DoS attack for ircd's by oversized PTR record

From: Goblin (goblinat_private)
Date: Fri Oct 29 1999 - 04:56:09 PDT

  • Next message: Nobuo Miwa: "Re: Netscape Messaging Server RCPT TO vul."

    (Read, 1st - Some domains and IP's listed here where substituted by fake
    ones, by their owners desire, but the examples are 100% true, and realy
    tested)
    
    I found this "bug" while trying to make a BIG sub-domain on my name server,
    what i just did was on my named.conf put:
    
    A.fccn.deve.estar.enganada.este.e.que.deve.ser.o.maior.nome.de.uma.maquina.e
    m.portugal    IN    A    111.111.111.111
    111.111.111.111.in-addr     IN    PTR
    A.fccn.deve.estar.enganada.este.e.que.deve.ser.o.maior.nome.de.uma.maquina.e
    m.portugal.xxxxxxx.pt.
    
    Changed the serial and did named.restart checked for it (if it's working or
    not).
    
    nslookup
    Default Server:  ptm-1.xxxxxxx.pt
    Address:  111.111.111.2
    
    > 111.111.111.111
    Server:  ptm-1.xxxxxxx.pt
    Address:  111.111.111.2
    
    Name:
    A.fccn.deve.estar.enganada.este.e.que.deve.ser.o.maior.nome.de.uma.maquina.e
    m.portugal.xxxxxxxx.pt
    Address:  111.111.111.111
    
    Well it was working, i now had a ip <-> name (resolving ip)
    So i decides to go to a Portuguese irc network (irc.ptlink.net), to my amaze
    the server crashed (only the ircd) when trying to resolve my ip, i tried
    another server and got the same result.
    I did some more checking and found it to be vurnerable, it was running
    Elite.PTlink3.3.1 a modified version of Elite ircd's.
    I probed arround for another ircd software and i found another network
    runnig u.2.9.32 (a undernet ircd) tried it and found it to be also
    vurlnerable.
    Continuing i tried it on Ptnet version PTnet1.5.39F witch is based on
    Dalnet's ircd's and found it to NOT be vurnerable , when i connected it
    tried to resolve my ip and failed, but it didnt crash, it continued the
    connection normaly.
    
    So let me put this on a small list of affected IRCd's.
    
    Vurnerable:
            Elite ircd (versions unknown)
            Ptlink ircd (all versions)
            Undernet ircd (u.2.9.32)
    Not vulnerable:
            Ptnet (versions unknow and 1.5.39F)
    
    (Note that this DoS could be applied for many other things)
    
    Any questions about this DoS in ircd's please mail me if a valid request i
    would be glad to help.
    
    
    Pedro Reis ( Goblin ) @ Portugal (irc.ptlink.net)
    



    This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 15:09:13 PDT