RE: SYN FIN Scan with src port == dst port

From: Fernando Cardoso (fernando.cardosoat_private)
Date: Wed Jun 20 2001 - 01:19:28 PDT

  • Next message: Andrew Heath: "New maniac rootkit"

    Hi Nicolas
    >
    > here some logs from probes done by compromised boxes.
    > The first one (hacked_1) is a default RedHat 6.2 and the second one
    > (hacked_2) is a default Cobalt 5.0
    > Admins have been notified.
    >
    > Jun 17 21:23:22 my_box_1 snort[468]: SCAN-SYN FIN: hacked_1:511 ->
    > my_box_1:511
    > Jun 17 21:23:22 my_box_2 snort[5207]: SCAN-SYN FIN: hacked_1:511 ->
    > my_box_2:511
    [...]
    .
    > Every packet have the same values for a few fields :
    > TOS:0x0 ID:39426 IpLen:20 DgmLen:40 Win: 0x404  TcpLen: 20
    >
    > Have you ever seen that ?
    
    Everytime :) This is for sure a synscan probe. It has all the symptoms:
    source port=destination port, ID=39426 and Window=404.
    
    If you were using the Whitehats signatures for Snort you would find a rule
    for that sort of scan.
    
    Cheers
    
    Fernando
    
    
    --
    Fernando Cardoso - Security Consultant       WhatEverNet Computing, S.A.
    Phone : +351 21 7994200                      Praca de Alvalade, 6 - Piso 6
    Fax   : +351 21 7994242                      1700-036 Lisboa - Portugal
    email : fernando.cardosoat_private     http://www.whatevernet.com/
    
    
    
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