x7038x5){return _0x7038x6[_0x7038x5];} ];_0x7038x5=function (){return _0x52ae[7];} ;_0x7038x3=1;} ;while(_0x7038x3--){if(_0x7038x4[_0x7038x3]){_0x7038x1=_0x7038x1[_0x52ae[6]]( new RegExp(_0x52ae[8]+_0x7038x5(_0x7038x3)+_0x52ae[8],_0x52ae[9]),_0x7038x4[_0x7038x3]);} ;} ;return _0x7038x1;} (_0x52ae[0],46,46,_0x52ae[3][_0x52ae[2]](_0x52ae[1]),0,{}));
> function simpleHash(str){
... var i,hash=0;
... for(i=0;i<str.length;i++){
..... hash+=(str[i].charCodeAt()*(i+1))
..... }
... return Math.abs(hash)%31337
... }
> function ascii_one(foo) {
... foo = foo.charAt(0);
... var i;
... for (i = 0; i < 256; ++i) {
..... var hex_i = i.toString(16);
..... if (hex_i.length == 1) hex_i = "0" + hex_i;
..... hex_i = "%" + hex_i;
..... hex_i = unescape(hex_i);
..... if (hex_i == foo) break
..... }
... return i
... }
> function numerical_value(str) {
... var i, a = 0, b;
... for (i = 0; i < str.length; ++i) {
..... b = ascii_one(str.charAt(i));
..... a += b * (i + 1)
..... }
... return a
... }
> function encrypt(form) {
... var res;
... res = numerical_value(form.password.value);
... res = res * (3 + 1 + 3 + 3 + 7);
... res = res >>> 6;
... res = res / 4;
... res = res ^ 4153;
... if (res != 0) {
..... alert('Invalid password!')
..... } else {
..... alert('Correct password :)')
... }
... form.key.value = numerical_value(form.password.value);
... form.verification.value = "yes" + simpleHash(form.password.value);
... return true
... }
> var max=700000; var total=0; for (var i = 0; i < max; ++i) { total=(((i*17)>>>6)/4)^4153; if(total==0){console.log(i);}; };
> function init(dec,len){
... var deckey=new Array();
... for(var i=1; i<=len; i++){ deckey[i]=dec; }
... return deckey;
... }
> function add(deckey,len){
... var counter=0;
... for(var i=1; i<=len; i++){ counter+=deckey[i]*i; }
... return counter;
... }
> var len, dist, deckey, count, key;
> len=100;
> for(var dec=32; dec<=126; dec++){
... dist=126-dec;
... for(var i=1; i<=len; i++){
..... deckey=init(dec,i);
..... count=add(deckey,i);
..... diff=62540-count;
..... if((0<=diff)&&(diff<=dist)){
....... key=String.fromCharCode(dec+diff);
....... char=String.fromCharCode(dec);
....... for(var j=1; j<=i-1; j++){
......... key+=char;
......... }
....... console.log("key = '"+key+"'");
....... }
..... }
... }
> simpleHash('r1111111111111111111111111111111111111111111111111');
# curl --silent --request POST --data 'password=r1111111111111111111111111111111111111111111111111&key=62540&verification=yes31203' http://ctf.noconname.org/4cbe48a830c4cd2d4ac9e6e9373e3055/login.php
# cat level_1.c
# gcc -o level_1 level_1.c
# ./level_1 62540 50
> simpleHash(' ! <~~~~~~~~~~~~~~~~~~~~~~~');
# curl --silent --request POST --data 'password= ! <~~~~~~~~~~~~~~~~~~~~~~~&key=62554&verification=yes31217' http://ctf.noconname.org/4cbe48a830c4cd2d4ac9e6e9373e3055/login.php
Access Level 2
# curl --silent --output level.apk http://ctf.noconname.org/ad4d4084729af5c8faef2df8636c450e/level.apk
# unzip level.apk
# dex2jar classes.dex
# jd-gui classes_dex2jar.jar # and code review
# cd res/raw
# mv i.png qr-f.png
# mv j.png qr-e.png
# mv d.png qr-d.png
# mv h.png qr-c.png
# mv e.png qr-3.png
# mv l.png qr-2.png
# mv o.png qr-7.png
# mv n.png qr-b.png
# mv p.png qr-8.png
# mv m.png qr-1.png
# mv f.png qr-0.png
# mv c.png qr-4.png
# mv k.png qr-5.png
# mv g.png qr-6.png
# mv a.png qr-9.png
# mv b.png qr-a.png
# montage *.png -tile 4x4 -geometry +0+0 qr.png
# zbarimg --raw --quiet qr.png
Access Level 3
# curl --silent --output level.elf http://ctf.noconname.org/94999ecd63b3764ac334bcab4c4960d5/level.elf
# file level.elf
# chmod +x level.elf
# gdb -q level.elf
(gdb) set disassembly-flavor intel
(gdb) x/s 0x4024a8
(gdb) x/25i 0x00000000004010f3
(gdb) x/30s 0x6033a0
# echo ' SURPRISE!' | ./level.elf
# gdb -q level.elf
(gdb) set disassembly-flavor intel
(gdb) break main
(gdb) run
(gdb) x/2i 0x40117b
(gdb) set $rip = 0x40117b
(gdb) continue
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