Data URL Scheme Note

0x01 causes

When I was doing the CTF today, I found a bunch of data, probably like this.

Data:image/jpg;base64, Ivborw0kggoaaaansuheugaaaiuaaacfcayaaab12js8aaaaaxnsr0iars4c6qaaaarnqu1baacxjwv8yquaaaajcehzcwaadsmaaa7dacdvqgqaaarzsurbv hhe7zkbitxifgtv/396tx564g1uouickg19hwpcdcrmj9m7/7n45zfdxe5z3sj7prhbf9rxo3p4llvypctbem80dvtp+ 3pndp9yf7tneqvvmczu/2lf78zhu+5i9yxv4t3t2o0/7eud68ot2h3lcft0l/ae9zlto+23ppvx7/rwjhbfcsi+3aw9z33m1gj7len+9bs+ pindt5ywt3dp71mfotxafku6f/2ud09i9y0n7nnd2nvwz06ntt+s7l+/68mjc5o0oswpcyexnfjfcsi+jw1ukprfv+ vdcxottdklqxmnszxy33lcpivtbpkux7/rwwlzk7q5jalzj7gcwn9ywj4lbw6slf+/68mjc5o0oswpcyexnfjfcsi+jw1ukprfv+vdcxotwe7a /i72pstj2zfshnotppz6xr9omjvectl2d7h3wu7avmh3mjsk5dfv+ndc3cswk7a/ i73pctl2dbvh3cqpv37xhxpmjrgctp1d7h2wk7zv2d3mjkn59bs+nda3iewefdnimyljnelp7h6bmytl1+/ 6cmlcjjyt9k0jbaykdaansfttbpkux7/rwwlzk1ho2dentjms1jmexu63uulsfv2udyfmtwi5yd800mzkumd6grvf5izj+ fw7pjzj7v12b33lsdtvsfuw75lux7/rw5ps3m/31rectp0wu2/5lun+9bs+pmnu/xzvfctj22+x+5bvku5fv+vdk+zeb/fwt5y0/ra7b/ ku6f71+++ht0v+5l3+tk935vapyd+8y5/29c4cpix5m3f5077emconjh/zln/ar3d+/flbpi+cmdentjksywn79bp5uk+yfztmppe2u2i5yz9+ Ih/3vfapxtw00mzklcfs00/k477k/ Tgym0batinlhh36isxflt78tpi605bdpbf7lhvct54mvwoawj6m4z0kdaytu3ti9yw3ug89txrhnle8tcm7sepmw3b3xo5zbndfepr0jmliezqgd5lumbbs7o nds9zgvvu06r3txpxcsxprw07ypyr1pqtnkumdkumdk5luaxzdwb/ eyx3lcfuupm6utdklqtmlqxnskjqnrxvrwzusbzlhn5lumzi2pyr1pir1tkpsp/f1y314h/utj+xtkjpt0uaupm6upm5jseo0ft34+ Vognlqdfuosn7inhvutj+ybrtpmd0n39goa3ce+jzyb3fpd+ pyt9k0jbaa7pht6ny3uyj8syw3uqwf9ywn7ppe2013spb2arnewt4nlbvfusl7lhh3tsjvplunecjwv7mcftqqbjsr1pur03tqsbkx/ wrjqj7jpw9knrpi6u3i6b21jn6y/yvm1r9mnlelgi0mdktmdt7akg9ofskzao+ Ztlnsjkatoljzow1vsjelpwfbp8nrimyljnwnl7r6f7zn3stcb32fppunti22mjhwmlbv7fr7p3cxdbhyhpzuoty20mzlumbbs7lv4pnoxdlpxhzzwojq10mz kumfasrtv4fvmxdlnxndywunqlfhuthv2w42n+4bds7wl3vuusksj5ua7z7/velpv2d3lw9k95spllfhuthv2w42n+ 4bds7wl3vuusksj5ua7z7/velpv2d3lw9k97avp6gq334x3kwlz+tukb5j+ho2/hx3ebr4l71ps5vs3sd8w/qnbfwv7in18f96npm3pb5o+ Yfottv8w9hg7+s68t0mb098mfcp0jxz/w+x+fpethvutn2y/m7fwnvm1+frzioklddy3gta33ld9bt7ce+ Bx5uvpg6sxnhdfaljfcsp2u3kl75lfm68/d5je0sb9q2f9yw3b7+ytvgd+bb7+vcen7yspmzxszrql3bocsn9kns4t2ujrk6to1eib6s52z3lcfit5ok9oi0dnkjpti22mu9g9ywn7retppkethjvj6kyntjnuyvcsj+y3kqfzxnlieuosj+ Xtyvkudt9yg3tqpm2d5cf50mkjessj+5ryvovdt9zgnhppcyf5sb60wklecsi+jzbvyvctn7inrtrcsx6sly2wklgcse+ j5bvyfcsn7qmrnnesn+rlk5umbw4sywn7lozmhh3a0u7zn99hadmrnjej5yr9snzzwj5taffsm++wtoxim5vecsi+jbs5yz+ 2thv2zxdywnakzu1iowgfkt2cse9b2j375jtcvtz+tux0vrxf9sxnkjrtt+t6rvyx37ac3re22j65svjn+olc35u/9tuw0/vwftszn0nqtd+ r67vyx37bcnrf2mj75izjneknun+v/awyuyntpqtnqze2uyntglvsjtst9vvtkhnqpm2utdk10mzqpe1js7pxz6j+ qx1lto20mzi2p0bati20awxjn+5m1g+1o8ypktzt0ubusjupktanlengnynl6tujo2zp3dtszkp2c8l+0xppm32hpfwtixpbmzentjms3zyw/ 7rg2kzfywn95mje9sxni22mzdcn7d+tktbtd1hapzkyst1z00ibkdnncftpa6tn9b2uxh5/s9rcbek37jr2+5skzpskzo4kdaavtg6/ jw1utqqbdxq7fupsz0psz0esotnxj4ffkjy3w9kno43dpiwpmywpsynjnemrk8nvszublengnczun5lumzlu2zgkzvtvwr/e0faj7xdzw/ bmkbgc7pbne1x3uqntn9h+nzdsz5wsy8lu3zzbdac72vaj7xdzw/bmkbgc7pbne1x3uqntn9h+ nzdsz5wsy8lu3zzbcsvewpys1lmtwg7y3nlcpm1jn05klp/d8trgzcljntuj5ybtlsfs05z046te8j8st23enjluuznybtjecsi+buk3tkos/ 8py1ebmkumdo4nlhu0tj+ztlntjpmtyp/r/i8pwi //fjzyb3jvv8pd/il+wwg5wb77d3/8pflliucg9+q5//6f4zynlbvfmo1y9ph7kfttbfhq+zyspmyvtbr7d1cvjp2yxvewn4ftmkjpt0ubmo1y9ph7kfttbfhq+ zyspmyvtbr7d1cvjp2yxvewn4ftmkjpt0ubmo1y9ftrg9y0n7fpd+pattk9o71st13mv7wd3lsfsu8p6lpo2t07vwxpxcy/typctj+xtw/ qwk7zptu9be9dzl+1g9y0n7fpd+pattk9o71st1/p7enotwg5wb5lumrptn3d/6b6+ex04yw4syw3utzi6u6pte+4/ 3dc3rw8nze1iucg9svjnarr9wv2n+/rm9egeuuksn7g3sepmjbzpup90x9+8ppwwn0mb72pyfzcn1rf8nhwffxxwhxpmjmnzxq3r7+be+pafhu +jr876cmlcjg2+q2h93zxy3/lt8h301vkftpibpm13nay/mxprw34avo++ouvdcxot7ozgu7e+ 5yt9xynlhh36dlfvfstcjlu50e6tbzlhf1diowgfvspvux8xn8lubrr761to2n+vwe7yp+9w9e5hze2ymxvt3vqwe/z3jzyt9uk7xl1+ 1gd3lx8avt8klhu2t5yc6f+/68ot2h3ln4bvn4nlhu0tjyf61+/68cr23/kn4ftnyrlhe8vjif71uz48id23/gn4fpnybtjecnkif/3+++ htnub0fd4zieutvlfro1y9ph7k05y+z3smsbyf93z9h6uxx095mtp3ec8klrfw3q7vcpxy+clpc/o+75ne8hbe2/udzv9x+sv/op/881/ sqtvcdpbh+waaaabjru5erkjggg==

At first, do not know what things, the only one can understand is the last two = =, and base64, to determine these things base64 coding.

Baidu found this is the RFC2397 agreement.

0x02 Results

The data URL scheme defines a new URL data scheme. Because some applications need to embed some small media data types directly into a Web page, reduce the number of links to the requested resource. The browser decodes and renders the image after it receives the data.

　　format:data:[<mediatype>][;base64],<data>

MediaType is the type of data, divided into types and subtypes.

Base64 is the supported encoding mode

The data embedded after the comma.

format supported by Data URL scheme:

Data : Text  data:text/Plain, text data  data:text/html,html code  data:text/  HTML;BASE64,BASE64 encoded HTML code  data:text/css,css code  data:text/css;base64,base64 coded CSS Code  data:text/javascript,javascript code  data:text/javascript;base64, Base64 encoded JavaScript code  data:image/gif;base64,base64 encoded GIF image data  data:image/png; BASE64,BASE64 encoded PNG image data  data:image/JPEG;BASE64,BASE64 encoded JPEG image data  data:image/x-icon; BASE64,BASE64 encoded icon image data  

Data URL Scheme Note