[Pkg-utopia-maintainers] Bug#767625: avahi-daemon leaks MAC address
Blue Beret
debian_bts at ramus.wz.cz
Sat Nov 1 14:21:19 UTC 2014
Package: avahi-daemon
Version: 0.6.31-4
Severity: important
Tags: ipv6
Dear Maintainer,
I noticed that when I use NetworkManager to connect to a wired Ethernet network using a custom (or "cloned") MAC address, avahi-daemon has access to both MAC addresses and uses them inconsistently in MDNS queries, leaking them both.
To reproduce, create a wired connection in NetworkManager with a cloned MAC, then run a network sniffer such as Wireshark, connect to the network, and observe MDNS communication. You will see a MDNS query to ff02::fb containing a question in the format "hostname [MAC address]._workstation._tcp.local", where "hostname" is replaced by your machine's hostname and "MAC address" is the original (not cloned) MAC address of your Ethernet adapter.
Ideally, I would expect avahi-daemon to use the "cloned" MAC address, not the original one, in the query. The current behaviour causes an information leak where an eavesdropper can make a connection between your original MAC address and your "cloned" MAC address.
-- System Information:
Debian Release: jessie/sid
APT prefers unstable
APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)
Kernel: Linux 3.16-3-amd64 (SMP w/4 CPU cores)
Locale: LANG=cs_CZ.utf8, LC_CTYPE=cs_CZ.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Versions of packages avahi-daemon depends on:
ii adduser 3.113+nmu3
ii bind9-host [host] 1:9.9.5.dfsg-5
ii dbus 1.8.8-2
ii host 1:9.9.5.dfsg-5
ii init-system-helpers 1.21
ii libavahi-common3 0.6.31-4
ii libavahi-core7 0.6.31-4
ii libc6 2.19-12
ii libcap2 1:2.24-6
ii libdaemon0 0.14-6
ii libdbus-1-3 1.8.8-2
ii libexpat1 2.1.0-6
ii lsb-base 4.1+Debian13+nmu1
Versions of packages avahi-daemon recommends:
ii libnss-mdns 0.10-6
Versions of packages avahi-daemon suggests:
ii avahi-autoipd 0.6.31-4
-- no debconf information
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