[ NNSquad ] Re: Google Hijacked

[Mikus Grinbergs <mikus@bga.com>]

In the context of this discussion, let me mention an actual 
occurrence that a while ago had me completely confused:

Linux distributions typically use the HTTP protocol to download 
software upgrades.  A friend uses a wireless modem (ISP supplied) 
with his DSL line.  I added a Linux system for his family members. 
At the time of this install, Linux upgrades worked fine.  At a later 
date, Linux upgrade attempts on this system started experiencing 
__consistent__ checksum errors.  Result -- unable to upgrade.


Turned out the electric utility had had an outage, which *reset* the 
wireless modem.  And now, whenever the HTTP protocol was used, the 
modem was __inserting__ (hijacking??) a warning that the connection 
had failed, and that the user's browser needed to be restarted.

Unfortunately, at that time the logic in the wireless modem that 
(when it thought the user had seen the warning) would remove this 
"helpful" added text worked only with Microsoft's HTTP sequences. 
[I am **not** kidding !!]  Since it did not "recognize" the HTTP 
sequences the Linux system was using, this wireless modem kept on 
inserting the warning text every time the Linux system tried HTTP. 
This added text caused the checksum on the received data to fail.

[I ended up contacting 2-WIRE (the manufacturer of the wireless 
modem).  They guided me through upgrading the wireless modem to the 
latest firmware version.  With it installed, a modem reset would 
insert its warning text only one time, no matter what kind of HTTP 
sequence was being used.]


Bottom line:  third-party changing of the content of transported
              information can have unforeseen consequences.

mikus