From: kponds at the-pentagon.com (Kevin W Ponds)
Subject: The PACKET 0' DEATH FastTrack network vulnerability

God forbid the RIAA find out about this, they'll have a field day.

I'd worry more about them than script kiddies ( although they are pretty
close to the same thing ).
----------------------------------------------
Original Message
From: "random nut"<random_nut@...oo.com>
Subject: [Full-Disclosure] The PACKET 0' DEATH FastTrack network
vulnerability
Date: Sun, 25 May 2003 21:32:35 -0700 (PDT)

>
>The PACKET 0' DEATH FastTrack network vulnerability
>===================================================
>
>Vulnerability Overview
>----------------------
>There exists a vulnerability in the FastTrack network
>core that can be used by an attacker to take control
>of all FastTrack network supernodes. The attacker can
>either crash all supernodes or insert arbitrary code
>in each supernode's address space. Crashing all
>supernodes means that no-one can search for files on
>the FT network or connect to the FT network.
>
>A little FastTrack network background
>-------------------------------------
>The FastTrack (FT) network is the most popular p2p
>network in use today. At any given time 3-5 million
>people are connected to the FT network, and even more
>people have an FT client application, such as Kazaa,
>iMesh, or Grokster, installed on their computer.
>According to Sharman Networks (owner of Kazaa), Kazaa
>has been downloaded over 228 million times and each
>week 2.5 million people download Kazaa.
>
>The FT network is a decentralized network, and each
>client must connect to a supernode to be able to
>search for files. The most recent supernode list is
>stored in the registry. Up to 200 supernode IPs and
>ports can be stored. Not everyone can become a
>supernode. To become a supernode you must have a
>Windows NT/2000/XP OS, enough RAM, fast enough CPU, a
>non-local IP, fast Internet connection, and various
>other requirements imposed by the application itself.
>Each supernode typically has 100-300 clients connected
>at a given time, but it's possible to have up to 1000
>clients per supernode, but Kazaa internally limits
>this to 600. This and a lot more FT network options
>can be easily changed by whomever controls the FT
>network. Only they have the private RSA key needed to
>sign the FT network options packet (stored in the
>registry as network_config once authenticated). They
>also can use that packet to send update notifications
>to all clients. Last time this happened was when Kazaa
>v2.0.2 was released, which probably was sometimes in
>Oct/Nov 2002.
>
>To protect the FT network from people who wants to
>reverse engineer the protocol, the owners of the FT
>network added encryption to all supernode packets. The
>encryption seems to be made by the FT network
>creators. Nothing else is encrypted, such as files
>transferred to other users.
>
>Vulnerability Information
>-------------------------
>Packet 0 (possibly called "KAZAA_CONNECTION_INFO", but
>from here on called "Packet 0' death", note the zero)
>is used to send up to 200 supernode IPs to clients and
>supernodes. The supernodes' packet 0' death handler
>(possibly class "supernode_connection_t") is different
>from the other packet 0' death handlers, and it also
>contains the buffer overflow bug. The supernode packet
>0' death handler assumes only 200 supernode entries
>can be received, but if you send more you can
>overwrite the return address and more of the stack.
>
>The size of the packet must be a multiple of 8 bytes
>or the whole packet is ignored, and since max packet
>size is 65535 bytes, a total of 8191 supernode entries
>can be sent. Of these 8-byte entries, only the first 6
>bytes are stored on the stack. This means that you can
>send 49146 bytes of code to each supernode. If more is
>required the code could download the rest manually.
>Format of each entry:
>
>DWORD = Supernode IP in network order.
>WORD  = Supernode port in network order.
>BYTE  = Can't be used by attacker's code. Set it to 0.
>BYTE  = Can't be used by attacker's code. Set it to 0.
>
>The IP and port fields are later BSWAP'd by the FT
>code.
>
>The IP cannot be a private IP address. Kazaa v2.0.2
>considers these IP ranges to be private and ignores
>all packet entries with private IPs:
>
>* 127.b.c.d
>* 10.b.c.d
>* 0.b.c.d
>* 172.16.0.0 - 172.31.255.255
>* 192.168.c.d
>* 255.255.255.255
>
>Also, the supernode port cannot equal 0000h. Kazaa
>ignores all entries whose port equals 0.
>
>I tested executing code a couple of times, and it may
>only work about 50% of the time since the stack
>sometimes has another address. Instead of executing
>code the supernode will just crash.
>
>Since executing code doesn't work all the time, a
>possible exploit could first download all supernode
>IPs and ports from the supernode. Then send the packet
>0' death and try to execute code. If the infected
>supernode doesn't reply back within say 30 secs, we
>can assume it crashed. If it didn't crash, ignore all
>supernode IPs we downloaded and let the infected
>supernode use them. Now try next supernode. When no
>more left, call ExitProcess.
>
>With Kazaa v2.0.2, all that is required to crash the
>supernode is to send 203 entries. Example: Send packet
>0' death, 203 entries all equal to: 0FFFFFFFEh,
>0FFFFFFFFh.
>
>Discovery
>---------
>I discovered this vulnerability either in Dec 2002 or
>Jan 2003 when writing K++
>(http://www.geocities.com/random_nut/). Since there
>will soon be Open Source FT implementations using the
>FT network I notified Sharman Networks (owner of
>Kazaa) and Joltid (owner of FastTrack network). I
>waited 2 weeks but didn't get a reply.
>
>Affected programs
>-----------------
>Kazaa v2.0.2 has been tested. But it's very likely
>that this bug is present in previous and later Kazaa
>versions, such as the latest Kazaa v2.1.0 which was
>released a couple of months ago. It's also very
>possible that iMesh and Grokster also are affected.
>
>Testing
>-------
>I used a modified K++ to make two of my computers
>supernodes, and then sent a command to the other
>supernode to crash it. Kazaa v2.0.2 was tested. I
>don't have any intentions at the moment to release any
>exploit code since all script kiddies in the world
>would use it to close down the FT network or parts of
>it.
>
>Contact
>-------
>random_nut@...oo.com - I don't check it often, though,
>so be patient. ;)
>
>Misc
>----
>http://www.geocities.com/random_nut/ - K++
>http://www.kazaa.com/ - Owner of Kazaa
>http://www.joltid.com/ - Owner of FT network
>
>
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>_______________________________________________
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>

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