RE: TCP port 139 probes

From: Dan Irwin (danat_private)
Date: Tue Jul 09 2002 - 16:20:34 PDT

  • Next message: H C: "Re: Possible System Compromise"

    I noticed an increase in smb scanning last week, with a lot of machines
    on asian or US cable/dsl networks probing networks here.
    
    At least one of these machines appeared to be insecure and i could
    enumerate shares etc with smbclient -L.
    
    According to my logs, before July 1 2002, we had 4 netbios probes (This
    machine was only installed in mid June).
    
    On July 1 we recieved around 70 probes, and approx. 68 on July 4. 75
    probes sofar today. Other days vary a lot.
    
    Infected machines appear to be scanning large ip address ranges. These
    machines are scanning every address on our /28 net. (Logs below)
    
    Perhaps a new worm targetting insecure windows machines?
    
    Dan.
    
    <snip>
    Jul 10 09:12:37 xxxxx kernel: fwreject IN=ppp0 OUT=eth0
    SRC=67.225.115.84 DST=x.x.x.119 LEN=48 TOS=0x00 PREC=0x00 TTL=106
    ID=38950 DF PROTO=TCP SPT=21595 DPT=139 WINDOW=8192 RES=0x00 SYN URGP=0 
    Jul 10 09:12:37 xxxxx kernel: fwreject IN=ppp0 OUT= MAC=
    SRC=67.225.115.84 DST=x.x.x.127 LEN=48 TOS=0x00 PREC=0x00 TTL=106
    ID=39206 DF PROTO=TCP SPT=21569 DPT=139 WINDOW=8192 RES=0x00 SYN URGP=0 
    Jul 10 09:12:39 xxxxx kernel: fwreject IN=ppp0 OUT=eth0
    SRC=67.225.115.84 DST=x.x.x.120 LEN=48 TOS=0x00 PREC=0x00 TTL=104
    ID=39974 DF PROTO=TCP SPT=21317 DPT=139 WINDOW=8192 RES=0x00 SYN URGP=0 
    Jul 10 09:12:40 xxxxx kernel: fwreject IN=ppp0 OUT=eth0
    SRC=67.225.115.84 DST=x.x.x.121 LEN=48 TOS=0x00 PREC=0x00 TTL=106
    ID=40998 DF PROTO=TCP SPT=21539 DPT=139 WINDOW=8192 RES=0x00 SYN URGP=0 
    Jul 10 09:12:42 xxxxx kernel: fwreject IN=ppp0 OUT=eth0
    SRC=67.225.115.84 DST=x.x.x.122 LEN=48 TOS=0x00 PREC=0x00 TTL=106
    ID=42022 DF PROTO=TCP SPT=21554 DPT=139 WINDOW=8192 RES=0x00 SYN URGP=0 
    Jul 10 09:12:43 xxxxx kernel: fwreject IN=ppp0 OUT=eth0
    SRC=67.225.115.84 DST=x.x.x.123 LEN=48 TOS=0x00 PREC=0x00 TTL=106
    ID=43046 DF PROTO=TCP SPT=21561 DPT=139 WINDOW=8192 RES=0x00 SYN URGP=0 
    Jul 10 09:12:45 xxxxx kernel: fwreject IN=ppp0 OUT=eth0
    SRC=67.225.115.84 DST=x.x.x.124 LEN=48 TOS=0x00 PREC=0x00 TTL=105
    ID=44070 DF PROTO=TCP SPT=21596 DPT=139 WINDOW=8192 RES=0x00 SYN URGP=0 
    Jul 10 09:12:46 xxxxx kernel: fwreject IN=ppp0 OUT=eth0
    SRC=67.225.115.84 DST=x.x.x.125 LEN=48 TOS=0x00 PREC=0x00 TTL=106
    ID=45094 DF PROTO=TCP SPT=21599 DPT=139 WINDOW=8192 RES=0x00 SYN URGP=0 
    Jul 10 09:12:48 xxxxx kernel: fwreject IN=ppp0 OUT= MAC=
    SRC=67.225.115.84 DST=x.x.x.126 LEN=48 TOS=0x00 PREC=0x00 TTL=107
    ID=46118 DF PROTO=TCP SPT=21488 DPT=139 WINDOW=8192 RES=0x00 SYN URGP=0 
    Jul 10 09:12:49 xxxxx kernel: fwreject IN=ppp0 OUT= MAC=
    SRC=67.225.115.84 DST=x.x.x.127 LEN=48 TOS=0x00 PREC=0x00 TTL=106
    ID=47142 DF PROTO=TCP SPT=21569 DPT=139 WINDOW=8192 RES=0x00 SYN URGP=0
    <snip>
    
    --
    Dan Irwin - Systems Administrator
    Jackie's Wholesale Nurseries Pty Ltd
    Email: danat_private
    Phone: 07 3888 2481
    Fax: 07 3888 2530
    Postal: 10 Gleeson Road Burpengary Queensland 4505
    Email: infoat_private
    Web: http://www.jackies.com.au
    
    
    -----Original Message-----
    From: Pavel Kankovsky [mailto:peakat_private]
    Sent: Wednesday, 10 July 2002 6:22 AM
    To: incidentsat_private
    Subject: TCP port 139 probes
    
    
    I have detected a noticeable increase of (blocked) attempts to connect
    to the TCP port 139 on machines in our network. Look at these numbers
    (number of blocked packets per a day):
    
          1	Jun 10
          5	Jun 11
         13	Jun 12
         15	Jun 13
          3	Jun 15
          3	Jun 16
          4	Jun 17
         13	Jun 18
         18	Jun 19
         16	Jun 20
         15	Jun 21
          4	Jun 22
          2	Jun 23
         23	Jun 24
         18	Jun 25
         44	Jun 26
         95	Jun 27
        112	Jun 28
         84	Jun 29
         53	Jun 30
        130	Jul  1
        191	Jul  2
        227	Jul  3
        235	Jul  4
        226	Jul  5
        185	Jul  6
        167	Jul  7
        350	Jul  8
        199	Jul  9
    
    These probes are not (ordinary) scans but isolated attempts by seemingly
    random remote IP addresses to open connection to seemingly random local
    IP
    addresses. In many cases, the destination is an unused address.
    
    This is very suspicious.
    
    --Pavel Kankovsky aka Peak  [ Boycott
    Microsoft--http://www.vcnet.com/bms ]
    "Resistance is futile. Open your source code and prepare for
    assimilation."
    
    
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