Is M1 broadband injecting Javascript into my web pages?

Recently on all the web pages that I surf on my PC, I have been seeing blurred images instead of the normally clear ones. I almost went to have my eyes checked, but turns out that it was due to a mysterious chunk of Javascript has been injected at the bottom of every web page that I visit. It’s frustrating because not only the images are blurred, some of the web pages are even broken and inaccessible due to the injected Javascript.

Well, how blur is blur? The first image is the original clear image:

and the following image is the one dished out by M1 and what I saw on my browser:

[ Start of technical paragraph. Feel free to skip this paragraph if it makes you giddy ]
When I view the source of the HTMLs, I notice a chunk of Javascript being injected at the bottom of every web page that I visit. This injected Javascript is extremely intrusive because it replaces all the images on web pages with compressed version of the images (for techies who are interested, I’ve listed this Javascript in its entirety at the bottom of this post). I did a further check at the University of Washington Web Integrity Checker and confirmed that the web pages has indeed been modified in transit after leaving the server and while on the way to my computer.

The question is: who is sneakily injecting Javascript into my web pages to replace all the images with the compressed and blurred versions?

My first suspect is naturally my ISP, M1 Broadband. As a simple test, I disconnected my notebook from M1 and connected to Wireless@SG instead. The problem disappeared! The images shown on web pages are the clear ones! I then connected my notebook back to M1 broadband, and the images are blurred again.

So on two occasions within 22 and 23 April 2008, I called up M1 Broadband technical support to inquire if they are purposely compressing all the images at their gateway. On both occasions, the technical support guy’s answer is a firm “No”, regardless of how hard I tried to reason with them. Sensing that these guys might be unaware of this issue themselves, I thanked them and hung up. Just before writing this blog entry, I sent an email to M1 to relate my problem again. Hopefully I can receive a better written reply from there.

If you’re using M1 Broadband and have been facing the same problem too for the past week or so, do leave a comment here. Thanks!

For techies who are interested, here is the injected Javascript in its entirety:

<SCRIPT LANGUAGE=”JavaScript”>
var ir_t;
var ir_g;
var ir_y;
var ir_u;
var mp;
var ir_find=new Array(’.gif’,’.GIF’,’.jpg’,’.JPG’,’.jpeg’,’.JPEG’);

function ir_r()
{
if(!ir_g.dontfetch)
{
if(ir_g.src.search(”mhtml”) != -1)
{
mp = ir_g.src.search(”!”);
if(mp != -1)
{
ir_g.src=ir_g.src.substring(mp+1);
}
}

ir_g.src=ir_g.src+’nguncompressed’;
}

ir_g.dontfetch=true;
ir_g.updateSrc=true;
ir_g.title = ir_g.oldTitle;
ir_g.alt = ir_g.oldAlt;
window.status=”;

}

function ir_c(event)
{
if(! event)
event = window.event;

lTargetTag = (null != event.srcElement) ? event.srcElement : event.target;

if(lTargetTag)
{
if(lTargetTag.tagName==”IMG”)
{
ir_g=lTargetTag;
if(!ir_g.dontfetch && !ir_g.updateSrc && !ir_y)
{
if(!ir_g.changeAlt)
{
ir_g.oldTitle = ir_g.title;
ir_g.title = ”;
ir_g.oldAlt = ir_g.alt;
ir_g.alt = ”;
ir_g.changeAlt = true;
}
window.status = ”;
ir_t=setTimeout(”ir_r();”, 1000*2);
}
}
}
}

function ir_e()
{
clearTimeout(ir_t);
window.status=”;
}

function ir_d(event)
{
if(! event)
event = window.event;

if(!ir_u && event.keyCode == 38 )
{
ir_u=true;
ir_y=true;
for (i = 0 ; i < document.images.length ; i++)
{
if(!(document.images[i].updateSrc))
{
for (j = 0 ; j < ir_find.length ; j++)
{
if((document.images[i].src).search(ir_find[j]) != -1)
{
if((document.images[i].src).search(”mhtml”) != -1)
{
mp = (document.images[i].src).search(”!”);
if(mp != -1)
{
(document.images[i].src)=(document.images[i].src).substring(mp+1);
}
}
document.images[i].src=document.images[i].src+’nguncompressed’;
break;
}
}
}
}
}

}

for (i = 0 ; i < document.images.length ; i++)
{
ir_y=false;
var lOnMouseOver = document.images[i].onmouseover;
if (lOnMouseOver == null)
{
for (j = 0 ; j < ir_find.length ; j++)
{
if((document.images[i].src).search(ir_find[j]) != -1)
{
document.images[i].onmouseover=ir_c;
break;
}
}
}
};

for (i = 0 ; i < document.images.length ; i++)
{
var lOnMouseOut = document.images[i].onmouseout;
if (lOnMouseOut == null)
{
document.images[i].onmouseout=ir_e;
}
};

</SCRIPT>

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