[tor-bugs] #9924 [Firefox Patch Issues]: Firefox queries the A record of the hostname of the machine it is running on.

[Tor Bug Tracker & Wiki]

#9924: Firefox queries the A record of the hostname of the machine it is running
on.
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 Reporter:  cypherpunks           |          Owner:  mikeperry
     Type:  defect                |         Status:  new
 Priority:  normal                |      Milestone:
Component:  Firefox Patch Issues  |        Version:
 Keywords:                        |  Actual Points:
Parent ID:                        |         Points:
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 When Firefox starts, it does a DNS query for the A record of the hostname
 of the machine it is running on.

 If that hostname resolves to a public IP address, then Firefox will have
 information that could be used to deanonymize the user, and it is unclear
 what Firefox is doing with that information or why it needs to collect it.

 This query is not done via Tor, it uses the system resolver, even when
 using TBB. This was discovered by configuring BIND to log queries and
 running tail -f on the query log while starting TBB Firefox and regular
 Firefox, which each exhibit this behavior shortly after starting.

 Some quick google searching seems to indicate that I am not the only
 person who has noticed this. Many people seem to have trouble getting
 Firefox to start if their machine's hostname does not resolve. I found one
 bug in the Mozilla bug tracker (sorry, I can't find it back again to note
 the number), where someone was complaining of exactly this, but the
 response was a denial that the behavior was happening.

 This should be looked into and it should be confirmed that nothing
 nefarious or negligent is being done with the result of that DNS query.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9924>
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